# An Idea, And If, Some Assistance Required.



## johan (27/4/15)

*What*
I've been contemplating to make a small indicator circuit for quite some time.

*Reason*
Now the "need" originates mainly from my social behavior at certain times. I've experienced too many times on a day/night out, getting so involved with conversations and too much "cold drinks" (like Oros), that I vape a battery beyond its safe discharge level without consciously noticing it.

Under normal conditions I would immediately notice it, and when measured, the battery would've discharged to round about 3.8V (roughly after 3ml of e-juice on a standard Reo bottle).

*How*
Apologies for all the waffle above. Now, what I intend to do, is design a simple circuit to emit a green light, if the battery's voltage is above x-voltage (when I press the firing button) and emit a red light when the battery voltage is below y-voltage (when I press the firing button). This little circuit should not be bigger than: width: 15mm x hight: 30mm x thick: 3mm. It will be easy to stick it behind the Reo or Kui juice bottle and emit the relevant colors. The circuit will draw less than 10mA when the fire button is pressed and no current when the fire button is not pressed. Connection would be easy; 1 x thin black wire tugged underneath the negative battery spring and 1 x thin red wire connected to the centre pin or leaf spring (positive side).

*Why*
Why do I need your assistance? The design is not the issue, but to get the pcb's made and purchasing small quantity of components are a costly affair, if I only do one/two for myself. If there is enough interest in something like this, what would you prefer to be the minimum discharge voltage to trigger the red emitting light? 3.0V or 3.2V or 3.5V etc.

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## Rob Fisher (27/4/15)

I'm in! Tell me what you need @johan! This could be a chicken dinner for Reonauts all over the planet!

PS What are the chances of having a deluxe version that shines blue when firing. Will look so kewl in an SL when is hide in a cupboard and vape!

Reactions: Funny 1


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## Andre (27/4/15)

Yes, interested for sure. 3.7V

Reactions: Agree 1 | Thanks 1


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## johan (27/4/15)

Rob Fisher said:


> I'm in! Tell me what you need @johan! This could be a chicken dinner for Reonauts all over the planet!
> 
> PS What are the chances of having a deluxe version that shines blue when firing. Will look so kewl in an SL when is hide in a cupboard and vape!



It can be any color you like as long as its either: white, red, green, violet, or blue. What I need now is a poll of at which voltage the "danger" light must come on?


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## BhavZ (27/4/15)

@johan brilliant idea, I too say 3.7v

Reactions: Thanks 1


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## Rob Fisher (27/4/15)

johan said:


> It can be any color you like as long as its either: white, red, green, violet, or blue. What I need now is a poll of at which voltage the "danger" light must come on?



Sweet! 3,7V for me please.

Reactions: Thanks 1


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## Riaz (27/4/15)

I would also be interested in one of these

3.7 would work, although i change batteries at 3.8

Reactions: Agree 3


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## johan (27/4/15)

Riaz said:


> I would also be interested in one of these
> 
> 3.7 would work, although i change batteries at 3.8



Riaz I also change battery round 3.8V, measured without load (coil in circuit). This circuit's main purpose will be to indicate "low" discharged voltage while load (coil in circuit) is connected. Some brands of batteries and especially aging batteries, will much quicker reach that threshold (i.e 3.8V) when the firing button is pressed, although it might measure 3.85V when no load is connected. Hope it makes sense.


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## Riaz (27/4/15)

johan said:


> Riaz I also change battery round 3.8V, measured without load (coil in circuit). This circuit's main purpose will be to indicate "low" discharged voltage while load (coil in circuit) is connected. Some brands of batteries and especially aging batteries, will much quicker reach that threshold (i.e 3.8V) when the firing button is pressed, although it might measure 3.85V when no load is connected. Hope it makes sense.


Makes perfect sense @johan 

I have to take my batteries out to check the voltage, so with this contraption is will make things a whole lot easier.

Reactions: Like 1


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## thekeeperza (27/4/15)

Awesome idea @johan. 3.7V for me

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## zadiac (27/4/15)

Excellent idea Ohm Johan. I too think 3.7v is good, although, I have to say that I immediately notice when my battery is around 3.6v as my vape change considerably in temp and taste. That's how I know it's time for a battery change. Also, by then my bottle is almost empty and I then squonk the last of the juice up the tube and change the battery

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## devdev (27/4/15)

3.7v sounds great @johan. And I would take a couple of these things to help make up the MoQ

Reactions: Thanks 1 | Creative 1


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## Philip Dunkley (27/4/15)

@johan, as discussed, I'm do in on this. 3.7v is also perfect for me.
Nice again Johan!!

Reactions: Thanks 1


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## Alex (27/4/15)

I would be most interested for sure.

Reactions: Thanks 1


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## ET (27/4/15)

Quick question, why not just attach one of those inline voltmeters?

Reactions: Like 1


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## Andre (27/4/15)

johan said:


> Riaz I also change battery round 3.8V, measured without load (coil in circuit). This circuit's main purpose will be to indicate "low" discharged voltage while load (coil in circuit) is connected. Some brands of batteries and especially aging batteries, will much quicker reach that threshold (i.e 3.8V) when the firing button is pressed, although it might measure 3.85V when no load is connected. Hope it makes sense.


My question flows from this: I usually change my battery between 3.7 and 3.8V as measured outside the device on your doohickey. Will the 3.7V light on your indicator be the same as this outside measurement? In other words, I would like the red to go on at the 3.7V (more or less) as if measured not under load.


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## johan (27/4/15)

Andre said:


> My question flows from this: I usually change my battery between 3.7 and 3.8V as measured outside the device on your doohickey. Will the 3.7V light on your indicator be the same as this outside measurement? In other words, I would like the red to go on at the 3.7V (more or less) as if measured not under load.



Andre that is not possible as no 2 batteries are exactly the same.

To illustrate: If I measure the battery without pressing the fire button (no load) and it reads ie: 4.15V, now when I press the fire button, it will read a lower voltage while current is drawn from the battery (ie: 4.00V). The difference between a no-load voltage measurement and measurement with load (pressing the fire button) varies from battery to battery and different coil resistance will also influence that difference. The lower the coil resistance, the bigger the difference will be.

The main function of this idea is to prevent discharging the battery below a safe low discharged voltage value. The measurement of battery is also only active while pressing the fire button. - I hope it makes sense.


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## Renesh (27/4/15)

@johan I'm in, 3.7v pls..and i'll take two of them (one for my incoming reo...and a spare for the next reo i buy)....

Reactions: Thanks 1


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## johan (27/4/15)

Renesh said:


> @johan I'm in, 3.7v pls..and i'll take two of them (one for my incoming reo...and a spare for the next reo i buy)....



LOL, its not even been designed yet - only an idea at this stage.


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## Renesh (27/4/15)

johan said:


> LOL, its not even been designed yet - only an idea at this stage.


No issues with that on myside... just means i'm on the list early... lol.
Fantastic idea though... will send you a pm

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## Andre (27/4/15)

johan said:


> Andre that is not possible as no 2 batteries are exactly the same.
> 
> To illustrate: If I measure the battery without pressing the fire button (no load) and it reads ie: 4.15V, now when I press the fire button, it will read a lower voltage while current is drawn from the battery (ie: 4.00V). The difference between a no-load voltage measurement and measurement with load (pressing the fire button) varies from battery to battery and different coil resistance will also influence that difference. The lower the coil resistance, the bigger the difference will be.
> 
> The main function of this idea is to prevent discharging the battery below a safe low discharged voltage value. The measurement of battery is also only active while pressing the fire button. - I hope it makes sense.


Makes perfect sense, thanks. Fact is, the measurement under load will be less the the measurement with no load. I think most of us change batteries at around 3.7V - as measured with no load. If this is true, seems to me we should go for the red light at something lower than the proposed 3.7V above to get nearer to the real world situation. Maybe 3.5 or 3.6V?

Reactions: Agree 3


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## johan (27/4/15)

I agree @Andre, I will do some measurements at some stage with different batteries and different coil resistances and see what is a mean average to work from, but my guess at this moment in time is closer to 3.3V under load.

Maybe if there are some other members that would like to play along, they can post their measurements here as well when they feel/taste that a battery needs to be replaced, ie:

Battery Brand:
Coil resistance:
Battery voltage without firing:
Battery voltage while firing:

Reactions: Like 1


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## Waltervh (27/4/15)

@johan How about this, Just an idea?


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## VapeSnow (27/4/15)

Waltervh said:


> @johan How about this, Just an idea?


That's to big for a Reo. If there is a very small model then it can work.

Reactions: Creative 1


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## Waltervh (27/4/15)

Dimensions: 24mmx20mmx12mm


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## kimbo (27/4/15)

I like the idea 

With my next change i will take down the details for you


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## Waltervh (27/4/15)

VapeSnow said:


> That's to big for a Reo. If there is a very small model then it can work.


OK Cool


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## kimbo (27/4/15)

Just a small PCB with two surface mount LED's and some @johan magic

Reactions: Agree 1


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## kimbo (27/4/15)

kimbo said:


> Just a small PCB with two surface mount LED's and some @johan magic


Even one surface mount RGB LED


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## johan (27/4/15)

Waltervh said:


> @johan How about this, Just an idea?



Way to big and I build something similar with much higher accuracy last year. Our goal is a circuit of the following maximum dimensions:

Width: 15mm x Height: 30mm x Thickness: 3mm

The purpose is to indicate: (a) battery OK and (b) replace battery

Reactions: Agree 1


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## Waltervh (27/4/15)

40mm x 20mm x 4.7mm

OK Cool, Just thought I'l Share .

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## johan (27/4/15)

Waltervh said:


> 40mm x 20mm x 4.7mm
> 
> OK Cool, Just thought I'l Share .



Very nice and it should fit within a Reo behind the juice bottle.


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## johan (27/4/15)

ET said:


> Quick question, why not just attach one of those inline voltmeters?



Yes you can do outside between 510 connector and RDA, but I just need something simple that lights up RED to alert me when my battery needs to be replaced.


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## johan (27/4/15)

devdev said:


> 3.7v sounds great @johan. And I would take a couple of these things to help make up the MoQ



Thanks, no MOQ, but quantities are required to get the costing as low as possible.

Reactions: Like 2


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## Andre (27/4/15)

johan said:


> Way to big and I build something similar with much higher accuracy last year. Our goal is a circuit of the following maximum dimensions:
> 
> Width: 15mm x Height: 30mm x Thickness: 3mm
> 
> The purpose is to indicate: (a) battery OK and (b) replace battery


I can do with only (b) if that would make a difference.

Reactions: Agree 1


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## ShaneW (27/4/15)

I'd be in for 2 please @johan, will take some measurements tomorrow. If I remember correctly 3.1-3.2V under load was the point at which the sx350 indicates low batt

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## Waltervh (27/4/15)

kimbo said:


> Even one surface mount RGB LED



A very good Idea, one led that shows green and at V? red.


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## johan (27/4/15)

Andre said:


> I can do with only (b) if that would make a difference.



its only 3 extra components and I will include a "hack" description, how to disable (a), if required.

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## ShaneW (27/4/15)

johan said:


> its only 3 extra components and I will include a "hack" description, how to disable (a), if required.



'Hack' the other LED off with side cutters

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## johan (27/4/15)

ShaneW said:


> I'd be in for 2 please @johan, will take some measurements tomorrow. If I remember correctly 3.1-3.2V under load was the point at which the sx350 indicates low batt



Yip my rough "in-the-small-head" calculation also guessed around the lower 3 point something volts.


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## johan (27/4/15)

ShaneW said:


> 'Hack' the other LED off with side cutters



one way or just cut 1 thin track with a utility knife .


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## Jakey (27/4/15)

Wow brilliant idea @johan. Im in for sure

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## WestCoastFog (27/4/15)

Hi John, it is a great idea for a mechanical mod, I was just wondering if a micro buzzer will not work better in this case because the device will be in your face when you trigger it and will be noticeable even in bright sun. I do understand that a buzzer is more expensive than a led but just my 2cents.Great idea

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## WestCoastFog (27/4/15)

And sorry last thought, a pot adjustable between 3,2 and 3.8 so every vaper can set it to his or her preference


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## johan (27/4/15)

WestCoastFog said:


> Hi John, it is a great idea for a mechanical mod, I was just wondering if a micro buzzer will not work better in this case because the device will be in your face when you trigger it and will be noticeable even in bright sun. I do understand that a buzzer is more expensive than a led but just my 2cents.Great idea





WestCoastFog said:


> And sorry last thought, a pot adjustable between 3,2 and 3.8 so every vaper can set it to his or her preference



Thanks for your comments, I do appreciate.

*Micro Buzzer*: Excellent idea, but I don't want to sit in church and stealth vape an me buzzer goes off  - I've got a couple of micro buzzers, and they are ear piercing loud.

*Pot*: I've learned over the years to NOT provide the end-user with an adjustable pot (especially surface mount pots), they WILL break it.

For those that are interested I will make it an Open Source design and they can modify to hearts content with pots etc.

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## BumbleBee (27/4/15)

Fantastic idea @johan, so simple but will be really handy. What's the chance that this doohickey can be made with clear plastic in a disc shape, 22mm in diameter with the LEDs mounted inside to light up the edge? Would be really cool for mech tube mods. I'd be in for a few of those for sure!

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## hands (27/4/15)

when juiced up on that much "Oros" you would need something to light up the room before you would pay any attention to it.
warning light at 3.7 would be great.

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## johan (27/4/15)

BumbleBee said:


> Fantastic idea @johan, so simple but will be really handy. What's the chance that this doohickey can be made with clear plastic in a disc shape, 22mm in diameter with the LEDs mounted inside to light up the edge? Would be really cool for mech tube mods. I'd be in for a few of those for sure!



Thanks. The problem with any "new" design is the manufacturing costs and you really need quantities to make it affordable to the end user. Just a rough example to put it in perspective: A simple gadget (nothing fancy), mass produced, that ends up in the market for a retail price of say R75. The company that designed that gadget and paid the once off manufacturing costs of pcb (printed circuit boards), pick and place setup etc, would spend in excess of minimum R2000 just for a few proto types, and that exclude any design time, testing, labour etc.

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## Xhale (27/4/15)

I dont quite know how the numbers would stack up. I firmly believe its a fantastic idea, but I cant decide where the lower limit should be.
Unloaded, I would say 3.6v is a battery I would consider putting back on charge.
loaded? as mentioned above, it really does depend on the load. A 0.5ohm coil at 16w or so is 2.8volts. I tended to vape around there on a sig100. So if that is the lower range, and members here want 3.4v or 3.7v then it'll be tough to design something static to cater for all users. Perhaps a small variable resistor would do the job...vape till you arent happy anymore, then set the pot such that the light changes and that is your setting. Pot range for light to go from red to green would be somewhere from 2.8v to 3.6v. Dirty contacts arent an issue, but different cells will drop a different amount when fired, so...ja...a variable resistor pls so we can set our own. You get those small surface mount ones that you need an itty-bitty screwdriver to adjust.

edit: oh the shame..I didnt read page 2...so if what I say has been discussed pls pardon me...I didnt notice the pagination

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## WestCoastFog (27/4/15)

johan said:


> Thanks for your comments, I do appreciate.
> 
> *Micro Buzzer*: Excellent idea, but I don't want to sit in church and stealth vape an me buzzer goes off  - I've got a couple of micro buzzers, and they are ear piercing loud.
> 
> ...



LOL, you vape in church? , no obviously not a high dB buzzer a more application appropriate one with a low dB. And it can be set to buzz for the first sec after PTT. And have some faith in your fellow vapers they can handle a pot they are DIY people.

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## johan (27/4/15)

Xhale said:


> I dont quite know how the numbers would stack up. I firmly believe its a fantastic idea, but I cant decide where the lower limit should be.
> Unloaded, I would say 3.6v is a battery I would consider putting back on charge.
> loaded? as mentioned above, it really does depend on the load. A 0.5ohm coil at 16w or so is 2.8volts. I tended to vape around there on a sig100. So if that is the lower range, and members here want 3.4v or 3.7v then it'll be tough to design something static to cater for all users. Perhaps a small variable resistor would do the job...vape till you arent happy anymore, then set the pot such that the light changes and that is your setting. Pot range for light to go from red to green would be somewhere from 2.8v to 3.6v. Dirty contacts arent an issue, but different cells will drop a different amount when fired, so...ja...a variable resistor pls so we can set our own. You get those small surface mount ones that you need an itty-bitty screwdriver to adjust.



Thanks for your comments and I do agree, but as I explained to a poster above; *"*I've learned over the years to NOT provide the end-user with an adjustable pot (especially surface mount pots), they WILL break it".


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## Xhale (27/4/15)

the little pager motors would work..they have an offset weight to create vibration. Silent enough not to distract anybody, and the buzzing in your mod will alert you.

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## Necris (27/4/15)

@6ghost9 ,@CYB3R N1NJ4


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## FireFly (27/4/15)

Seems like a lot of trouble all this.. Get a Regulated Mod LOL

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## free3dom (27/4/15)

I love the idea @johan and as a Neonaut I'm still getting to grips with using a device without a battery indicator - although using the amount of juice as an indicator is pretty accurate, but when swapping bottles halfway through one I do get very confused 

I would definitely go for one of these, as per your original description - simple but effective design, well done 

Edit: I also change the battery at around 3.7V (no load).

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## jtgrey (27/4/15)

@johan put me on the list as well. The only thing that i would say is instead of a red and green led . Why not just a green or just a red . If green go out you know to change battery or no green and only red that comes one when flat . 

Personally i would prefer only a red that comes on when flat seeing that when i drive at night it will be very annoying if the green comes on every time a vape .

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## Silver (27/4/15)

Hi @johan

Great to see the makings of another "@johan" doohickey!

When I change batteries, my battery generally measures around 3.7V (when taken out of the Reo). That seems to be the point at which I prefer to switch to a new battery. 

If it helps you, I have done voltdrop tests across all my Reos on a few occasions. My coil resistances vary from about 0.5 to 1.0 ohms. The voltdrop measured under load (at the coil posts when firing, with a wicked juice) has always varied between 0.20 V and 0.30 V. I think I have gotten a 0.18V once, but its usually around 0.25V. This has been using Efest purple 18650 2500 mah flat tops and Efest red 18490 1100 mah nipple tops all of the same age and approximately the same number of charge/drain cycles each. I did one or two tests when all my kit was fairly new and another one about 3 or 4 months ago and another one a few weeks ago. The voltdrop outcomes have been similar on all occasions. 

So if you want a lower cutoff under load to mimic the 3.7V (outside reading) I like to change batts at, I would say 3.4 to 3.5V is the region for your device's red light. Probably 3.5V to err on the side of caution.

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## andro (27/4/15)

i like the idea as well .sound excellent for me .

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## johan (27/4/15)

jtgrey said:


> @johan put me on the list as well. The only thing that i would say is instead of a red and green led . Why not just a green or just a red . If green go out you know to change battery or no green and only red that comes one when flat .
> 
> Personally i would prefer only a red that comes on when flat seeing that when i drive at night it will be very annoying if the green comes on every time a vape .



Thanks for your comments, I think we are a few already that only requires attention only when the battery needs to be replaced. I will design an option in to have either or.

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## johan (27/4/15)

Silver said:


> Hi @johan
> 
> Great to see the makings of another "@johan" doohickey!
> 
> ...



Thanks for your input I really do appreciate it. 99% of all Li-ion and Li-po batteries are safe down between 2.5Vmin and 3.0V according to various data sheets. I personally think and on load detection voltage round 3.2 to 3.5V should cater for most (some of us have quite long toots ).

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## johan (28/4/15)

Been looking at some components to use, and at the same time to keep it as simple-stupid-possible. This is the first idea, utilizing an industry standard voltage supervisory IC (Texas Instruments: TPS3809K33) mainly used for DSP's and processor based systems.

As said previously it will be an "Open Hardware" design (CERN _Open Hardware_ License). Here is the proposed schematic and a quick graphic of the pcb layout. I don't have access to a Reo mini and it will be appreciated if someone can confirm whether a 14mm wide pcb will fit behind the juice bottle on same?





​PS: Any other techies on this forum?, you are welcome to chime in (schematic, layout, B.O.M available for free, just send me a pm), after all its OSHW.

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## ShaneW (28/4/15)

Nice neat design! 

Out of curiosity... Does the zener not require a voltage divider resistor network to set the voltage? 
Circuit design is not my field of expertise, I've never even worked with a 3 pin zener so interested to understand the operation. My understanding was that it requires a resistor network to determine its bias voltage?

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## johan (28/4/15)

ShaneW said:


> Nice neat design!
> 
> Out of curiosity... Does the zener not require a voltage divider resistor network to set the voltage?
> Circuit design is not my field of expertise, I've never even worked with a 3 pin zener so interested to understand the operation. My understanding was that it requires a resistor network to determine its bias voltage?



Shane its not a zener diode as such, its a "voltage supervisor" integrated circuit (IC) and in essence it works as follows:

During power-on, RESET (the 3'rd pin) is asserted when the supply voltage becomes higher than 1.1V on pin 1 (_pin 2 referenced to ground_). Thereafter, the supervisory circuit monitors supply voltage and keeps the RESET pin active as long as the supply voltage remains below the threshold voltage. An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. The delay time, 200ms, starts after the supply voltage has risen above the threshold voltage. When the supply voltage drops below the threshold voltage, the output becomes active (low) again. No external components are required. All the devices of this TPS8902 family have a fixed sense-threshold voltage set by an internal voltage.

Hopes this explains it.

Reactions: Thanks 1 | Informative 2


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## JW Flynn (28/4/15)

my dad would probably have been the perfect guy to help with this, but he is not a smoker / vaper, and he is PC illiterate... it's a good thing if I can get him to bloody read his mail, LOL

Other than that, he is in the two way radio business and building / modifying all sorts of weird and wonderful stuff.. but urg, just trying to get him onto this forum, and read never mind type something would be a mission!! LOL... i'm sure you will probably get all the help you need 

One thing I need to mention.... with the RC heli's you actually get a little device that plugs in on your batteries ( usually use it when you suspect a degrading performance battery, to make sure the battery keeps withing expected limits) it simplu plugs in on your battery, and monitors the voltage on the battery, you can set the required voltage and the thing has a light and an VERY loud alarm ( you need to hear it while your chopper/drone/plain is flying, so trust me this thing is loud!!!! but i'm sure you can disable (solder the horn off) and use it for what you are trying to do here... plus it has the added benefit of allowing you to choose the voltage it witch it alerts you... 

on this note, be warned, as with the heli's while doing some 3D flying and the motor working a bit harder, it does dip below the set voltage but then again the voltage normalizes after, the same would happen with you using it on your mod.. it will dip probably depending on your build to below the set voltage, showing the alarm, but will normalize again after... so when the normalized voltage is reach while not firing, then you need to change your battery... not before or you will end up with a bunch of half used batteries when you get to your charger...  (remember, your battery charges up to 4.2 volts but it's nominal voltage (where you will be using it for the longest time and it's comfort range) is 3.7 Volts (well that is for most of the 18650's and 26650's i have seen)

Below is a picture of the device i'm talking about... if memory servers the battery checker is in the range of 50 - 80 Rands... so not a train smash... perhaps take a look at these devices before going to far into creating your own one...

Let me know what you think

The tester that I have comes in a small casing as you can see, i'll give you the different angles, the top


The side with the horns..


The side with the connectors (works from one cell batteries up to 9)


Image of the top side, removed from it's casing


and the bottom of the tester, when removed from the casing


In the video demonstrating it working.. you will note that it counts from cell one and it's voltage right up to cell 6 with it's voltage and then it has "all" this is because this is a 6 cell battery... the less cells the battery has then it only shows those cells... 

Check it out and see if this can possibly already fulfill your needs... and with an added bonus of a nice LCD display, plus, you can even use it on box mods with more cells, so it will even show you that

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## ShaneW (28/4/15)

johan said:


> Shane its not a zener diode as such, its a "voltage supervisor" integrated circuit (IC) and in essence it works as follows:
> 
> During power-on, RESET (the 3'rd pin) is asserted when the supply voltage becomes higher than 1.1V on pin 1 (_pin 2 referenced to ground_). Thereafter, the supervisory circuit monitors supply voltage and keeps the RESET pin active as long as the supply voltage remains below the threshold voltage. An internal timer delays the return of the output to the inactive state (high) to ensure proper system reset. The delay time, 200ms, starts after the supply voltage has risen above the threshold voltage. When the supply voltage drops below the threshold voltage, the output becomes active (low) again. No external components are required. All the devices of this TPS8902 family have a fixed sense-threshold voltage set by an internal voltage.
> 
> Hopes this explains it.



Aaaah Ok, that makes sense. Thanks for the explanation.

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## ShaneW (28/4/15)

Just an idea... How much extra would it cost to encapsulate the pcb in resin? Just concerned about juice leakage

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## kimbo (28/4/15)

@johan love your design, must confess my very limited limited knowledge is for a higher current. I was thinking about the LED colors, is the green and red color set i stone or will you allow for options later? I think blue will look awesome with the black Reo and then red to tell you it is time

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## kimbo (28/4/15)

ShaneW said:


> Just an idea... How much extra would it cost to encapsulate the pcb in resin? Just concerned about juice leakage



Will hot glue work?


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## johan (28/4/15)

JW Flynn said:


> my dad would probably have been the perfect guy to help with this, but he is not a smoker / vaper, and he is PC illiterate... it's a good thing if I can get him to bloody read his mail, LOL
> 
> Other than that, he is in the two way radio business and building / modifying all sorts of weird and wonderful stuff.. but urg, just trying to get him onto this forum, and read never mind type something would be a mission!! LOL... i'm sure you will probably get all the help you need
> 
> ...




Thanks for your input, yes I know these types and have about 20 of them in clear heatshrink (so if you need some just let me know - pic below). It would be wonderful if your dad can chime in.

Regarding the voltage "dipping"; exactly why I select the TPS8902 family of IC's - build in 200ms delay and the alert will only come on when the battery under load (dipping state), gets below i.e +/- 3.2V (I still need to do some tests to determine the average "dipping" voltage). The "idea" circuit is only active when the firing button is pressed.

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## johan (28/4/15)

kimbo said:


> @johan love your design, must confess my very limited limited knowledge is for a higher current. I was thinking about the LED colors, is the green and red color set i stone or will you allow for options later? I think blue will look awesome with the black Reo and then red to tell you it is time



I think once the design is finalized we should do a poll and decide, but at this stage Red & Green are only used for example purposes - we can do basically any of the following colors:

Red
Green
Blue

White
Yellow
Amber
Those that have access to soldering irons/stations, its easy to remove and replace with another color LED. PS: SMD's (surface mount devices) are easy to de-solder/solder with an ordinary soldering iron and you don't need fancy equipment.

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## ShaneW (28/4/15)

johan said:


> SMD's (surface mount devices) are easy to de-solder/solder with an ordinary soldering iron and you don't need fancy equipment.



Unless you have Parkinsons

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## johan (28/4/15)

kimbo said:


> Will hot glue work?



Hot snot will work kimbo.

I intend, if the idea comes to fruition, to conformal coat the pcb. We use that in the industry to protect pcb's against moisture, corrosion etc. In fact the pcb (and all the components) are waterproof once properly conformal coated.

Epoxy is expensive and you need a little mould plus vacuum pump to do correctly.

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## ShaneW (28/4/15)

Bought one of these last week... Very impressed. The SMD iron works beautifully on SMD's 

http://www.magnumproducts.co.za/2006.html

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## johan (28/4/15)

ShaneW said:


> Just an idea... How much extra would it cost to encapsulate the pcb in resin? Just concerned about juice leakage



I intend, if the idea comes to fruition, to conformal coat the pcb. We use that in the industry to protect pcb's against moisture, corrosion etc. In fact the pcb (and all the components) are waterproof once properly conformal coated. Epoxy is expensive and you need a little mould plus vacuum pump to do correctly.

Reactions: Like 1 | Informative 1


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## johan (28/4/15)

ShaneW said:


> Bought one of these last week... Very impressed. The SMD iron works beautifully on SMD's
> 
> http://www.magnumproducts.co.za/2006.html



Nice and a good quality local brand, for SMD's I use a re-flow oven except on proto-types where I use hot air. My soldering station of choice is Weller. (Hakko is also a nice budget soldering station brand).

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## johan (28/4/15)

Thanks for the suggestion @kimbo, @Rob Fisher also did a similar suggestion: BLUE instead of GREEN



​

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## kimbo (28/4/15)

@johan suggestion, what will it take to keep the LED on for say 0.5 seconds after the fire button is de-pressed, some of us vape with the door away from eye sight and you will not see the light unless you press the fire button to look. When you put it down and see your Reo glowing red you know it is time, but if you dont see the red, you have to consciously press the button to see what color is glowing.
I think after a few glasses of OJ you will not think to press the button, just a thought.

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## Jimbo (28/4/15)

I only saw this thread now, but you can count me in as well @johan

I have also many times vaped a battery to death when overindulging so this will be awesome.

3.7 V for me as well

Just one question, will one notice the light when you've overindulged?
Shouldn't one build in a "shocking" mechanism for this purpose? 
(Just kidding, your 'light' idea is great)

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## johan (28/4/15)

kimbo said:


> @johan suggestion, what will it take to keep the LED on for say 0.5 seconds after the fire button is de-pressed, some of us vape with the door away from eye sight and you will not see the light unless you press the fire button to look. When you put it down and see your Reo glowing red you know it is time, but if you dont see the red, you have to consciously press the button to see what color is glowing.
> I think after a few glasses of OJ you will not think to press the button, just a thought.



It is remarkable how the juice bottle diffuses a LED light, you will see it in your periphiral vision. The extra 500ms can be done, but its extra components (will see how much extra time can be achieved with a small capacitor when I do proto-typing).

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## kimbo (29/4/15)

Efest 2500 35amp

Battery change

no load = 3.8v

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## ShaneW (29/4/15)

Purple Efest 3100mah 20A

Running a 0.8ohm coil 

No load - 3.68V
Loaded - 3.50V

This seems consistent with @Silver findings

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## Keyaam (29/4/15)

Im in as long as it will fit in the reo mini


Sent from my iPhone using Tapatalk


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## johan (29/4/15)

Keyaam said:


> Im in as long as it will fit in the reo mini
> 
> 
> Sent from my iPhone using Tapatalk



Please do me a favor (_requested before without any response_): measure the width between side wall and divider (where the bottle normally sits), I will appreciate it and be able to confirm if it will fit or not. Thanks.


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## Keyaam (29/4/15)

johan said:


> Please do me a favor (_requested before without any response_): measure the width between side wall and divider (where the bottle normally sits), I will appreciate it and be able to confirm if it will fit or not. Thanks.


Width is 15mm


Sent from my iPhone using Tapatalk

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## johan (29/4/15)

Keyaam said:


> Width is 15mm
> 
> 
> Sent from my iPhone using Tapatalk



Thanks, I really appreciate, the pcb is only 14mm wide max, so it will fit in a Reo mini.

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## CRcranky (29/4/15)

Does it really need an LED to indicate battery fine though ? would a single battery not fine indicator not only be cheaper but also easier and smaller to manufacture. After all that is the only one you are interested in


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## devdev (29/4/15)

I was wondering the same as @CRcranky last night.

What if we substituted the green LED for a "black LED" . It is only necessary to see a light warning that things are not well, we know if we take a toot and the device doesn't work then there is something wrong with it.

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## CRcranky (29/4/15)

or just leave it out completely would almost cut the circuit in half meaning smaller in size and easier and cheaper to manufacture


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## BumbleBee (29/4/15)

CRcranky said:


> or just leave it out completely would almost cut the circuit in half meaning smaller in size and easier and cheaper to manufacture


Now where's the fun in that? Some may not admit it but I think everyone secretly desires little gadgets that glow and blink

Reactions: Agree 1


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## johan (29/4/15)

CRcranky said:


> Does it really need an LED to indicate battery fine though ? would a single battery not fine indicator not only be cheaper but also easier and smaller to manufacture. After all that is the only one you are interested in



I tried very hard to understand your post, but must admit I am stupid, and you need to elaborate better for me to understand ?

It seems, correct me if I am wrong, that you suggest a: 'battery OK only' indicator?


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## Philip Dunkley (29/4/15)

@johan, you want me to come round with the Mini for measurements?

Cheers


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## johan (29/4/15)

Philip Dunkley said:


> @johan, you want me to come round with the Mini for measurements?
> 
> Cheers



If you feel like it, come over for a beer or .....  Just remind me to take measurement before you leave.

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## devdev (29/4/15)

CRcranky said:


> Does it really need an LED to indicate battery fine though ? would a single battery not fine indicator not only be cheaper but also easier and smaller to manufacture. After all that is the only one you are interested in



Ohm @johan what I think @CRcranky is saying is that the green light could be unnecessary. The doo-hickey that you are currently making shows a green light if the battery is fine, and a red light if it is not fine. The question asked by Crcranky is "Do we need the green light?" I was thinking the same last night.

What the doo-hickey is supposed to do is warn you about a battery that is very low. My comment earlier: if you fire the Reo and vape, and nothing happens, then you know something is wrong with your setup. There isn't really much that the green light does, other than to tell you the voltage is above a certain threshold.

Take away the green light (hence why I said, swop it for a 'black' LED ). Now we have a red light only. If it is off, then the battery is fine. If the red lights up (Red = dead) then you have a battery below the threshold, no Red means you can carry on vaping and consuming six packs of fruit juice, until the red light does come on.

Unless I am wrong, I don't see much benefit from having a green light...

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## kimbo (29/4/15)

devdev said:


> Ohm @johan what I think @CRcranky is saying is that the green light could be unnecessary. The doo-hickey that you are currently making shows a green light if the battery is fine, and a red light if it is not fine. The question asked by Crcranky is "Do we need the green light?" I was thinking the same last night.
> 
> What the doo-hickey is supposed to do is warn you about a battery that is very low. My comment earlier: if you fire the Reo and vape, and nothing happens, then you know something is wrong with your setup. There isn't really much that the green light does, other than to tell you the voltage is above a certain threshold.
> 
> ...



I would love a weird blue glow reo

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## johan (29/4/15)

devdev said:


> Ohm @johan what I think @CRcranky is saying is that the green light could be unnecessary. The doo-hickey that you are currently making shows a green light if the battery is fine, and a red light if it is not fine. The question asked by Crcranky is "Do we need the green light?" I was thinking the same last night.
> 
> What the doo-hickey is supposed to do is warn you about a battery that is very low. My comment earlier: if you fire the Reo and vape, and nothing happens, then you know something is wrong with your setup. There isn't really much that the green light does, other than to tell you the voltage is above a certain threshold.
> 
> ...



Read the feckin OP! I love red lights when I had too much Oros .

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## free3dom (29/4/15)

While I agree that the "battery fine" light could be omitted, there is one caveat to that - you won't be aware if the circuitry fails (for whatever reason) and could, if "oros-ed" enough, vape your battery to death because you are waiting for the red light that never comes

Reactions: Agree 1


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## johan (29/4/15)

free3dom said:


> While I agree that the "battery fine" light could be omitted, there is one caveat to that - you won't be aware if the circuitry fails (for whatever reason) and could, if "oros-ed" enough, vape your battery to death because you are waiting for the red light that never comes



I agree, the quality of "oros-ed" enjoyment have to be the solace to such an unfortunate event . I'm off to such an compulsory event ATM .

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## Keegan (1/5/15)

An option is to use the RGB LED SMD for 3 possibilities:
> 3.7V == Green
> 3.2V == Blue (& < 3.7V)
< 3.2V == Red
Choose colors and voltage levels as desired.
Though prob cannot use the TPS chip, maybe revert to Zener diode + comparator IC, not sure if SMD form factor exists plus adds more components (and maybe tolerances of components does not allow for such an approach)...?

Voltage range allows for standardized approach, especially if devices will be sold...and takes care off multiple load issues, perhaps?

Taken further, use RGBC SMD,
with white for reverse polarity of battery, tho white needs to be hard coded to battery (bypassing switch).
Current draw (power dissipation) may also be higher with zener+comparator.


Sent from the moon of Jupiter

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## johan (1/5/15)

Keegan said:


> An option is to use the RGB LED SMD for 3 possibilities:
> > 3.7V == Green
> > 3.2V == Blue (& < 3.7V)
> < 3.2V == Red
> ...



Like your suggestions very much, but I would like to stay away in this instance from micro processors.


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## hands (4/5/15)

i like the idea that when you vape the light is off but i don't like the flashes

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