ULTIBOX : Ecig Boost mod with lcd screen , 18650, Constant power. OPEN SOURCE
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Palipoe, I thought you left, watched your old vid's and always wondered when you will be back, good to see and all the best, looks promising!!!
Wow, thanks for all the replies, that was generous of you, again.
Oops, yea 5k, not 50k.
I only did a quick look at the data sheet. I see that now. That's good then.
Well, simulations are simulations. I'd check that on the bench.
550kHz with 200u, 680kHz with 100u. Problem is that efficiency drops as frequency goes up. Don't want to run it any higher than I need to. My simulations tell me I can run lower value output caps, but simulations don't account for all factors. I usually get around double the output ripple when measured on the scope compared to the simulation. But hey, if it works, then great. My concern is destabilizing the controller with excessive ripple and also the noise it generates.
True there is an amount of power transfer going on through the caps and atomizer, but all of the input ripple and converter startup transients return through the ground plane to battery negative. That's a considerable amount of cross inductance for any traces above it. I would not run a shared plane, but if you say you have no issue, then great.
I don't see that regulator in the schematic, where is that thing? Am I blind or something?
I don't understand the purpose of D1. If it's connected to USB power, then it's not a clamp to protect against a USB over-voltage condition. What does it do?
Yes, I see the newer PICs have that feature. I haven't used any of the most recent ones. The PIC24Fs I've been I'm using and the PIC18Fs I've used before that do not have an internal voltage reference. Even so, I mistakenly assumed the current sense resistor was 10mΩ in my last post. I see it's 100mΩ giving you good resolution and range with that voltage reference. That's good for sensing, but you're taking a big power hit using a current sense resistor with such a high value.
Like I said before, you seem to be liberal with efficiency. 17mΩ is high, but insignificant compared to other resistive losses in your circuit. The one I'm using is 6mΩ.
Ideally, a device should be able to sit on the shelf for a long period of time without critically discharging the battery. Keep in mind I'm using a non-removable LiPo cell. My worst case is a low battery sitting on the shelf for several months. 10uA provides a generous period of time without without over-discharge. I'm sure there are other ways to handle it, but you also don't want to waste power when the device is idle. That reduces run time. Kills two birds with one stone that way.
That's kind of sketchy. If you have a short and sensing fails, you'll have current limited only by the resistance of the circuit. Being liberal, that's not more than 300mΩ. With a fully charged batt, that's a load of 14A, an over-current condition for an IMR 18650.
With the resistive losses in my design and the ultra-low DCR LiPoly cell, I get a worst case of around 80A with a direct atomizer short. I have to have a fuse. It's not optional.
I wouldn't be very happy if I posted my whole design to help other DIY modders then found some part of it in a commercial product where someone used the sweat off my back or my ideas to save themselves some work and make a profit. This has happened several times already in this forum. That bothers me a lot. If you don't care about it, that's good for you. That must be the case or you would not have posted your design.
Thanks again for your replies.
Oops, yea 5k, not 50k.
I only did a quick look at the data sheet. I see that now. That's good then.
Well, simulations are simulations. I'd check that on the bench.
550kHz with 200u, 680kHz with 100u. Problem is that efficiency drops as frequency goes up. Don't want to run it any higher than I need to. My simulations tell me I can run lower value output caps, but simulations don't account for all factors. I usually get around double the output ripple when measured on the scope compared to the simulation. But hey, if it works, then great. My concern is destabilizing the controller with excessive ripple and also the noise it generates.
True there is an amount of power transfer going on through the caps and atomizer, but all of the input ripple and converter startup transients return through the ground plane to battery negative. That's a considerable amount of cross inductance for any traces above it. I would not run a shared plane, but if you say you have no issue, then great.
I don't see that regulator in the schematic, where is that thing? Am I blind or something?
I don't understand the purpose of D1. If it's connected to USB power, then it's not a clamp to protect against a USB over-voltage condition. What does it do?
Yes, I see the newer PICs have that feature. I haven't used any of the most recent ones. The PIC24Fs I've been I'm using and the PIC18Fs I've used before that do not have an internal voltage reference. Even so, I mistakenly assumed the current sense resistor was 10mΩ in my last post. I see it's 100mΩ giving you good resolution and range with that voltage reference. That's good for sensing, but you're taking a big power hit using a current sense resistor with such a high value.
Like I said before, you seem to be liberal with efficiency. 17mΩ is high, but insignificant compared to other resistive losses in your circuit. The one I'm using is 6mΩ.
Ideally, a device should be able to sit on the shelf for a long period of time without critically discharging the battery. Keep in mind I'm using a non-removable LiPo cell. My worst case is a low battery sitting on the shelf for several months. 10uA provides a generous period of time without without over-discharge. I'm sure there are other ways to handle it, but you also don't want to waste power when the device is idle. That reduces run time. Kills two birds with one stone that way.
That's kind of sketchy. If you have a short and sensing fails, you'll have current limited only by the resistance of the circuit. Being liberal, that's not more than 300mΩ. With a fully charged batt, that's a load of 14A, an over-current condition for an IMR 18650.
With the resistive losses in my design and the ultra-low DCR LiPoly cell, I get a worst case of around 80A with a direct atomizer short. I have to have a fuse. It's not optional.
I wouldn't be very happy if I posted my whole design to help other DIY modders then found some part of it in a commercial product where someone used the sweat off my back or my ideas to save themselves some work and make a profit. This has happened several times already in this forum. That bothers me a lot. If you don't care about it, that's good for you. That must be the case or you would not have posted your design.
Thanks again for your replies.
I ordered 5 pcbs for my tests , I will test and adjust value on these boards. I also redesigned my ground plane by rotating the screen. The plan is much more clear.
For the fuse, I can always add one later.
There will be a lot of work on the software later.
Making public my work does not bother me, everyone copies everyone. In addition, there is nothing special
.
For the fuse, I can always add one later.
There will be a lot of work on the software later.
Making public my work does not bother me, everyone copies everyone. In addition, there is nothing special
.It's nothing special from an EE's standpoint, but it is special in that not many people could design something like that from the ground up. They'd either need to gain a good amount of knowledge or pay a good amount of money to have engineering firm design it for them.
I came in here 'cos of the words "OPEN SOURCE", but this is far more than I'd expected. Very very promising design. Kinda like an open source Darwin. My only real hurdle is that I don't have much experience with etching my own PCBs, but this is intriguing enough that I might just have to learn. I'm having some ideas how to extend the functionality of the Darwin, but this would be far simpler (not to mention less expensive) to build.
Thanks very much!! Subscribed.
Thanks very much!! Subscribed.
What power range / volt range do you expect most people to use, 20W seems high?
What sort of vape time are you expecting or getting?
Recharge seems like it would be a lengthy process
I have a couple of variable power mods from an Aussie maker, at 9 to 10.5 watts on a 2 ohm carto I get around 7 MLS from the one with 2 x 1000mah lipo batteries, these are recharged with an onboard balanced and protected charger in half an hour. At the end of the day these are the things that matter to me I guess, but your screen is cool.
What sort of vape time are you expecting or getting?
Recharge seems like it would be a lengthy process
I have a couple of variable power mods from an Aussie maker, at 9 to 10.5 watts on a 2 ohm carto I get around 7 MLS from the one with 2 x 1000mah lipo batteries, these are recharged with an onboard balanced and protected charger in half an hour. At the end of the day these are the things that matter to me I guess, but your screen is cool.
max charging current (USB) : 500mA
Time for full charging (1600mA.h) : 4-5h max
Voltage range (output) : 3-10v (need to be adjust on prototype).
Iinput max : 6-7A
This needs to be adjusted on my prototypes based on the maximum heat dissipation, efficiency ...
Time for full charging (1600mA.h) : 4-5h max
Voltage range (output) : 3-10v (need to be adjust on prototype).
Iinput max : 6-7A
This needs to be adjusted on my prototypes based on the maximum heat dissipation, efficiency ...
Please post a bunch of pics when you get the first one together! I cant wait to see it in action.
...hope you got your order out for your proto boards today. ...continued encouragement offered on your project. ...hope you are indeed able to offer 'kit of parts' for developers and users.
Nice work Pailipoe...
I was a little discouraged when I didn't see you for a while...I was quite impressed with the modulra project...this one looks spectacular...keep up the good works ...glad to see you back...
I was a little discouraged when I didn't see you for a while...I was quite impressed with the modulra project...this one looks spectacular...keep up the good works ...glad to see you back...
like a fat Ipod! I would incline more to a longer skinny type of box, but nice done Dan!
Looks like pailpoe is planning for a 18650. If so box would have to be a little chunky.
Dan it looks like display and switches down and battery up would be more appropriate
but what if it has a rotating disc on the front to dial in the wattage and click on it to vape!!!
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