Flotsam
Well-Known Member
curious if you have any estimates for power consumption?
so the PWM switching is all handled by the Pico board?
Was there existing code that you could make use of?
Nice job, this is fun to watch.
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Unregulated simple all glass vape
- Thread starter highvaper
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so the PWM switching is all handled by the Pico board?
Was there existing code that you could make use of?
Nice job, this is fun to watch.
highvaper
Well-Known Member
Not just estimates - real time power consumption now - there is a live volt reading and knowing the restance of the element it works it out live - quite cool to watch it adjust power in watts and not the arbitrary level of 0 to 10 for the pwm - there is now a temp/watt graph
Yea all regulation is handled by the rp2040 - the actual power is controlled by a separate mosfet circuit - i wanted to keep this separate as it then allows the board to be used with solid state relays, normal relays and switched stuff.
I used some libraries for some hardware like the display, rotary dial and the simple pid library to do the maths.
Take a look at the repo on github its all available for people to use if they want - i have added some updates recently and will add more soon as i have already added some bits for the new leds.
Flotsam
Well-Known Member
Excellent job! congrats , Maybe i missed it but do you have the github link?
ooh ooh I want next hit!
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XpeeN
Well-Known Member
Great job and nice documentation! I really enjoyed reading this.
Any reason you choose rp over an esp32? It might be enough for your project
highvaper
Well-Known Member
I had a bit of experience with full blown pi's when i started the project off and someone at work i chatted with was a bit of a pico fan so have kind of just rolled with it - the documentation out there is really good too so that always helps.
I suspect if i started from scratch i would probably go down the esp32 route now but there isnt much difference between them for my needs - the esps are a bit faster but the pico has the pio instances which can be super fast (so far not needed to use them for this though).
Wifi/bluetooth on board would be useful for other things but for a vape the last thing i want to do is tie it to a mobile with bluetooth.
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highvaper
Well-Known Member
Sure its on the other thread but here you go:
GitHub - highvaper/heater-controller: MicroPython RP2040 Heater Controller
MicroPython RP2040 Heater Controller. Contribute to highvaper/heater-controller development by creating an account on GitHub.
github.com
highvaper
Well-Known Member
Was going a bit mad and went for 4 lipos - test 1 was good
So decided to just film the screen on test 2
Gutted already killed one but this happened before with the normal pico and i wasnt sure what went wrong this time im sure the coil just burnt through the ptfe and shorted out the thermocouple so the unit got 16v into the thermocouple and the rest of the board. Its dead - good thing i got a few.
Ok to be fair pushing over 300W may not have been the best idea - if you look closely in the second video you can see a little bit of smoke near the mosfet - i cant locate where that actually came from as the mosfet unit is fine and is working still.
But good to know what to be careful of and what to improve upon so i think maybe to get some kapton/ploymide tape and fold a small piece around exposed the thermocouple parts and slide the ptfe over it so even if the ptfe gets burn through there is still an insulating layer.
So decided to just film the screen on test 2
Gutted already killed one but this happened before with the normal pico and i wasnt sure what went wrong this time im sure the coil just burnt through the ptfe and shorted out the thermocouple so the unit got 16v into the thermocouple and the rest of the board. Its dead - good thing i got a few.
Ok to be fair pushing over 300W may not have been the best idea - if you look closely in the second video you can see a little bit of smoke near the mosfet - i cant locate where that actually came from as the mosfet unit is fine and is working still.
But good to know what to be careful of and what to improve upon so i think maybe to get some kapton/ploymide tape and fold a small piece around exposed the thermocouple parts and slide the ptfe over it so even if the ptfe gets burn through there is still an insulating layer.
highvaper
Well-Known Member
Finished off my desktop replacement - well more my general use device while i play about with better housing as its not tied the mains anymore.
The thermocouple cable is on the wrong side side need to rewire that but but otherwise is nice a neat and not a load of wires everywhere. Also only one mosfet as that has been fine for the desktop at about 100W so will see how it goes.
Mains powered
4 Lipos - i do like using it with 3 so going to try with 4 and just limit the power so the element doesnt get hot enough to burn the ptfe.
2 Lipos - for on the go
Been doing a bit of research re protecting the circuit board should the element get too hot again and burn through.
There are TVS Diodes which can basically act like a fuse and shunt any too high voltage straight to ground. Just doing a bit more digging to make sure they will work with the thermocouple. So there should be the extra physical barrier with the polymide tape protection and also electrical one. I should be able to retro fit the TVS diode to the existing boards pretty simply by just connecting one across the thermocouple leads at any point.
The thermocouple cable part needs to be easy to replace as it is one bit which can gt damaged and are pretty cheap/simple to replace - also the heater element i think needs to be serviceable and not bonded/welded to the housing - i did think about maybe some silver braising so connect it together or crimps but the screw physical connectors may be the best option.
Need to just remember to check on how the thermocouple protective ptfe is holding out - so far on the original glass version which has been my daily desktop driver i havent had any issue - its only been connected to the mains supply and limited between 100-120W so dont think has got anywhere near hot enough - the nichrome is still a shiny silver and not discoloured with heat.
Really need to code up profiles as switching between the different voltages/power types makes tuning the pid impossible.
Have discovered the power supply isnt stable - without load its 12.3v and then loaded starts at 12.3v drops to 8.1-8.5v for about 1/3 of the time so no wonder the pid tuning has been hard but it has been able to deal with it pretty well which im pretty chuffed about. Also the barrel connector is getting quite hot compared to the deans or other parts so i think i may snip it off and replace with a deans.
Once i redo the max wattage being a constant rather than the duty cycle percent so adjust the duty cycle on each voltage read so it can always output the max wattage at the current volts may improve it.
Graph of rubbish power supply:
The dotted line is the setpoint - the line which jumps is the watts - the other line at the bottom which rises is the temperature - the power is supposed to be max duty cycle but you can see it jumping about caused by the input volts jumping between about 8 and 12
The thermocouple cable is on the wrong side side need to rewire that but but otherwise is nice a neat and not a load of wires everywhere. Also only one mosfet as that has been fine for the desktop at about 100W so will see how it goes.
Mains powered
4 Lipos - i do like using it with 3 so going to try with 4 and just limit the power so the element doesnt get hot enough to burn the ptfe.
2 Lipos - for on the go
Been doing a bit of research re protecting the circuit board should the element get too hot again and burn through.
There are TVS Diodes which can basically act like a fuse and shunt any too high voltage straight to ground. Just doing a bit more digging to make sure they will work with the thermocouple. So there should be the extra physical barrier with the polymide tape protection and also electrical one. I should be able to retro fit the TVS diode to the existing boards pretty simply by just connecting one across the thermocouple leads at any point.
The thermocouple cable part needs to be easy to replace as it is one bit which can gt damaged and are pretty cheap/simple to replace - also the heater element i think needs to be serviceable and not bonded/welded to the housing - i did think about maybe some silver braising so connect it together or crimps but the screw physical connectors may be the best option.
Need to just remember to check on how the thermocouple protective ptfe is holding out - so far on the original glass version which has been my daily desktop driver i havent had any issue - its only been connected to the mains supply and limited between 100-120W so dont think has got anywhere near hot enough - the nichrome is still a shiny silver and not discoloured with heat.
Really need to code up profiles as switching between the different voltages/power types makes tuning the pid impossible.
Have discovered the power supply isnt stable - without load its 12.3v and then loaded starts at 12.3v drops to 8.1-8.5v for about 1/3 of the time so no wonder the pid tuning has been hard but it has been able to deal with it pretty well which im pretty chuffed about. Also the barrel connector is getting quite hot compared to the deans or other parts so i think i may snip it off and replace with a deans.
Once i redo the max wattage being a constant rather than the duty cycle percent so adjust the duty cycle on each voltage read so it can always output the max wattage at the current volts may improve it.
Graph of rubbish power supply:
The dotted line is the setpoint - the line which jumps is the watts - the other line at the bottom which rises is the temperature - the power is supposed to be max duty cycle but you can see it jumping about caused by the input volts jumping between about 8 and 12
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highvaper
Well-Known Member
Updated to deal with the fluctuating input voltage - i set the max watts to 80 and the max duty cycle gets adjusted accordingly to try and keep at the correct wattage no matter what the input voltage.
Should also compensate for battery sag but if you set the wattage too high for the voltage it will just max out at 100% which is as expected.
Is pretty annoying to find the two devices - the power meter and now the power supply both were not work working as i was expecting and possibly messed my calculations up for the past year.
Should also compensate for battery sag but if you set the wattage too high for the voltage it will just max out at 100% which is as expected.
Is pretty annoying to find the two devices - the power meter and now the power supply both were not work working as i was expecting and possibly messed my calculations up for the past year.
highvaper
Well-Known Member
Well im confused - im testing with the 4 lipo battery setup and max watts at 90w - 3 or 4 lipos is pretty sweet for on demand - with 4 the batteries just get a bit warm after a while and lasts for ages between recharges.
With 3 lipos - they do get a bit warm with back to back session not fully tested how many 5 min sessions from cold start you get from a charge nor how many on demand straws either but its way more than the tm2 or mighty+ can do.
One oddity im now thinking maybe the setup of the circuit board somehow - when it sits with the heater off the input voltage is constant but when the heater is on it does fluctuate like it did for the mains power source so am thinking there is some capacitor somewhere which is charging/discharging and affecting the reading somehow - i have checked the battery voltage with an old school analogue volt meter and its pretty stable and doesnt drop 2v suddenly - need to test with my digital one too - just been too busy with testing the vape part of it
I know there are bugs with the adc stuff on the rp2040 so maybe it could be that - need to dig into that and perhaps apply some filtering to the voltage reading as i had to do with the thermocouple and the induction heater. I do have the other version with the pico and an external voltage divider i can test with too so will give that a go and see if i can reproduce the issue there.
edit; Yup is the rp2040 https://forums.raspberrypi.com/viewtopic.php?t=354736
will have to code around it and check reading isnt too far off previous one and retry if it is so the capacitor gets a chance to recharge.
With 3 lipos - they do get a bit warm with back to back session not fully tested how many 5 min sessions from cold start you get from a charge nor how many on demand straws either but its way more than the tm2 or mighty+ can do.
One oddity im now thinking maybe the setup of the circuit board somehow - when it sits with the heater off the input voltage is constant but when the heater is on it does fluctuate like it did for the mains power source so am thinking there is some capacitor somewhere which is charging/discharging and affecting the reading somehow - i have checked the battery voltage with an old school analogue volt meter and its pretty stable and doesnt drop 2v suddenly - need to test with my digital one too - just been too busy with testing the vape part of it
I know there are bugs with the adc stuff on the rp2040 so maybe it could be that - need to dig into that and perhaps apply some filtering to the voltage reading as i had to do with the thermocouple and the induction heater. I do have the other version with the pico and an external voltage divider i can test with too so will give that a go and see if i can reproduce the issue there.
edit; Yup is the rp2040 https://forums.raspberrypi.com/viewtopic.php?t=354736
will have to code around it and check reading isnt too far off previous one and retry if it is so the capacitor gets a chance to recharge.
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highvaper
Well-Known Member
I think i have mostly fixed that bug with the hardware adc error and have coded around it.
A bit annoyed with myself as i dropped the heater/tube part and the lip hit the lid of a glass jar - the quarts was not as forgiving as the glass and a chip has been taken out of the top - it is still usable but i dont have that many of the outer tubes to break - if it was glass it would have completely broken so at least thats a bonus.
I may need to get some more - i have kind of reached a point with the build im a bit stuck with as currently i dont have access to a decent place to do any proper wood working nor space for a 3d printer so was chatting to one of the people i need to make one for and they said they would be happy with basic components and they would be happy to do something for themselves as they mostly want some desktop thing and dont care about batteries.
A bit annoyed with myself as i dropped the heater/tube part and the lip hit the lid of a glass jar - the quarts was not as forgiving as the glass and a chip has been taken out of the top - it is still usable but i dont have that many of the outer tubes to break - if it was glass it would have completely broken so at least thats a bonus.
I may need to get some more - i have kind of reached a point with the build im a bit stuck with as currently i dont have access to a decent place to do any proper wood working nor space for a 3d printer so was chatting to one of the people i need to make one for and they said they would be happy with basic components and they would be happy to do something for themselves as they mostly want some desktop thing and dont care about batteries.
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highvaper
Well-Known Member
So i have checked and all ok asking.
Would people be interested in a kit form of this like the vapoven diy kit?
Not sure on costing just yet as i need to know numbers before i can actually work out like getting 10 outer tubes/pcbs or 100 will be a big difference. It would include a variety of straws etc so not just the heater & pcb bits so basically the whole thing but no real housing.
If there is demand and i have time i could do a basic heater tube wood part like i currently have but suspect i wont have the time to do that many of them at the moment but can do a nice how to.
I have various ideas for housing/handles etc so would be good to see them get made if not by me or other peoples ideas too - i rekon you could make a superb looking log vape.
Would people be interested in a kit form of this like the vapoven diy kit?
Not sure on costing just yet as i need to know numbers before i can actually work out like getting 10 outer tubes/pcbs or 100 will be a big difference. It would include a variety of straws etc so not just the heater & pcb bits so basically the whole thing but no real housing.
If there is demand and i have time i could do a basic heater tube wood part like i currently have but suspect i wont have the time to do that many of them at the moment but can do a nice how to.
I have various ideas for housing/handles etc so would be good to see them get made if not by me or other peoples ideas too - i rekon you could make a superb looking log vape.