The Bud Toaster - (currently: Model 14, version 3)
- Thread starter Hippie Dickie
- Start date
understood ... but there's nothing new under the sun, really ... just a continuous stream of cosmic consciousness, swirling around and through us all.
Bubar
Well-Known Member
Yep... though I wonder what'll happen when weed gets legalized, since there are several patents on weed vaporizers and the us govt has a patent on medical marijuiana... http://www.patentstorm.us/patents/6630507.html
I guess once it's legal all vaporizer will admit their true uses and be used a prior art to throw out existing patents.
I guess once it's legal all vaporizer will admit their true uses and be used a prior art to throw out existing patents.
Bubar! How's it going? Did you see my posts where i fixed my PID implementation? (Pssst! want a hex file?)
Bubar
Well-Known Member
Sure a hex would be great. I'm always interested in the latest version. I don't know how much is the old algorithm or if its the difference in volts of power supply, but the current one doesn't work too great. I haven't been really using vape or working on building them.
I have 3 half working vaporizers. Each with different problems. I'm out of parts too. Pissing me off.
Do you ever get a problem where turning on the heater causes the pic to reset? happen's to me right now. I chopped out the transisor set up on that one, cuz I figure it must be shorted somehow.
Also on others the pwm ports will stop working.
I'm really tempted to do another pcb rev and use fresh parts to not deal with this kind of stuff. It's hard to know when admitting defeat is worth the time cost savings. You could learn something important from fixing something or just frustrate your self.
I have 3 half working vaporizers. Each with different problems. I'm out of parts too. Pissing me off.
Do you ever get a problem where turning on the heater causes the pic to reset? happen's to me right now. I chopped out the transisor set up on that one, cuz I figure it must be shorted somehow.
Also on others the pwm ports will stop working.
I'm really tempted to do another pcb rev and use fresh parts to not deal with this kind of stuff. It's hard to know when admitting defeat is worth the time cost savings. You could learn something important from fixing something or just frustrate your self.
i figured you had non-vape issues you were dealing with.
When i have a vape that fails i just throw it into "the drawer of broken vapes" and make a new one. i just got a complete set of parts for 5 more vapes and ordered 12 more batteries.
Once i figured out the correct layout for the MOSFET it has been steady progress forward. i have not experienced the problems you describe. Having a factory-made pcb has made a world of difference in moving this project forward. If the beta testing goes well i want to get the pcb already stuffed with surface mount components - shouldn't add that much to the cost and will greatly speed up fabrication -- although it only takes about an hour to stuff a pcb, but it is a pita when a resistor chip flys off the pcb and hits the floor -- they are so friggin' small.
HEX file is on its way. i also uploaded it to my SkyDrive on my Hot Mail account.
When i have a vape that fails i just throw it into "the drawer of broken vapes" and make a new one. i just got a complete set of parts for 5 more vapes and ordered 12 more batteries.
Once i figured out the correct layout for the MOSFET it has been steady progress forward. i have not experienced the problems you describe. Having a factory-made pcb has made a world of difference in moving this project forward. If the beta testing goes well i want to get the pcb already stuffed with surface mount components - shouldn't add that much to the cost and will greatly speed up fabrication -- although it only takes about an hour to stuff a pcb, but it is a pita when a resistor chip flys off the pcb and hits the floor -- they are so friggin' small.
HEX file is on its way. i also uploaded it to my SkyDrive on my Hot Mail account.
Yes, a change to SETPOINT is written to eePROM and used for subsequent sessions until changed again (via button press). COILTEMPtrip is also adjusted for the new SETPOINT to minimize overshoot on startup. DCBIAS is constantly written to eePROM during operation to adjust for battery pack voltage level.
These three values can be reset to "factory defaults" if it/they gets screwed up for some reason. Hold BUTTON2 at initial power up for 2 seconds, GREEN LED comes on, release BUTTON2 --- SETPOINT, COILTEMPtrip and DCBIAS are reset.
These three values can be reset to "factory defaults" if it/they gets screwed up for some reason. Hold BUTTON2 at initial power up for 2 seconds, GREEN LED comes on, release BUTTON2 --- SETPOINT, COILTEMPtrip and DCBIAS are reset.
status update ...
i've been spending a lot of time the last several days refining the software in and around the PID algorithm -- this is the code that enables the 1F temperature stability, regardless of volume or speed of the hit (and all in a 3" body -- actually all within the 1 1/2" of the heater tube).
i also found one horrendous bug where i was testing the limit of a value backwards -- fixed! And i added a bunch of macros that greatly simplify the way the algorithm appears -- much easier now to understand the logic flow and conditions.
The speed of temp increase has had me spooked (just a bit), but i think i've finally got it under control. And, remember when i reported that taking a hit caused the temp to rise just a bit to compensate? Well, i had lost that feature during the code rewrite ... but it's back!
That derivative term (the "D" in the "PID") is one powerful factor.
Finally, definitely, time put the code aside for a while and move on to finishing the 3rd unit ... i have a delivery date in 10 days.
i've been spending a lot of time the last several days refining the software in and around the PID algorithm -- this is the code that enables the 1F temperature stability, regardless of volume or speed of the hit (and all in a 3" body -- actually all within the 1 1/2" of the heater tube).
i also found one horrendous bug where i was testing the limit of a value backwards -- fixed! And i added a bunch of macros that greatly simplify the way the algorithm appears -- much easier now to understand the logic flow and conditions.
The speed of temp increase has had me spooked (just a bit), but i think i've finally got it under control. And, remember when i reported that taking a hit caused the temp to rise just a bit to compensate? Well, i had lost that feature during the code rewrite ... but it's back!
That derivative term (the "D" in the "PID") is one powerful factor.
Finally, definitely, time put the code aside for a while and move on to finishing the 3rd unit ... i have a delivery date in 10 days.
Purple-Days
Well-Known Member
Absolutely grand. I sometimes (mostly) have no idea what you speak of, but know for sure, it is energized and intelligent.
Right On !
Right On !
andrewburgess
Well-Known Member
It's a pleasure to find this thread and this project. I love the zero thermal mass design.
Is a protection circuit possible for when Q2 shorts?
For a fuse to work you'd need to only drive the transistor 80% (or something) max duty cycle so a short of 100% might blow the fuse. Or some sort of overtemp thermal cutout? Maybe make that copper bus bar out of lead so it'll melt (1/2). I know you can't really use lead but you catch my drift...something that melts when the inside temperature and/or current gets dangerous and interrupts current flow.
If you still have a drawer full of broken vapes you might rig one to simulate a shorted Q2 and see how bad it gets. I'm guessing fire. If you do this, please make a video!
Hope this is helpful.
PS It's too bad about losing all the early pictures. It does tend to make the thread seem broken and might stop some readers right before it gets interesting. Perhaps you could say at what post the pictures resume in the first post?
Cheers!
Is a protection circuit possible for when Q2 shorts?
For a fuse to work you'd need to only drive the transistor 80% (or something) max duty cycle so a short of 100% might blow the fuse. Or some sort of overtemp thermal cutout? Maybe make that copper bus bar out of lead so it'll melt (1/2
). I know you can't really use lead but you catch my drift...something that melts when the inside temperature and/or current gets dangerous and interrupts current flow.If you still have a drawer full of broken vapes you might rig one to simulate a shorted Q2 and see how bad it gets. I'm guessing fire. If you do this, please make a video!
Hope this is helpful.
PS It's too bad about losing all the early pictures. It does tend to make the thread seem broken and might stop some readers right before it gets interesting. Perhaps you could say at what post the pictures resume in the first post?
Cheers!
andewb - thank-you for your comments ... sometimes i think i'm just talking to myself ...
anyway, regarding your questions ...
i have never even considered the case where Q2 might short out (
)
When running at 440F, the dutycycle is about 128. to 160. (out of 1023. max), or about 12% to 15%. This is why this temperature control algorithm has been so difficult to get working -- that is, very tiny changes in duty cycle can really sling the temperature into a higher orbit. The algorithm actually just increments/decrements the duty cycle per update (1/3 of a second).
i do have an over temperature cutout in the software -- currently set for 550F. And there is a cutout for missing sensor or a sensor reading of zero (which can be caused by an open circuit from the MAX to the PIC) (i think).
And thanks for the failure mode test idea -- i needed something new to agonize over. The copper bus bar is 14 awg, so i think the 120 amps the batteries can deliver would melt it pretty good and quick without using lead. The shell of the vape body is 25 gauge stainless steel, so it can handle the temperature of a fire.
And of course you are right about the missing pictures ... i'll deal with that this morning (yet another good excuse for putting off a web design project for a little while).
anyway, regarding your questions ...
i have never even considered the case where Q2 might short out (
)When running at 440F, the dutycycle is about 128. to 160. (out of 1023. max), or about 12% to 15%. This is why this temperature control algorithm has been so difficult to get working -- that is, very tiny changes in duty cycle can really sling the temperature into a higher orbit. The algorithm actually just increments/decrements the duty cycle per update (1/3 of a second).
i do have an over temperature cutout in the software -- currently set for 550F. And there is a cutout for missing sensor or a sensor reading of zero (which can be caused by an open circuit from the MAX to the PIC) (i think).
And thanks for the failure mode test idea -- i needed something new to agonize over. The copper bus bar is 14 awg, so i think the 120 amps the batteries can deliver would melt it pretty good and quick without using lead. The shell of the vape body is 25 gauge stainless steel, so it can handle the temperature of a fire.
And of course you are right about the missing pictures ... i'll deal with that this morning (yet another good excuse for putting off a web design project for a little while).
andrewburgess
Well-Known Member
I'm sure the lurker to poster ratio is very high here. The registration process gets more difficult as blood THC levels riseHippie Dickie said:
I'm worried about the hand holding the caseHippie Dickie said:
A battery short might be way over 120A and I'd worry that stuff would vaporize explosively rather than melt.Hippie Dickie said:
I had thought a battery short would be unlikely but now it just occurred to me that a FET short could raise the temperature enough to melt all the insulation inside the case. That might allow a battery short. Yikes. You might want to test what happens in a battery short too but from a very large distance (like watch it on video distance).
Not to mention the batteries themselves. Does the manufacturer say what happens if you short one?
I'm probably just being an alarmist but a fuse would prevent all that.
Hey, it'll be fun. I bet fuses have a science all their own.
i kinda doubt a fuse could handle the current requirements - switching 12 amps on/off a thousand times a second???
Also, the stainless steel is wrapped with ceramic tape -- good for way over 1000F.
The spec sheet for the A123Systems batteries claims 120A max current for 15 seconds, 70A continuous ... when i have shorted the batteries (accidently) it is like putting a screw driver across the 120 AC line (which i've also done accidently) >>> sparks and etched metal.
The manufacturer does say the batteries don't explode or burn, due to the nanophosphate construction technology. i have several sets that have been recharged hundreds of times with no degradation or damage.
i am more concerned about a battery short when the battery is NOT plugged into the vape. i'm about ready to drop the dime on a MakerBot so i can custom fabricate a battery case that will prevent the ends of the battery being accessible. Currently i'm using DipIt, a plastic coating material. And the Deans plugs i use have recessed contacts.
my design goal is to be as safe as a kitchen toaster. you can get pretty messed up by one of those, too.
There should be a warning sticker ... For sure, don't vape while in the hot tub.
Also, the stainless steel is wrapped with ceramic tape -- good for way over 1000F.
The spec sheet for the A123Systems batteries claims 120A max current for 15 seconds, 70A continuous ... when i have shorted the batteries (accidently) it is like putting a screw driver across the 120 AC line (which i've also done accidently) >>> sparks and etched metal.
The manufacturer does say the batteries don't explode or burn, due to the nanophosphate construction technology. i have several sets that have been recharged hundreds of times with no degradation or damage.
i am more concerned about a battery short when the battery is NOT plugged into the vape. i'm about ready to drop the dime on a MakerBot so i can custom fabricate a battery case that will prevent the ends of the battery being accessible. Currently i'm using DipIt, a plastic coating material. And the Deans plugs i use have recessed contacts.
my design goal is to be as safe as a kitchen toaster. you can get pretty messed up by one of those, too.
There should be a warning sticker ... For sure, don't vape while in the hot tub.
andrewburgess
Well-Known Member
Fuses handle all kinds of volts/amps; I don't think duty cycle frequency enters into it. If you plug it into a car, that plug is fused so that would protect you in that case.Hippie Dickie said:
ouch
That's not short circuit current. That's a do not exceed spec. Then again, the batteries are only a few thousand mA-hr so maybe there isn't enough energy to be dangerous. I wouldn't worry about the battery short scenario. But a stoner suddenly holding a 1000 degree metal cylinder? Ouch
That doesn't sound so bad.
That does put things into perspective
that's kinda been my theory ... i think once i get some beta units in the field i'll see some failure modes i never could have guessed.
Bubar
Well-Known Member
Shorting is a problem I've had in the past. Way back is a pic of a melted oven chamber. The short was glowing red. That is the main problem with the vape. I have been trying to get one ready for my non-technical minded brother, but I'm concerned shipping or something will jostle things too much, cause a short, and burn down his house. Lol. Although, since my casing is see through I can see the short. In the bud toaster, you wouldn't notice as easily.
Bubar
Well-Known Member
Maker bots are sweet. I'm waiting for kits to come out for the RepRap MKII Mendel to come out. they plan on having circuit printing abilities. Print a vape!!! (oh. after reading looks like they still haven't made promising progress) Though the mendel version is more accurate and has a larger printing area than the makerbots.
Bubar - did you ever diagnose where the short was happening? it would seem to me to be very specific to the physical layout.
i would think if the MOSFET shorted out it would just burn through the source lead on the MOSFET pretty quickly.
i would think if the MOSFET shorted out it would just burn through the source lead on the MOSFET pretty quickly.
Bubar
Well-Known Member
I think my gate line got melted through. I really don't remember. That particular model has had the controls ripped out. It also could have been with the old shitty mosfet. I used to have those mosfets blow up and short. Before I send the prototype (so busy with other shit won't happen for a while) to my bro, I'm gonna drop it, shake it, throw it, lol attempt to stress test the little fucker. I remember when I was in high school I forgot my Vapolution was in the trunk and went drifting... Never worked the same again... ahaha.
yeah, well, i'm kinda prissy about my tools, so i definitely don't abuse the Bud Toaster -- i treat her like the Lady she is.
i think the surface mount components would avoid any physical damage to cause a short ... but if the PIC aborts, who knows?
that's what beta testing is for ... i'm doing my part - all day, every day, but it definitely needs a non-HippieDickie tester.
i think the surface mount components would avoid any physical damage to cause a short ... but if the PIC aborts, who knows?
that's what beta testing is for ... i'm doing my part - all day, every day, but it definitely needs a non-HippieDickie tester.
andrewburgess
Well-Known Member
I was imagining a source-drain short in which case the nichrome would still limit the current so I don't think the mosfet would burn. Its technically still operating within thermal specHippie Dickie said:
. But how hot will the chamber get with the heater on essentially 100% duty cycle?
too hot ... could be BIC hot, say 1000F ... hmmmm, let's see:
Theoreticals:
battery pack (6.6v) / coil resistance (0.5 ohms) = maximum current draw (13.2 amps)
(batteries can safely sustain a 70amp current flow)
From the chart, 13.11 amps into 16 awg Nichrome60 produces 1000F
(straight wire in free air, coil runs hotter for same current)
2.3 Ah x 6.6 v = 15.18 watts, battery capacity
13.2 A x 6.6v = 87.12 watts, coil drain
15.18 / 87.12 * 60 minutes = 10.45 minutes = 627 seconds
Measurements:
Temperature rise at maximum dutycycle is 15F per second
Worst case:
15F / second * 627 seconds = 9,405F
Conclusion:
Coil would be glowing red hot ... initially just like the red LED, but then later maybe with more orange (?)
Instructions to user: Do not operate unattended!
Theoreticals:
battery pack (6.6v) / coil resistance (0.5 ohms) = maximum current draw (13.2 amps)
(batteries can safely sustain a 70amp current flow)
From the chart, 13.11 amps into 16 awg Nichrome60 produces 1000F
(straight wire in free air, coil runs hotter for same current)
2.3 Ah x 6.6 v = 15.18 watts, battery capacity
13.2 A x 6.6v = 87.12 watts, coil drain
15.18 / 87.12 * 60 minutes = 10.45 minutes = 627 seconds
Measurements:
Temperature rise at maximum dutycycle is 15F per second
Worst case:
15F / second * 627 seconds = 9,405F
Conclusion:
Coil would be glowing red hot ... initially just like the red LED, but then later maybe with more orange (?)
Instructions to user: Do not operate unattended!