Electrification
After the first tests with the SoftPWM on a breadboard, I now soldered everything together and pressed it into an old PSU case of an old PC. Actually this is a prototyping case, but I know how long those things are lasting usually. I guess, if it works, I will just improve it slightly, but leave it ;)
Technically it looks pretty good. As you can see in the video, I can set a temperature, which my simple regulation in CODESYS tries to hold. I published the data and the control element in a web visualization, so that I can control the smoker from my smartphone.
I tried to keep the regulation circuit as slow as possible. But I defined myself a tolerance which the circuit should compensate in a given time. The regulation should react on a deviation of 5 degrees after 10 seconds. But currently this is just a mind game, and I will for sure know more after the next weekend ;)
After the test...
Sadly the temperature sensor didn't work relyably. Furthermore I had the known issue with the air, which is sucked through the gaps of the lid.
So my todos:
- fix the SPI driver
- fix the lid
The good thing:
The ribs have been the best which I have eaten since years. Really amazing.
So you see that the electrification is not mandatory, but convenient.
Last edit: Ingo 2018-08-26
Update
Neither the temperature sensor, nor the driver were the problem. Just the SPI speed was not correctly set in the SPI master. After limiting the speed below 25MHz, it works like a charm ;)
Last edit: codesys.com 2018-09-01
You probably mean 2.5 MHz?
No I meant 25, as I have read this somewhere. But practically I reduced it much more, as I don't need such a high speed, and I want to have it running stable.
Definatly a fun little project ;-)
Thumbs up!
This is a very interesting project!
Can you tell me how large your battery pack is and how long it lasts powering the fan and Raspberry Pi? Sometimes I smoke large cuts of meat such as brisket and pork shoulder that can take upwards of 14 hours total. Currently I adjust temperature the old fashioned way - by fiddling around with the vents and frowning while looking at the temperature. This gets old after 6 hours or so, no matter how much beer I drink
Sorry! Your mail was in my spam folder. Just found it ;)
I didn't run it such long, yet. But after 6h my 20000mAh Anker seemed to have max 1/3 of power lost. So feels like I could reach 18h w/ it.
But I guess, that a default Raspbian will also eat more. As then more services will run in the background.
I used wharfie, but you could also try to disable all unnecessary services in a Raspbian image.