Yep, it's my turn to have a go at partially automating my meat smoking process. After reading through Brent's thread and seeing folks on a smoker thread posting about a controller, it was time to see how I could do with it. My parts list is much the same as Brent's; the main difference being the addition of two indicator lamps - one for power on; the other for relay on. When I was ready to order, Amazon listed a 'kit' that included the MyPin TD4 PID, SSR-25A relay and a heat sink for about $38. The type K probe was about $5. I spent about $20 at Radio Shack for connectors and a switch. Add some scrap wood and you got it.
As I started getting parts together, I connected various items in turn to test as I went along. I began to get a bit of a rat's nest.
The "blower" is almost cute! All one needs for my application is 4-5cfm. This little guy puts out 4.2cfm. It will be used in place of the damper on the side firebox. Any more air flow than this would blow ashes into the cooking chamber.
The project did include a bit of woodworking. Nothing fancy, though - serviceable is enough!
Time to break everything down and mount it in the boxes. From left to right: blower, main switch, PID, SSR/Heat sink, power outlet for the 12v power supply to feed the blower.
It fits with a little room for wiring!
Even the little guy has a home now.
And - it works again! A note here: After doing this assembly, I tested the probe/PID in the kitchen. In boiling water, the probe read 212°F on average, varying a degree or two depending on where it was in the water. In a glass of ice water, it showed a temp of 36°F.
I mounted the probe in the back center of my smoker at cooking grate level.
Now, some techy stuff. One of the things I've heard universally is the lack of documentation on the operation of the MyPin T series PIDs. I took Brent's setup and numbers as a starting place, but kept playing around with different settings. I also did a bit of research just to get a handle on PID terminology, which also helped. One thing I did NOT like about the way the PID was controlling the SSR is the switching on and off when the probe temperature was near the desired temperature. I kinda figured the hysteresis settings should have some control over the range of temperature in which the SSR would be switched; however, no matter how I set any of the hysteresis points, nothing changed. After I had read the instruction sheet for the umpteenth time, I finally saw the phrase, "Not available when P is not OFF". So, I went through the setups, switched P(Proportional band) OFF. Now, the Control Hysteresis is in play, meaning I can set the hysteresis at 10, my desired probe temperature at 225°F and the blower will turn off at 225°F and back on at 215°F. Stating it otherwise, whatever probe temperature I set, the PID will control the system over a +/-5° range (220-5=215, 220+5=225).
So, here are my settings:
P = OFF
I = 132 (Brent's number)
d = 36 (Brent's number)
HYS = 10 (or whatever range you need)
My next step is to start preparing the beef brisket, beef ribs and pork spare ribs I bought to cook Saturday!!!