I’ve been having trouble with my composites oven. I think it lies in two areas:

1. it’s a little leaky – can be fixed with a bit of expanding foam and a more careful cut of the kingspan i’ve used to make it. I could build a wooden frame for it as well, but that seems a lot of faff
2. The sestos PID controller I have is a bit hard to use – it’s well understood the chinglish instructions are abominable.

So, how to fettle this myself?

I’ve found this great page at mbed.org which gives a great description of what the variables mean and how to set up a PID. Now at least I am armed with the info I need to fix this.

I’m actually thinking of making my own and the plan is:

• keep the triad switch for the oven, fan, etc.
• write a C++ application to do the PID control from a PC
• configure multiple ramping profiles that are saved and can be selected at will
• the application can have multiple learning points, so the PID can be most efficient at each ramping step
• use a pair of xbees to provide wireless sensing and control of the oven
• have 3 temperature sensors – two in the oven and one for ambient temperature
• have a set of fans in the oven as well as the initial fan so that hot-spots can be eliminated
• logging so you can see what the temp was doing

Saying that, there’s also this quite sophisticated controller which does most of the above and has a serial interface and instructions in English. So, I could write the application to control the PID and just use it for logging – but I wouldn’t get the wireless control of the oven (mine is in the shed).

Your thoughts?

Choices, choices.