Adventures in home reflow - toaster oven conversion

[bit.cyber]

Interesting. If I remember correctly from looking at the code some time ago it makes 5 samplings per second and averages the temperature. I'm surprised it fluctuates that much. You probably pick up some noise from the surrounding wires. Did you install thermocouple wire in parallel to power wires?

Yes - that's what it would seem, but I tried to avoid this as much as possible. There are a couple of photos in the earlier posts which attempt to show this.
Over the Easter weekend I'm going to pull it apart, again, to, at the very least, take some decent photos of the wiring. Maybe I'll find something in the process.

Making a presumption without evidence is not good, but I can think that the noise is being generated from the +5 V SMPS. Other than this, I'm none the wiser.

[ballanux]

Yes - that's what it would seem, but I tried to avoid this as much as possible. There are a couple of photos in the earlier posts which attempt to show this.
Over the Easter weekend I'm going to pull it apart, again, to, at the very least, take some decent photos of the wiring. Maybe I'll find something in the process.

Making a presumption without evidence is not good, but I can think that the noise is being generated from the +5 V SMPS. Other than this, I'm none the wiser.

Are you sure you actually have noise in the measurement? The temperature reading seems pretty clean to me, and about the "delta" measurement, it doesn't seem too noisy for a differential measurement, a derivative function will be always noisier. Also, the MAX IC has a resolution of 0.25ºC so you are going to see a minimum increment of that value.

I'm attaching my last profile test, you can see similar noise levels. On the cooling stage I have big temperature changes, but this is due to the addition of a couple of fans, I still have to tune their PID, but I like how they make the cooling profile much steeper than passive cooling.

[nickds1]

I'm honoured! I designed those boards years ago!

Nice project, BTW. Very interesting.

[bit.cyber]

Hi Nick,
Your power supply indeed works perfectly. I've incorporated into another design that I'm working on currently.
I'll likely post the results on one of the forums, but I'll also try and email you separately, per the email address on your website. Is it still current?

Colin