Being a software guy I've often promised myself that I would never build one of these toaster based reflow ovens. But playing with Moteino's for a couple of months I've often run into the resulting limitations. So I needed to do something.
There are a lot of projects on the net showing how to build these reflow ovens. Just about all of them have a big issue that seems to be lost on the authors: They all involve creating custom PCB's for an oven controller using a microcontroller, a thermocouple and solid state relays. Well that's all very nice, thank you, but I need a reflow oven to create custom PCB's in the first place.
So without further ado meet Moteino-Reflow, my super simple solderless reflow controller. It's just a Moteino connected with jumper cables to a MAX6675 based thermocouple and a regular RF AC-socket. I've previously posted some code to enable Moteino's to control these sockets using the RFM69 module.
Couldn't be more simple and works perfectly (in theory, actually soldering is next). The resulting temperature profile looks pretty good:
I started out with the PID library and a mixed duty cycle to control the temperature. Works well and I can have the moteino set any temperature and hold it within 1-2 degrees. But in the end I found it's best to just heat full power until 110 celsius, wait until the temperature overshoots to over 150, wait another 25 seconds and then heat full power until 205 degrees. Open the door at 220. This is all not based on actual soldering, but trying to replicate the kester profile.
I hope it will work in practice as well.
Joe
