For Christmas, [Hamster]’s wife gave him a mini-oven. later that day, he tore it apart and built this FPGA controlled reflow oven.
We’ve seen plenty of reflow oven builds in the past. many of those projects use a microcontroller to do closed loop control, sensing the temperature and toggling the heating element to hit a set point. This build uses the Papilo One FPGA development board as a controller. It implements a state device that meets the reflow profile of the solder paste, ensuring SMD components are soldered properly.
The oven uses a MAX31855 to read temperature from a thermocouple. This device offers amplification, cold junction compensation, and analog to digital conversion which spits out the temperature over SPI. To control the heater, a 40A solid state relay is used.
The VHDL code that drives this oven is linked in the writeup, and has some interesting bits for those wanting to try out FPGAs. It includes an SPI interface, display driver, and the temperature state device logic.
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