μReflow Oven with MicroPython & LittlevGL

中文版请见于此。

This project is modifided and rewritten on top of Adafruit EZ Make Oven. The original code of EZ Make Oven can be found here.

The purpose is to make a reflow soldering oven by modifying a kitchen oven with more affordable and widely available hardwares.

The GUI of this project is built with LittlevGL (lv_binding_micropython) which is a very powerful and easy to use GUI library. LittlevGL already comes with drivers for ILI9341 TFT display and XPT2046 touch controller, this project takes the advantage of both to ease the user operation.

Bill of Materials

• 1 x regular kitchen oven with 10-12L capacity. Like this.
• 1 x solid state relay rated 10A. Like this.
• 1 x passive piezo buzzer. Like this.
• 1 x ILI9341 TFT display with on-board XPT2046 touch controller. Like this.
• 1 x MAX31855 thermocouple amplifier with K-thermocouple. Like this.
• 1 x AC-DC5v power supply to power the ESP32 dev board. Like this.
• 1 x ESP32 dev board. Like this.

Oven Modification and Wiring

• WARNING: The mains (220/110V) can be deadly. Make sure the oven is unplugged from the wall plug before doing any modification or wiring.
• Ovens are different one from another, but basically all you need to do is to bypass the original switch and timer, and let the solid state relay control the heating element, hence the ESP32 board can turn the heating element on and off via the solid state relay.

The Firmware for ESP32

• Pls refer to here.

Installation

• All files are under MAIN folder.
• After flashing the firmware, you need to edit config.json to change the GPIO pin numbers according to how you wiring your TFT display and other components.
• Make sure "has_calibrated": should be false
• Transfer all the files and folder under MAIN to the ESP32 dev board and you are good to go.

Usage Guide

• Upon powering on the first time, you will be guided through touch screen calibration and temperature calibration, throughout which the ESP32 board will reboot a couple of times. Just follow the guide.
• After calibration and reboot, the GUI will load, where you can select Solder Paste type from the drop-down menu, just choose the type you'll use, and the reflow temperature profile will show down below.
• If your solder paste isn't there in the menu, you can build your own solder profile files. Pls refer to: https://learn.adafruit.com/ez-make-oven?view=all#the-toaster-oven, under chapter "Solder Paste Profiles". The new solder profile json file should be put under folder profiles.
• All set and click "Start" button to start the reflow soldering procress.
• If you wish to re-calibrate either the temperature curve or touch screen, click the 'Calibration' button on the screen, and choose from the popup window. And follow the on-screen instruction.