T12 soldering iron + 858D hot air gun two-in-one rework station_low voltage part

My product is divided into two boards: high voltage and low voltage. This link is the low voltage part. The high voltage part is as follows: https://oshwhub.com/red_bean/T12lao-tie-858Dre-feng-qiang-er-Hig Original reference address: https ://www.hackster.io/sfrwmaker/stm32-based-soldering-and-rework-station-e3955b My note: Updated on 2020/4/16: Updated the R1 R2 resistors. The original resistors match the hardware I am currently using. A little bit different. 1. Originally, I made a board for integrating high and low voltage and tested it and it works; 2. Later I separated high and low voltage. Now I will release the low voltage part first. The high voltage part is still under testing. I will release a project after the test is completed. And will post a link; 3. The original author provides OLED12C and ips screen options. In the current schematic diagram, I only use IPS wiring, and there is no 12C interface reserved; 4. There are two main switch parts on the front panel, the main It involves a 220 for the main switch and a 3-6V for the air gun switch; 5. In terms of wiring, XH2.54 is used for signal and low voltage, and VH-2P is used for high voltage control, which effectively ensures the safety of electrical appliances; 6. In terms of input, I did not use the solution provided by the original author. The bottom board uses a T12 soldering station power board, using 30MM long copper pillars for connection, and leaving about 5MM of space; 7. In the 5V transfer part I used the XL_2596_5V solution, and then isolated it through the isolation circuit of B0505S_1WR2, and it can be used after testing; 8. I reserved two signal interfaces on the P3 port on the motherboard, which can be used to add temperature-controlled fans later; this project has The following features: The controller allows simultaneous use of a hot air handle or soldering iron. The reed switch on the handle of the Hakko858D hot air handle is used to activate the rework function. The soldering iron can be automatically turned off or allowed to continue working according to the configuration parameters in the main menu.

• Optional hardware switch to completely disable the hot air handle and disconnect it from the controller.
• The hot air handle is powered by the full sinusoidal half-cycle voltage peak and does not interfere with AC outlets.
• This controller supports a single OLED display based on the SD1306 chip using a 7-pin SPI or I2C interface. No additional recompilation or code modifications are required. If an OLED display is found on the I2C bus during startup, it will be used, otherwise the controller will initialize the display on the SPI bus.
• The controller checks that the tip is connected by testing a small amount of current flowing through the tip. If the nib is not connected to the iron handle, an error message will appear on the home screen. This feature allows quick tip replacement in standby mode. When the soldering iron is powered off and the tip is removed from the handle, the "Replace Tip" procedure is initiated.
• Before powering on the hot air handle heater, the controller checks whether the hot air handle is connected and its fan is working properly. This increases the security of the controller.
• The controller will keep the hot air handle fan working at low power until it gets cold. When the power is turned off, the fan speed of the hot air handle will be automatically managed.
• The controller uses ambient temperature (sensor inside the FX9501 handle or in the case of the controller) to correct the tip temperature measured by the thermocouple.
• The controller supports individual calibration of the tip via four reference points at 200, 260, 330 and 400 degrees Celsius.
• The controller supports calibration of the hot air handle through four reference points of 200, 300, 400 and 500 degrees Celsius.
• A dedicated calibration procedure is implemented in the controller to simplify the calibration process of the nozzle or hot air handle.
• The controller uses a 50 HZ PWM signal to control the power provided to the welding tip. This keeps the controller silent.
• A PID algorithm is used to manage the power provided to the soldering iron or hot air handle. This keeps the preset temperature very accurate.
• An accelerated rotary encoder algorithm is implemented in the controller, allowing changes to be made quickly.
• Temperature can be displayed in two degrees Celsius: Celsius or Fahrenheit.
• If inactive, the controller will perform an automatic shutdown procedure.
• Implement standby (low power) mode using the optional hardware tilt switch.
• The U8g2 graphics library is implemented in the controller.
• To prevent the OLED display from degrading, a screensaver mode has been implemented.

Appreciation of finished product pictures: production process and test pictures: