Main Content

So here’s the “PCB Hotplate slightly bigger edition” which is Version 2 of my previously made PCB Hotplate project.

The most significant change in this project was the size of the hotplate, which is approximately 99mm x 98mm in total and the heating area, which is approximately 65mm x 98mm. (The previous hotplate was tiny, measuring only 60mm x 90mm in total, with a heating area of only 60mm x 55mm.)

The new model is powered by an XIAO M0 DEV Board and features an OLED display that shows the current temperature of the heating coil.

XIAO was chosen due to its small size and the ATSAMD21G18 microcontroller, which is an ARM Cortex-M0+ processor. Seeed Studio created it, and it is part of the Seeeduino XIAO family.

The board is small, measuring only 20.3mm x 17.8mm, but it is powerful, with a 32-bit, 48MHz ARM Cortex-M0+ processor, 256KB flash memory, 32KB SRAM, and a variety of communication interfaces such as I2C, SPI, UART, and USB.

Like the previous project, this version has a coil setup that is driven by a Mosfet IC that cuts off the power when a certain temperature is reached, then reconnects the power when the temperature drops, which is currently set around 210°C as declared by the code below.

This hotplate is powered by a 12V 4A source; if we use a 12V 10A SMPS, the temperature will rise faster and reach 210°C+; the current maximum temperature observed is 207°C.

I hate to say it, but the temperature reading of this hotplate still needs to be fine-tuned; the NTC was placed at one edge of the coil, and the temperature around that area and the temperature around the center of the coil are different, as evidenced by the two different readings in the attached image. An external temperature meter was temporarily added to determine the temperature difference between the center and edge of the PCB.

These were the materials used in this built-

- Custom PCB
- MPS2314 buck converter IC
- SSD1306 OLED Display
- DC Barrel jack
- ON OFF DIP Switch
- MPS2314
- 10K Resistor
- 10R Resistor
- 7.5K Resistor
- 75K Resistor
- 40K Resistor
- 100uf Capacitor
- 10uf Capacitor
- 1H inductor
- M7 Diode
- PCB Standoffs
- Female header pins
- 12V SMPS
- Solder paste
- Test PCB for reflow
- Patience”

Link to article