ESP8266 with Hi-Link

I have built a few esphome devices using ESP8266 modules and every time I’m struggling to find a reliable power supply for the ESP8266 and mount everything in a box with hot glue. I always end up with cables for power lines and sensor signals getting tangled up.

I decided to build a single pcb for both the AC power supply and the ESP8266. The Hi-Link isolated switching power supply module has become very popular and I have seen many makers using it with D1 mini or other similar boards. I designed my board for a HLK-PM03 which is the 3.3V version of the Hi-Link. I have included some extra components before the Hi-Link input for safety. There is a 0.2A fuse, a MOV and a thermal fuse.

My first utilization of this pcb is an esphome energy monitor with PZEM-004T V3. Both boards fit in a rail box and it monitors the entire house’s energy consumption.

If you want to experiment with it you could find a bare board in my store and build one yourself.

My pcb could be used with a ESP12 module or a D1 mini module. Here you can see the schematic. In case of D1 mini, you cannot solder the 5V line, since it was designed for a 3.3V power supply.

Danger – High Voltage! Use it at your own risk!