I have a project going to use these little relay boards with the ESP-01 Wifi boards. I ordered 5 of them from a seller on Ebay and got them yesterday in the mail. Imagine my disappointment when I popped my already programmed ESP-01 in only to find that they don’t work at all.
The first thing that I noticed was that the CHPD and VCC pins weren’t tied together so that the board will go active. Thinking that might be the problem I soldered a jumper across the bottom pins. The board still wouldn’t go active after that, so I started to dig deeper into the problem.
A google search lead me to this video in Russian, which I don’t speak or read. I was fortunate enough to find someone that could translate it and give a synopsis. This morning I started working on one and after a little trial and error I finally got them working. After that it was just a matter of modifying the other four units.
Steps for Modifying
- First, re-flow all the solder on all the through board parts on the bottom. The soldering on these is complete crap and there’s lots of cold joints.
- Find the trace at GPIO0 and scrape away enough masking so that you can solder a jumper to it.
- Cut that trace as close to the masking on the GPIO0 side as you can. Cutting it there will make it harder for the solder to bridge on a later step.
- Solder a jumper from the CHPD to the VCC pins on the bottom side of the board.
- Solder a 3.3K resister from VCC to GPIO2 on the bottom.
- Solder a jumper from GPIO2 to the area that’s cleared of masking.
Checking your work
Make sure there’s no continuity between GPIO0 and GPIO2. If there is, check for a solder bridge where you cut the trace. Make sure there’s no continuity between GPIO2 and the 5V input or Ground since when scraping the mask off you could have exposed those areas and bridged when soldering.
Plug in your ESP-01 and give the board 5v and see if everything works. The video I found mentions changing out R1 on the top of the board, I didn’t find that to be necessary as it appears it doesn’t have any problem firing the relay.
You can see in the picture above I used all the lead of the 3.3K resistor as my jumpers between CHPD and VCC as well as connecting back to GPIO2. I then used another cut lead from something else as my jumper to cut trace.
Good luck, hope this helps someone else get these things working. It’s really quite sad that these are being sold by the thousands and they don’t work.