For another project, I needed relays to be able to switch a few pumps. During this, the ES32 boards caught my eye on AliExpress. These come completely ready to use and even have some with a 240V power supply on board.
ATTENTION: While the programming port on the boards is marked as 5V, the fact that my boards were only programmable once leads me to believe that the 5V is only the supply voltage and the data lines only operate at 3V. Fortunately, I flashed OTA on the first try. I will still check if I can replace the ESP on a board.
Facts
| Description | Board 1 Relay Programmer | 1 Relay + Power Supply | 4 Relays + Power Supply |
| DC supply voltage | 5V-60V | 5V-30V | |
| AC supply voltage | – | 90V-250V | 240V |
| Controller | ESP32-Wroom-32E | ESP32-Wroom-32E | ESP32-Wroom-32E |
| Switch | 1 | 1 | 4 |
| Relay coil voltage | 5V | 5V | 5V |
| Relay Contact Voltage Max | 30V DC 250V ac | 30V DC 250V ac | 30V DC 250V ac |
| Maximum relay current | 10A | 10A | 10A |
| Relay Contacts | NC/COM/NO* | NC/COM/NO* | NC/COM/NO* |
| USB Port | Micro USB | – | – |
| Size | 57.5mm x 53.7mm |
Normal Closed/ Supply Voltage/ Normal Open
| Description | 1 Rel. Board | 2 Rel. Board | 4 Rel. Board | 8 Rel. Board | |
| Relay 1 | 16 | ? | 32 | ? | |
| Relais 2 | – | ? | 33 | ? | |
| Relay 3 | – | – | 25 | ? | |
| Relay 4 | – | – | 26 | ? | |
| Relay 5 | – | – | – | ? | |
| Relay 6 | – | – | – | ? | |
| Relay 7 | – | – | – | ? | |
| Relay 8 | – | – | – | ? | |
| LED | 23 | 23 | 23 | 23 |
Areas of application
- Fundamentally, if other voltages need to be switched.
- Switch light scenes
- Pump control for irrigation
- Fan switches, e.g. for basement drying
- ...
Views
Programming
Libraries
Nothing special
Test programme
The PCB can be selected in the definition. The test program switches all relays on one after another and then switches them all off step by step.
Problems
Programming interface probably 3V.
Miscellaneous
—
Conclusion
I like that the ESP ports have been brought out, this makes it possible to connect further peripherals. Two of the three boards do not have an onboard programmer; while this can easily be remedied with an external programmer, it's still a hassle. The boards are very specialised, but for someone looking for a board with a mains voltage supply and who wants to switch a few things, the two boards with a voltage converter offer a complete package.
Related Posts
Sources
https://de.aliexpress.com/store/912246115?spm=a2g0o.detail.0.0.76fa7c1fXWn9rP
I have the two-relay and four-relay versions.
With the 4-relay board, some of the relays are unusable because outputs from the ADC2 are used, which do not function correctly when the Wi-Fi access point is activated. (The ESP32 problem is known but was not taken into account.)
The 220V power supply can barely handle any load and, although the low-voltage conductors are relatively well protected by slots, it's not very safe.
I often have problems with the One Wire bus on the 2-relay board, I don't know why yet. But here too, the voltage regulation is undersized. If I operate it with 24 volts and only use the relays on the board and a few digital inputs, the voltage regulator fails within a few weeks. I operate these 2 relay boards with an external 5-volt power supply, but they are not reliable even with this, they run for a few months and then fail. If I use a separate power supply, a separate ESP32 or 8622, and a relay board or an SSR board, these run for years without problems. Although I can't really see any real difference, I think that second-choice processors are used here, and everything is dimensioned at the limit.
Perhaps someone has had better experiences with it, I have/had 4 of each version in use, which I also purchased from different suppliers.