I purchased this new version of the PZEM-004T, but I can’t get it to work with WEMOS D1 in any way, I can’t tell if the piece is broken. Someone who has been able to use it, could kindly help me to understand where the problem is.
Thank you so much .
As the PZEM-004T expects 5V serial data and the WEMOS D1 mini only provides up to 3V3 the expected optocoupler input power of the PZEM-004T has to be reduced. This can be accomplished by soldering a 1k resistor between the joints shown below.
for that part v1 is like v3
Connect the serial interface of the WEMOS D1 mini with the serial interface of the PZEM-004T.
Still some hope exists, as it might be the serial bridge is faulty or wrong connected. Generally speaking I still own three of these boards and decided NOT to use them. I don’t like its design and found those (below) cheap (relatively) ready meters a better choice for three phase solutions.
Using the WEMOS D1 Mini PRO, connecting: D7 + TX PZEM, D8 + RX PZEM. These are the links I make but nothing works, I don’t see anything in the serial window.
Well, this won’t work!
The D1 Mini/pro has one and a half UARTS.
UART0 is connected to he USB socket and also to pins Tx and Rx. And is used for programming the device.
UART1 is Tx only and is connected to pin D4.
If you need to have Tx/Rx communications with a peripheral such as the PZEM then you’ll need to use UART0. If you also want to use a serial monitor to see debug output then you could connect an FTDI to D4.