Hello! I've got an ACM26G RFID module (the optional version of it that has rs232 aswell as rs-485 and Wiegand) and I'm struggling to make it communicate with an arduino nano by using a MAX232 module to translate the rs-232 into TTL.
The reader by itself is fully functional. it powers on and puts out data when a card is held near it (tested with an oscilloscope), but the Arduino is unable to read any data off it
This is how it is all hooked up:
The TX of the MAX232 module's TTL side to pin 6 of the Arduino (pin 6 being the softwareSerial receive pin in my case)
the TX of the ACM26G to the RX of the RS232 side of the adapter (DB9 pin 2)
a common GND between the reader,adapter and arduino
The reader gets its power from a 12v lab power supply, the Arduino and MAX232 adapter gets its power from the USB 5V line
I've attached the pdf of the reader module and my code . I also have to note that the RS232 side of the adapter is in DB9 format and the pins other than RX and GND aren't hooked up to anything
I've never before worked with the RS232 protocol so there might be an easy fix that I just don't understand
The code has been formerly tested with the RDM6300 module
I have also attempted to hook the rfid reader up with an RS-485 to TTL adapter but I've had no luck with that either
Edit: Attached photos of the wiring setup, accurate color-code
The pictures on ebay don't show it. Is the DB-9 of the RS-232 module a female connector? If yes, pin 2 is TX no RX. Pin 3 is RX. That may explain your problems.
Update: After wiring it up correctly and getting a card close to the reader a few times, the chip on the RS232-TTL adapter got really hot for some reason (and is probably fried) while the Arduino has still failed to receive any data (the led on the adapter was turning off while the reader was sending out data)
Could it be a communication level issue?
maybe the data transmitted by the reader peaks at 12v (which I have just assumed it does not while not being specified by the manufacturer). Going to try it through a voltage divider to see if it works at 5v, if the adapter hopefully isn't fried
Doesn't the NANO have a 3.3 volt input restriction? If I understand correctly the MAX232 outputs TTL level signals. I'm pretty sure that's not going to be good for the NANO's input.
I have had good results with SEEED Studio's RDM 630 RFID reader (125KHZ). It outputs serial data, so you don't need anything to convert it. A simple 3 resistor divider can be used to lower this to a level suitable for the NANO's input. With a larger antenna I've even managed to get a 3 to 4" range.
I'm currently using the RDM630 with a NANO 33 IOT to operate an RFID tag controlled pet door...
Doesn't the NANO have a 3.3 volt input restriction?
A standard Nano runs on 5V. If OT is using one of the newer boards (unfortunately Arduino named them stupidly also Nano) with some naming addition (BLE, IOT, etc.), it should be clearly defined.
Update: After wiring it up correctly and getting a card close to the reader a few times, the chip on the RS232-TTL adapter got really hot for some reason (and is probably fried) while the Arduino has still failed to receive any data (the led on the adapter was turning off while the reader was sending out data)
Post schematics of the RS-232 board. If the vendor doesn't supply it, reverse engineer it using the beep feature of a common multimeter.
