Timatgithub1
commented
2 years ago I have the same issue. Using this api with the SparkFun M6e Nano breakout board and a RPi 3b.
Error as shown below:
pi@raspberrypi:~/code/python/mercury-rfid $ python
Python 3.7.3 (default, Jan 22 2021, 20:04:44)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import mercury
>>> reader = mercury.Reader("tmr:///dev/ttyS0", baudrate=115200)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: Timeout
>>> System:
- Raspberry Pi 3B
- Sparkfun RFID reader, using M6 nano https://www.sparkfun.com/products/14066
- Debian buster based Raspberrian
- Python 3.7.3
- API installed by using: pip install python-mercuryapi -b $HOME/tmp
Checks:
- Board and api work, I have successfully scanned tags using an FTDI LC231X USB to serial adapter
- The Pi’s UART works, I have successfully communicated between the RPi and an Arduino using UART*
- I have changed the RPi config settings for enabling UART and disabling the Unix serial console as described here
- The Pi user is part of the dialout group
- As described in in this link, I have modified the TXB0104 by soldering a wire from the VCCB to OE in order to disable the 5V - 3.3V separation and use 3.3V. The new setup works, since I have successfully used it with the FTDI adapter in 3.3V mode (has an 3.3V / 5V jumper). But it dit not solve the timeout error.
By now I exhausted all options I can think of to solve this issue.
Some guesses:
- I am quite confident the hardware and the api part of the software work.
- I assume it must have something to do with the link between the library and the UART connection.
So I guess either an installation or configuration issue.
When I used the UART for communicating with the Arduino I used the Python Serial library, this may not be the same as what the gotthardp’s python-mercury api uses under the hood (I don’t know how this is addressed under the hood, since I have no experience in C). In other words, I tested the UART in a Python way, but this may not mean much in regards to the Python-mercury api.
Any suggestion will be much appreciated.
*UART between RPi and Arduino as described here Using this LLC Using the following code:
import time
import serial
ser = serial.Serial(
port='/dev/serial0',
baudrate = 9600,
parity=serial.PARITY_NONE,
stopbits=serial.STOPBITS_ONE,
bytesize=serial.EIGHTBITS,
timeout=1
)
while 1:
ser.write('Hello\n')
time.sleep(1)
TheAdoxBox
To start off, I do believe the issue is with the hardware, and not the software (as seen in other posts regarding the 'Timeout'). I have also confirmed that the Pi's UART (GPIO 14 and 15) are working (tested with an oscilloscope). I have been using the M6e Nano board from SparkFun (https://www.sparkfun.com/products/14066) as well as the Raspberry Pi Zero W. I have also been using an external antenna (which I confirmed has been setup correctly). I have the following setup (both supplied with sufficient power at 5V): Pi Reader Tx -> Rx Rx <- Tx Gnd <-> Gnd
The reader outputs 5V, but the Pi is not 5V tolerant. Therefore, I setup a voltage divider to step down the reader voltage from 5V to 3.3V for the Rx pin on the Pi. Everything seemed to work after confirming the voltages with a multimeter. Fast forward to the following day, the exact same setup is configured, but now, the 5V from the Tx on the reader dropped down to around 4V and the Rx on the Pi (after voltage divider), dropped down to around 2.11V. Nothing was changed from the previous setup (including the software), but the values changed somehow. The correct voltages are read if no connections are made between the two devices as well. I am led to believe that the logic level shifter needs a certain amount of current to be drawn to receive the desired voltages and that somehow, enough current is not being drawn by the Pi. I don't know how that would change when the setup is the same, but that is the only thing I can think of. We have done more testing, but this has been the most recent findings. Any help would greatly be appreciated.