9/8/2023 0 Comments Python serial![]() ![]() Serial communication is simple, but also complex and not easy. GitHub because documentation does not describe this possibility.There is this open issue Explicitly mention bytes and other buffers in the documentation for float() I tested that float() can convert directly from bytes, it treats the characters as ASCII and calling. Print(value) # do whatever with the value Value = float(record.rstrip(b'\r\n\x00')) # remove CR, LF and NUL at the end If not record or record != 0: # incomplete record read means timeout Record = ser.read_until(expected=b'\x00') # read null-terminated record Port='COM4', timeout=5 # set your parameters as needed, reading timeout 5 seconds Just add the serial port parameters ( baudrate etc.) as needed, adjust the timeout and you will probably want to collect the received values into a list ( your_list.append(value)). The following code should resolve the problem. PuTTY and other terminals do not show NUL characters. It looks like your device sends null-terminated records. This method can be used to take pressure measurements in the laboratory, or even record calibration data to improve your instrumentation accuracy the possibilities are truly endless.I think it is practically impossible that wrong parameter settings of the serial port would cause it to read extra NUL characters ( b'\x00', also called null character) and otherwise read correct data. I use pySerial often, whether for recording temperature data using thermocouples, or high-frequency hall sensor measurements to monitor moving parts. However, importing the data into Python frees the user of middle-men and allows the data to be processed in any way preferred. Often, with Arduino the user is trapped in the serial port, or is relegated to communication via protocols, which can take time and energy. With real-time datalogging via the serial port, one can mimic the laboratory setup of acquisition, analysis, and live observation. This method also allows the user to bridge the gap between live data and laboratory measurements. Printing data to Arduino's serial port and then reading it through Python gives the user the freedom to investigate the data further, and take advantage of the advanced processing tools of a computer, rather than a micro controller. I found Python's pySerial method a while ago, and I wanted to share its capabilities with makers and engineers that may be having the same issues that I was encountering. This tutorial was created to demonstrate that the Arduino is capable of acting as an independent data logger, separate from wireless methods and SD cards. The slow loop is a result of the plotting, so once you comment out all of the plot code, you will get a much higher data rate and. I actually used 0.8 seconds as the time between data records and it appeared to catch all data points. I found that my loop took roughly half a second to complete, which means that my serial port should not be outputting more than 2 points per second. This will prevent lost bytes and dropouts of data. Do some tests to verify the speed of your loop. I found that I was missing bytes or they were getting backed up in the queue in the buffer. Therefore, I advise anyone who is using the method below to assess whether you are reading all the bytes that are being outputted by the Arduino. ![]() I found that updating the plot occupied a lot of processing time, which resulted in slower reading of the serial port. NOTES: while I was using Raspberry Pi, I came across an issue between reading the serial port, saving to. ![]()
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