How to solve Raspberry Pi 3B & Bme280 Remote I/O error - python-3.x

Let me start off with the components used:
GPIO extension board to connect the raspberry pi to components
Bme280
Pi 3B
Problem description:
This problem was intermittent at first. We were receiving reading and the error occured out of nowhere, made adjustment to the sensor(taking out and putting it back in) which solved it but when we touch the sensor the error showed up again.
We decided to change the sensor and the problem turned from intermittent to persistent. Now we have this as permanent issue.
We removed the package for BME280 and SmBus2 and decided to reinstall it again.
RPI Bme280: https://pypi.org/project/RPi.bme280/
I followed this BME280 installation guide, however when prompting for 'i2cdetect -y 1' there were lines but no number showing up.
What has been confirmed so far:
Patching up of circuits was fine, tested with my lecturer pi and it
works fine.
Codes is fine, we even use the sample code provided by RPi.bme280
I2c was enabled everytime
Please help me because I am really lost. I needa submit this by next week so any help is appreciated.
Problem pic --> Picture of the problem

I've tried to respond, but there is a few pitfalls in SMBus and i2c, so to break the question into smaller bits I've quoted your original message with an indent. The response is provided beneath.
This problem was intermittent at first. We were receiving reading and the error occurred out of nowhere, made adjustment to the sensor(taking out and putting it back in) which solved it but when we touch the sensor the error showed up again.
I locked onto the statement, "Touched the sensor". Is there a chance the BME280 experienced an ESD discharge? And therefore is now partially or fully broken?
Are you using an ESD safe room? or at least ESD bracelet. You will not notice small ESD discharges, and for small electronics even a sub 1000V discharge can cause damage instantly or over time. (Fundamentals of Electrostatic Discarge - incompliancemag.com)
I followed this BME280 installation guide, however when prompting for 'i2cdetect -y 1' there were lines but no number showing up.
The I2Cdetect -y 1
Will send a ReadBit message to each possible slave 0-127. Then listens for the ACK on the slave address.
The message is very simple, but does the trick for detecting working i2c slaves.
As you stated there is no "Lines", i would suggest the slave either has issues responding, if the BME280 has the correct 3v3+GND supplied.
As another possability, could you redo this step dtparam=i2c_arm=on,i2c_baudrate=400000
(Set the baudrate way down to 10000 /10k. Should this solve the issue and you need higher bandwidth, attempt on "50000 /50k" or "100000 /100k") This is just to eliminate the possibility the slave cannot opperate on this high frequency. 400k Baudrate for SMBus is high for a prototype/testing scenario. Very small amounts of interference can corrupt the data over SDA.
Another possibility is the Sink-Current which i've learned the hard way is not the same on i2c and SMBus over i2c.
Is you Pull-up resistor appropriate for the limited sink-current?
The SMBus specifies a minimum sink current of 100µA, and a maximum of 350µA, compared to 3mA for the I²C bus (Ampere=Voltage/Resistance Ohm).
Now to the Software issue.
From your supplied picture on imgur.
File "newcodes_''''''''''''''.py" line 2, in
Your compiler cannot find "bme" where you attempt to import bme280. Reference/path issue?
This can be the cause for other issues further into the code calls.
I don't know what SW you are writing the code in, but if there is an option to insert a breakpoint and run a debug build. I would suggest starting there :)

Alright I have resolved the issue, I changed the wire from jumper wire to hard wire. Thank you guys for your response. I appreciate all of them :D

Related

Linux: writing to the i2c/SMBus

I have a problem with the i2c/SMBus on a Linux System with an Intel Apollo Lake processor. I am trying to read/write from/to an EEPROM but I face some issues. My EEPROM is located at the address 0x56, and I am able to watch the Bus with my Logic Analyzer.
When I try to read from the device via i2ctools (i2cget) the System behaves as expected. My issue occurs when I try to perform a write command via i2cset for example. i2cset ends with an error (Write failed). Because I am able to watch the Bus electrically I can also say that all lines stay HIGH and the Bus is not touched. I was able to activate the dev_dbg() functions in the i2c driver i2c_i801 and when I perform i2cset I am able to find (dmesg) the debug message:
[ 765.095591] [2753] i2c_i801:i801_check_post:433: i801_smbus 0000:00:1f.1: No response
When running my minimal I²C Python code using the smbus2 lib, I get the following error message and the above mentioned debug message:
from smbus2 import SMBus
bus = SMBus(0)
b = bus.read_byte_data(86,10) #<- This is performed
b = bus.write_byte_data(86,10,12) #<- This is not performed
bus.close()
Error:
File "usr/local/lib/python3.8/dist-packagers/smbus2-0.4.0-py3.8.egg/smbus/smbus2.py", line 455, in write_byte_data
ioctl(self.fd, I2C_SMBUS, msg)
OSERROR: [Errno 6] No such device or adress
A big hint for me is that I am not able to perform a write command in the address space form 0x50 to 0x57. My guess is that some driver locks the address space to prevent write command to that "dangerous" area.
My question is: "Does anyone know this kind of behavior and is there a solution so that I can write to my EEPROM at address 0x56? OR Is there a lock surrounding the i2c adress space from 0x50 to 0x57 and who is my opponent?"
I am kind of a newbie to the whole driver and kernel world so please be kind and it is quite possible that I made a beginner mistake.
I would appreciate hints and tips I can look after surrounding my problem.
It seems that I found the cause of my problem. In this Forum post is described that Intel changed a configuration Bit at the SMBus controller.
OK, I know what's going on.
Starting with the 8-Series/C220 chipsets, Intel introduced a new
configuration bit for the SMBus controller in register HOSTC (PCI
D31:F3 Address Offset 40h):
Bit 4 SPD Write Disable - R/WO.
0 = SPD write enabled.
1 = SPD write disabled. Writes to SMBus addresses 50h - 57h are
disabled.
This badly documented change in the configuration explains the issues.
One Challenge is, that to apply and enable changes to the SPD-write Bit the System needs to be rebooted. Unfortunately while rebooting the BIOS will change the Bit back to the default. The only solution seems to be an adaption in the BIOS.
For me, this issue is resolved. I just wanted to share this information in case someone faces the same issues.

Not seeing anything in arduino serial monitor when typing the AT Commands for Bluetooth HC-05

I am a beginner to arduino and trying to follow one of the videos from youtube to make a project- Master And Slave using HC-05 modules. I followed every step from that video carefully. Here's the link to the video ->
https://www.youtube.com/watch?v=BXXAcFOTnBo
For Slave Module when I type AT commands in the serial monitor nothing shows up.
I searched in Internet for the this problem and still didn't fix it. Here's What i have done:
tired restarting my pc
tried Changing arduino, At first i used arduino nano and then uno
I tried changing the baud rate to all other values and nothing happened
And there is no change in light blink, it stays on AT command mode until power is turned off and on again.
This is how is looks
Thank You For the Answer
Your problem is not actually related to arduino in any way. This tutorial is utilizing onboard USB->UART transceiver IC. So in theory you could even remove Atmel chip from the board. Its more like using module like this FT232 converter. Anyways sorry if I confused you but you can research the subject.
But anyways to the problem. Couple of questions:
Did you press reset button on module while powerin up the circuit?
Thats the way it enters to AT command mode
Did you try to reverse RX-TX lines, don't worry connecting these guys across eatch other doesn't harm your board.
(They are so often plugged in wrong..)
Did you make sure you have connected EN pin of module also. (To arduino 3.3V not 5V)
Did you triple check all connections
Try to upload simple Sketch like blinky to Arduino to make sure you are connected to USB-UART transeiver and you have correct drivers.
Make sure you upload empty sketch or remove the chip when you try to apply tutorial steps.
Change jumper wires. Sometimes cheap jumper wires are really bad quality.
I have been sometimes scratching head for long time because of broken jumper cable.
Please let me know if you have checked all of those so we can think for next step.

rfid-rc522 Tag is not read

I am using the instructions of https://pimylifeup.com/raspberry-pi-rfid-rc522/ to learn how to read my rfid-rc522.
I installed all the things needed, and cloned from git all the files. I connected accordingly and double checked the wire.
The code in Write.py is
#!/usr/bin/env python
import RPi.GPIO as GPIO
import SimpleMFRC522
reader = SimpleMFRC522.SimpleMFRC522()
try:
text = raw_input('New data:')
print("Now place your tag to write")
reader.write(text)
print("Written")
finally:
GPIO.cleanup()
When I run it- The result stops after "Now place your tag to write" and nothing happens when I place my tag. Any help please? What's wrong here? The module gives red light meaning it is connected. Is it really connected? How do I know? Please help.
Edit: My title and tags were wrong in this question due to already saved data. I edited. :)
It can be multiple reasons why your reader is not retrieving any data:
The RFID cards that you are providing to the reader are not supported by the ISO 14443: Mifare Classic, 4K. (Some DesFire, etc...) are the cards you want to try. Source: https://en.wikipedia.org/wiki/ISO/IEC_14443
The MFRC522 is not receiving enough input voltage. Try to increase from 3.3V to 4V. I have tried with 5V months and the reader is still running perfectly, but be cautious. The safe range in NXP is from 2.5V to 3.6V. Source: https://www.nxp.com/docs/en/data-sheet/MFRC522.pdf
The library you are using does not support IRQ (Interruption Request). This means the process of reading UIDs is high CPU consuming and low in performance. Try to use this popular library which supports interruptions: https://github.com/ondryaso/pi-rc522 . You will need to connect another wire from the IRQ pin in the MFRC522 to one GPIO pin in the Raspberry that is free and supports reading/writing operations.
Check if SPI interfaces are enable in Raspbian. Open a terminal and run:
ls -l /dev/spi
Lastly, it could be that your reader is broken. Some chinese versions do not work as they should do. Maybe you should buy another one and try more luck.
I suppose you have connected all cables in the correct way between the MFRC522 and the Raspberry Pi. Check that again.

Beaglebone Black Custom Audio Cape DMA/IRQ trouble

I'm running a BBB straight out of the box running debian. Kernel version is 3.8.13-bone-47.
I'm working with a cape that is very similar to the one here. The difference is that I'm using a TLV320AIC3106 instead of the AIC3104, and I only have enabled the audio out, I'm not interested in recording audio in this application.
My pinout for my application is identical to the cape in the link above.
I've followed the link here to get the cape up and running. Everything that I have matches the output of the tutorial up until I try and play a sample wave file.
When I play a sample wave file, I get the following message: aplay: pcm_write:1710: write error: Input/output error
Running dmesg gives me ALSA sound/core/pcm_lib.c:1010 playback write error (DMA or IRQ trouble?)
Where I'm having trouble is I don't understand how the DMA is coming in to play. Is this a DMA problem? Is it a symptom of something else going wrong like my I2C? Am I missing a configuration somewhere else?
Any thoughts on how to track this down are appreciated.
I realize it has been covered in multiple places before, but it can never be stressed enough. Make sure that when you're sending out information, make sure it goes to the right address over the I2C. I figured out this morning that the audio codec was at address 0x1B, while the driver was addressed to 0x18. Small but critical difference.
The easy fix is to edit the BB-BONE-AUDI-02-00A0.dts file.
Edit line 65 to <0x1B>. Re-compile using the line: dtc -O dtb -o BB-BONE-AUDI-02-00A0.dtbo -b 0 -# BB-BONE-AUDI-02-00A0.dts
move the generated file to the /lib/firmware directory
Insert it using echo BB-BONE-AUDI-02 > /sys/devices/bone_capemgr*/slots
After applying this simple fix it seems to work. I can't say for certain because I have to get the audio amplifier circuit up and running still. At least aplay will play the file without crashing out on me, which is a start.

RN-41 bluetooth and dsPIC

Having a couple of issues with what I was hoping to be fairly straight forward.
I've been transmitting data from my PIC to a PC via RS232 at a baudrate of 115200. I've recently got a RN-41 bluetooth module and was hoping the switch would be as simple as powering the module and connecting the PIC TX (via a max3232) to the RN-41's RX, as the online community has led me to believe.
I'm able to connect to it and pair it to the computer, I'm also able to use PUTTY/Realterm to change the parameters, like the name and baudrate. Finally, by connecting a link to the RX and TX on the bluetooth module and powering it, I'm able to ping text by sending and echoing it using PUTTY, so I'm fairly sure the module isn't broken.
However, when I try to transmit my data from the PIC to the bluetooth module, and view it using realterm (which was working fine with the wired connection) I'm getting data received, but it's not what is expected. I'm expecting a packet of 25 bytes, with a header value of 2, I'm getting around 12-15 bytes and a header of -65.
The first value, -65, is always the same, and the other data can change, which really suggests a baudrate problem, but I've tried a variety of baudrates (changed in my UART code, the bluetooth parameters, and in realterm), and the data doesn't change at all; always wrong.
What have I missed? Anything I need to change in the Bluetooth configurations? I've also checked the parity bit, stop bit, etc, all the same as each other.
The problem was the MAX3232 circuitry. It was necessary for the RS232 connection I was using prior, but when I wanted Bluetooth, which required TTL signals, I was feeding it the same RS232 data!
Making a link straight from the PIC to the Bluetooth receiver solved this problem. Hope this helps someone else in the future!

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