LoRa Radio No Connection

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bpjmalone
 
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LoRa Radio No Connection

Post by bpjmalone »

Hello, I am attempting this project with the LoRa Radio Bonnet for Raspberry Pi along with a Raspberry Pi 3B+: https://learn.adafruit.com/lora-and-lor ... i/overview. I believe that there is a hardware issue because the OLED does not do anything when running the test Python code listed in the project. I soldered wires on the Bonnet based on the diagram here: https://learn.adafruit.com/lora-and-lor ... -pi-wiring. E.g., SDA on Bonnet to SDA on Pi, SCL on Bonnet to SCL on Pi, etc. I am using a T-Cobber Plus, by the way. I plan to upload pictures of my solder and make a schematic diagram to help troubleshoot any connection mistakes or workmanship issues.

Here is a full printout of the error message in the terminal window:

Code: Select all

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/adafruit_bus_device/i2c_device.py", line 154, in __probe_for_device
    self.i2c.writeto(self.device_address, b"")
  File "/usr/local/lib/python3.7/dist-packages/busio.py", line 121, in writeto
    return self._i2c.writeto(address, buffer, stop=stop)
  File "/usr/local/lib/python3.7/dist-packages/adafruit_blinka/microcontroller/generic_linux/i2c.py", line 49, in writeto
    self._i2c_bus.write_bytes(address, buffer[start:end])
  File "/usr/local/lib/python3.7/dist-packages/Adafruit_PureIO/smbus.py", line 308, in write_bytes
    self._device.write(buf)
OSError: [Errno 121] Remote I/O error

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/adafruit_bus_device/i2c_device.py", line 160, in __probe_for_device
    self.i2c.readfrom_into(self.device_address, result)
  File "/usr/local/lib/python3.7/dist-packages/busio.py", line 111, in readfrom_into
    return self._i2c.readfrom_into(address, buffer, stop=stop)
  File "/usr/local/lib/python3.7/dist-packages/adafruit_blinka/microcontroller/generic_linux/i2c.py", line 56, in readfrom_into
    readin = self._i2c_bus.read_bytes(address, end - start)
  File "/usr/local/lib/python3.7/dist-packages/Adafruit_PureIO/smbus.py", line 179, in read_bytes
    return self._device.read(number)
OSError: [Errno 121] Remote I/O error

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "rfm9x_check.py", line 36, in <module>
    display = adafruit_ssd1306.SSD1306_I2C(128, 32, i2c, reset=reset_pin)
  File "/usr/local/lib/python3.7/dist-packages/adafruit_ssd1306.py", line 220, in __init__
    self.i2c_device = i2c_device.I2CDevice(i2c, addr)
  File "/usr/local/lib/python3.7/dist-packages/adafruit_bus_device/i2c_device.py", line 50, in __init__
    self.__probe_for_device()
  File "/usr/local/lib/python3.7/dist-packages/adafruit_bus_device/i2c_device.py", line 163, in __probe_for_device
    raise ValueError("No I2C device at address: 0x%x" % self.device_address)
ValueError: No I2C device at address: 0x3c
I am stuck and would really appreciate any help that people can offer. Please let me know what other information I can provide. Thanks!

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adafruit_support_mike
 
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Re: LoRa Radio No Connection

Post by adafruit_support_mike »

Post a photo showing your hardware and connections and we'll take a look. 800x600 images usually work best.

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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

Hi, thanks for helping me out. My amateurish solder: [img]PXL_20210613_180757855-min(1).jpg[/img]. The T-Cobbler: [img]PXL_20210613_180842690-min.jpg[/img]. I can make a schematic diagram to make things clearer.
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PXL_20210613_180757855-min(1).jpg
PXL_20210613_180757855-min(1).jpg (620.72 KiB) Viewed 340 times
PXL_20210613_180842690-min.jpg
PXL_20210613_180842690-min.jpg (836.02 KiB) Viewed 340 times
PXL_20210613_180842690-min.jpg
PXL_20210613_180842690-min.jpg (836.02 KiB) Viewed 340 times

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adafruit_support_mike
 
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Re: LoRa Radio No Connection

Post by adafruit_support_mike »

In the first photo, it looks like there's a solder bridge between the pins above the numbers 18, 27, and 22. I also see some exposed gold on one of the other pads.

Redo the solder joints, making sure there are no connections from one pad to the next, and that each joint covers its pad completely.

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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

Much obliged. I took those steps and got as clean a solder as I can manage, but the errors above remain. Supposing the hardware is not the issue, can you recommend any additional troubleshooting steps?

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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

So I made a fritzing of my Lora bonnet - Pi 3B+ wiring. Because the Adafruit tutorials seem to indicate that the bonnet is made to be soldered onto a Pi Zero, I chose a Pi Zero and Pi 3 in my schematic diagram.

Did I make a mistake that would cause the Python code to throw the errors given above? Do I need to add or remove any wires? Would really appreciate any additional guidance folks can offer. Thanks!
Lora_schem.jpg
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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

Anyone out there have ideas? I am well and truly stuck and could really use the help. Thanks!

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jerryn
 
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Re: LoRa Radio No Connection

Post by jerryn »

The bonnet will work on any 40 pin Raspberry Pi -- zero, 3,4
The wiring of the bonnet to any Pi is the same.
Your diagram shows connection between 2 rAspberry Pis, not a Raspberry Pi and the Bonnet. I'm confused by that.
I may just be misunderstanding your setup.

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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

Appreciate the reply, @jerryn. I was operating under the assumption that the bonnet has the same pinout as a Pi Zero. Also, my Fritzing software had the Pi Zero and Pi 3B+ block diagrams. Do you think this initial assumption is correct? Thanks!

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jerryn
 
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Re: LoRa Radio No Connection

Post by jerryn »

Yes. As far as I know Pi zero and the Pi 3 have the same pinouts and the bonnet can connect to either of them.

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adafruit_support_mike
 
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Re: LoRa Radio No Connection

Post by adafruit_support_mike »

That's correct. All 40-pin RasPis have the same pinout.

The only difference is between RasPis that have a built-in Wifi/BLE module and those that don't. RasPis without a BLE module connect the one good UART to the TX/RX pins on the 40-pin header. RasPis that do have a BLE module use the good UART to talk to that, and connect a software-based UART to the TX/RX pins. The software UART's baudrate is derived from the CPU clock, and Raspbian changes the CPU clock speed dynamically based on the processing load.

As a result, GPIO Serial on RasPis with Wifi/BLE is pretty much useless in the default configuration. There are ways to reconfigure the RasPi to make GPIO Serial work, but you have to give up other features to get it.

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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

Hi Mike, really appreciate this reply. Would you recommend getting my hands on a Pi Zero without the wifi/BLE capability instead of using my 3B+, then? That's what I'm thinking of trying, now that I understand that the GPIOs were not being used in the present configuration. Thanks again!

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adafruit_support_mike
 
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Re: LoRa Radio No Connection

Post by adafruit_support_mike »

The RasPi Zero is fun, and at $5 it doesn’t hurt to buy on speculation. If it doesn’t do what you want for this project, you’ll still find a use for it later.

The LoRa Bonnet will be a Zero’s only way to talk to the outside world though, unless you attach something to the USB-OTG jack.

That isn’t necessarily bad though. If you don’t need the Zero to talk to anything but external radios, you’ll be fine.

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bpjmalone
 
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Re: LoRa Radio No Connection

Post by bpjmalone »

Okay, then maybe this will work. I was going to try to use a split-core CT, an ADC, and some resistors to send electric current measurements from one bonnet connected to a Pi Zero to another bonnet connected to another Pi Zero. Without having the components on hand, do you think something like this could work on a breadboard? Thanks a lot for the advice you've given.

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adafruit_support_mike
 
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Re: LoRa Radio No Connection

Post by adafruit_support_mike »

Yeah, a breadboard (or a few) would probably be able to hold all the parts and let you make all the connections.

You might also want to pick up some copper clad:

https://www.amazon.com/s?k=copper+clad+ ... doa-p_1_11

It’s versatile on its own, and when you add mechanical hardware it becomes incredible.. you can solder zinc-plated steel nuts and bolts to it, use brass wire and brazing rod to build support structures, drill and tap it to create planes separated by plastic nuts and bolts, etc. I do most of my prototyping on copper clad, and love the stuff.

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