Using hologram with a SARA-R410M devkit on Linux


#1

Hi,

I have a u-blox EVK-R4 devkit with a SARA-R410M-02B which I believe is the same module used in the NovaM that is available for preorder. I am evaluating it for including in a product that will be using Hologram.

When I call the hologram.network.connect() method. It returns: “PPPError: Modem hangup - possibly due to an unregistered SIM.” and then if I try to rerun the code it returns: “Unable to detect a usable serial port” and has to be power cycled for the serial to reconnect.

The SIM card is showing up as being live in the hologram dashboard so something is connecting but not to a usable state.

For now I am running on a Linux Mint 19 desktop but this will be deployed into a yocto linux based i.MX8 device.

What are some troubleshooting steps I can run through for both the initial connection failure with PPP as well as to make the serial connection more reliable. I am currently using the direct USB connection to the module.

Thanks


#2

I’d double check from one of the Hologram employees who reply on this forum but based on:

I dont think the Hologram SDK will work with your setup. Per Reuben “The SDK is entirely written to only detect modems that are mounted on the USB port” so I dont think it searches for Compatible modems on any COM ports. Note that even though most devices interface with the computer on a USB cable they are seen as virtual COM ports. I think Reuben means something different here.

Secondly, double check you have the latest SDK, it looks like support for the R410M may have come with v0.8.0 on changelog dated 7/19 per: https://github.com/hologram-io/hologram-python/blob/c1af4988be88e963096634dc10ad5c3e19053559/CHANGELOG.md

Best of luck!, and definitely wait to hear from Hologram for a definitive answer.


#3

Hi Andrew,

I am using the latest SDK which has R410M support.

I also am connected via the USB port the same as the Nova designs and I am planning on using the USB interface in production with the i.MX8 as well. I am not planning on using the UART interface.
It shows up as /dev/ttyUSB0 and /dev/ttyUSB1 on my system.

Thanks,

Kevin


#4

Hmmm, well then I’m stumped. Sounds like it is setup correctly


#5

Hey @kevlan does the hologram send command work? We’ve seen some issues with ppp setups on non raspbian systems.


#6

Just to provide more of an explanation, that command doesn’t use ppp but uses the AT commands on the modem for opening and writing to a socket.


#7

Thanks for the suggestion. I’m having other serial issues on my laptop so I have given up on that for now. The serial connection seems much more reliable from my yocto linux based platform that this will eventually be integrated with so I am going to use that for further testing.


#8

Just to follow-up with this. I was able to get the SARA-R410M module working with a yocto linux build so I will not be working anymore on getting it working on Linux Mint.