RAK 7205 - Stops reporting / reports inconsistently

Hi,

I have a RAK 7205 mounted on a vehicle in a farm lorawan setup. It was reporting intermittently for about a week then stopped reporting altogether. I’ve since connected to it via usb and it has now jumped back to life, however even when left in the same spot in direct sunlight in the backyard it continues to miss sending observations. Currently i have it configured to send every 10 mins. Please see the attached graph that shows how often it managed to report over a 3 hour period.

Q. If the device wakes up and fails to get a GPS satellite fix should it still send a lorawan packet? i.e my expectation would be to see a packet every 10mins or so with some being error readings if the device failed to find a satellite.

Q. Any tips for how to debug what is happening here? When it is indoors and connected to my pc i can’t seen any obvious error conditions. I would like to be able to check if it is successfully waking up every 10 mins, if so is it failing to get a satellite fix etc.

Q. Assuming sunny conditions and the solar panel is operating at max capacity what would you expect to be the max frequency you could send observations without running the battery flat? i.e is every 10mins to often?

Q. Basically i was hoping to recreate a ‘strava (iphone app)’ like experience where i would have enough data to map where a vehicle had been and how fast it was going at different points during the trip. My ideal scenario would be reporting sensor observations as often as every 5 seconds while the vehicle is in motion. Is this type of usecase supportable with the RAK7205?

Thanks,
James.

Welcome to RAK forum @jousby :slight_smile:

To answer your questions:

  1. The device will still send LoRa packets even without GPS signal. But of course no GPS data.
  2. The debugging depends on what you are trying to figure out. I am not sure where you get the graph. But probably add another extra device (if you have) that can send every 2 minutes to see if the gateway side and network server is working ok. If your 2nd device continuously transmit and the RAK7205 do not, then it is the device issue and not a GW or LNS related. How far are you from the gateway btw and what LNS (LoRaWAN network server) do you use? Do you own the gateway and have access to it?
  3. This is something need to be tested on the field. We need to get the charging current of the solar panel (probably average for the whole day) then match it to the discharge current of RAK7205 (which will depend on the frequency of sending uplinks).
  4. Every 5 seconds transmission will not work on ANY LoRaWAN devices because of the duty cycle and dwell time restrictions depending on where you are.

Btw, I suggest you update the FW of your RAK7205 in case it is not yet updated - Quick Start Guide | RAKwireless Documentation Center

Hi,

Thanks for the quick reply.

I’ve now done a firmware update but the behaviour remains the same. As in the device seems to wake up at random times not at the fixed sending interval. It does this during the night as well so seems to be unrelated to how much charge is in the battery and how much is being recharged by the solar panel.

I’m using the AWS IOT Core for Lorawan as my LNS with a Laird Sentrius Gateway. The graph above is generated from AWS Cloudwatch logs where I’m recording all the inbound messages. I have several other sensors running on the same setup without problem. I’m fairly confident its not the gateway / LNS setup.

The sensor is setup (at the moment) about 5m from gateway.

I’ll keep trying a few things on my side but if you haven’t seen this before in a RAK7205 perhaps my device has a hardware fault?

What frequency band do you operate? Does it occur only if purely battery powered? Or even when connected via USB (power or data)?

We have issue on RAK7205/RAK5205 that halt transmitting after long time of continuous operation. That is solved already by the latest FW. But in your case, it suddenly occur (the erratic behavior of not transmission).