Implementing Explorer

I have finally got around to setting up a beehive scale using an Explorer and LoraWan (and it’s working well!).

In the previous configuration which used an Autonomo with GPRS modem, the device slept for 1 hour, awoke and took a reading, sent it off and then went back to sleep. Once a day it synchronised the RTC with an Internet time server.

I would appreciate some help with a couple of questions about the Explorer.

  1. Do I need to switch off the Lora and Bluetooth modules or does putting the board to sleep achieve this?

  2. How do I get a clock sync signal via Lora to set the RTC (I’m using TTN and the CayenneLPP library). I realise that transmissions are timestamped at the gateway so it doesn’t really matter, but it would be good to have the device wake up at a predictable time.

  3. The coin cell battery seems to run down quickly. Am I right in thinking this is only 20mAh and perhaps rather underpowered for running indefinitely with a solar panel with only intermittent sunshine each day? The Autonomos typically went forever using a 1200mAh battery with a panel. Or does the Lora modem use so much less power than the GPRS modem that this is enough? I haven’t been able to measure the current consumption yet, I’ve ordered an INA219 so that I can run some checks.

Thanks in advance, Andrew

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Dear @awootton,

  1. In our library you have a sleep command for the LoRa module.
    Depending on if you use the BLE, you can put it into sleep or shut is down completely.

  2. There is no network time sync in LoRa
    You can send a downlink packet with a timestamp.

  3. You can use the 1200mAh battery also on the explorer.
    You need to switch the pin from Internal (coin cell) to external (lipo) in order to let it work on the 1200mAh battery.

LoRa uses much less then GPRS, but battery lifetime is not just the connection type. All sensors and microcontroller need power.

Best regards,
Jan

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thanks Jan for the prompt response.

I have seen the “sys sleep nnn” command to put the Lora to sleep, but this seems to be setting a fixed no of milliseconds. Whereas I am putting the whole board to sleep and then wanting it to wake up and then wake the Lora modem. Also I’m not using the RN2483 library because it doesn’t seem to work with the early version of SodaqOne and Explorers that I have (discussed in “Sodaq One Setup fail” thread on the forum).

So do I just set “sys sleep 5,000,000” ? (something greater than 3,600,000) What is the wake up command?

I have been using a 1200mAh battery. I just wasn’t sure whether this was necessary or if I could get away with the coin cell battery if I could get the sleep current down.

Hi @awootton,

The library should work on all boards with the RN module.
Can you tell me what RN module you have, the revision of the sodaq board and the firmware on the RN module?

All commands can be found here.

In chapter 2.3.1 you can find the sleep command.

Best regards,
Jan