LoFence V2 is an updated version of the original LoFence tackling a few shortcomings.
The main improvements are:
- case lid can be opened while main body is mounted,
- two batteries for a longer operating time,
- battery deep discharge protection using an activation circuit with a button triggered from the firmware when batteries run low,
- fully revised firmware with ability to change operating parameters by downlinks.
Other things changed are:
- Exchange RN2483 module for Dragino LA66.
- I always had some problems with the RN2483 though serial communication protocol was easier to work with.
- LA66 has antenna connector on board so I don't have to care about a correct antenna circuit which also has to follow the guidelines to not to violate regulatory approvals.
- LA66 is a little cheaper.
- Implement probe resistor divider erratum.
- Optimized for assembling.
- Changed various components to SMD variants.
- Switch to buck-boost converter for power supply.
- Use clamps for holding batteries instead of full holder.
For information how to build a LoFence V2 device see the hardware repository.
For information how to build, upload or configure the firmware see the firmware repository.
Do not let the debug LEDs activated during normal operation!
They need a lot of current compared to the overall device's current usage. So if activated they drastically reduce the battery runtime to just some weeks or even days.
The LoFence V2 is equipped with an activation circuit allowing the device to deactivate itself if the battery voltage goes under a configured level (3200mV by default for 5 cycles or 3100mV as an absolute minumum) to prevent the battery from deep discharge.
Therefore the device does not automatically activate if a battery is put in but you have to push and hold the ACTIVATE button for at least 1 second.
If the debug LEDs are activated the Idle, Measure and Transmit LEDs indicate that the activation process has been completed when they goe out and the Clock LED starts to blink at one seoncds intervals.
After activation the device tries to join (re-join) the network, LoRaWAN counters are reset. The Transmit LED then should start blinking at half a second intervals indicating that the device is trying to join a network. After a 10 minute timeout the Transmit LED will start to blink quickly indicating that the device could not join a network. Check your gateway and network server if you see packets from the device and maybe you get some info why it cannot join, often there is a problem with the DevEUI or the application key. The device must be reset to retry joining in this case.
If the Transmit LED is constantly on then there is an issue with the communication between the MCU and the LoRaWAN module probably because of a hardware issue, defective soldering or a damaged LoRaWAN module.
If joining succeeds the device will immediately do the first measurement and after that transmits the first uplink.
While transmitting uplinks the Transmit LED will be on constantly.
To reset the device push the RESET button. After a reset the device has to be activated again.
A reset is just the same as removing all batteries and put them back in and activate the device.