[ZeROSEro7] SX1276 DIO, ANT and now low power

Last week I improved my LoRa driver by using the IRQ through the DIO pins and greatly improved range. I increased the dBm output to 14 and made sure the RX sensitivity was correctly set. I then played with the CRC and spreading factor parameters to have best range performance. I still have to do an exterior range test with the antenna we will use, but with the dev kit, we were able to receive the signal on the other end of Telecom with all it’s walls.

I am now working on the power consumption, that is to say on sleep modes and wakeup times. Since I am focusing on the spy talk, I preferred the ON base current standby consumption for the nRF to save roughly 100ms on wakeup for only double the sleep consumption. I think this tradeoff is justified because even if the spy talk has low throughput, it should be able to send alarm messages really quickly. I must now try to disable as many peripherals, including the SX12 when I want to save energy. Depending on the algorithm, deep sleep may also be needed later.

I had a good look at the MAC layer from Semtech, but I’m not sure we will be using it. As mentionned above, we will aim towards very low latency and I’m not sure it will achieve that. Moreover, there is a lot of overhead and Everything isn’t completely customizeable. I still need to investigate this more, but for now I think I will design my own TCP-like protocol.

My next step will be to run a GATT server on BLE and I should have all my basic blocks to start the Spy talk software.

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