Sending SAADC Data via Bluetooth in nrf52832

RE: Sending SAADC Data via Bluetooth in nrf52832

ovrebekk — Tue, 29 Dec 2020 14:03:26 GMT

I don't think we have done much benchmarking to see how fast you can send packets from an nRF52 device to the nRF24L01+, but it should be possible to send at least one packet every 500us, which corresponds to about 40kHz sampling frequency in your case.

Just keep in mind that this assumes zero packet loss, and that the data is sent and read out efficiently on both sides of the link.

As I mentioned earlier it is critical to observe the nrf_esb_write_payload(..) return code and the frequency of NRF_ESB_EVENT_TX_FAILED events in order to see if the data is successfully transferred to the PRX device.

Best regards
Torbjørn

RE: Sending SAADC Data via Bluetooth in nrf52832

Masoumeh — Wed, 23 Dec 2020 11:10:42 GMT

I am using the nrf24l01+ as the receiver and its packet load is 32 bytes max. so what can be my sampling frequency with these system while my radio is working in 2Mbits/s and my resolution for adc is 12 bits, also i put every 2 samples of the adc in 3 byte of the packet load to optimize the configuration.

RE: Sending SAADC Data via Bluetooth in nrf52832

ovrebekk — Mon, 21 Dec 2020 15:00:25 GMT

Do you ever see the NRF_ESB_EVENT_TX_FAILED event occur, or that the call to nrf_esb_write_payload(..) returns an error?

If you are uploading data to the nrf_esb library faster than it is able to send it out, you will at some point fill up the buffers, and if you ignore this error it will lead to packet loss.

One way to increase data throughput is to increase the size of each packet (on the nRF52 series you can go up to 252 bytes payload), but this will only work if you have nRF52 devices on both sides of the link.

Best regards
Torbjørn