Controlling relay on generic node

slush · December 13, 2020, 7:21pm

Hello,

I’m trying to control relay on my (battery powered) node running generic node firmware. By following the documentation (GitHub - hardwario/twr-generic-node: Firmware for HARDWARIO Generic Node), I’m able to read various values (temperature, button press), but I’m failing at writing relay commands (failing = node does not respond to any attempt).

I’ve read on How to control remote relay - #2 by Karel that controlling relay is possible only with generic node with power module, but the bcf-generic-node does not mention any constraints about this. However I’d expect some limitation on receiving commands thanks to battery powered operation, but I’m unable to find any details about this.

Thank you for any advice.

Karel · December 16, 2020, 9:12am

Yes, that’s right, the relay can only be controlled in the generic firmware with the version for the power module. We will fix the readme.

slush · December 16, 2020, 8:01pm

Later I’ve found that radio receiving is really enabled only for builds with power module. I’m writing it here for further reference as I spent some time on finding out this.

Karel · December 21, 2020, 7:36am

Yes,
because consumption at continental reception is 10mA it cannot be operated with a battery.

But for custom firmware exist way how listen on battery.
You can set the timeout for which the node listens after the sent message.
When I wrote this function, I sent the temperature and in response to it in Node-RED I set the relay over radio. I think a timeout of 100ms was enough.

github.com

hardwario/bcf-sdk/blob/master/twr/inc/twr_radio.h#L183


uint64_t twr_radio_get_event_id(void);


bool twr_radio_is_peer_device(uint64_t id);


bool twr_radio_pub_queue_put(const void *buffer, size_t length);


void twr_radio_set_subs(twr_radio_sub_t *subs, int length);


bool twr_radio_send_sub_data(uint64_t *id, uint8_t order, void *payload, size_t size);


void twr_radio_set_rx_timeout_for_sleeping_node(twr_tick_t timeout);


twr_radio_peer_t *twr_radio_get_peer_device(uint64_t id);


uint8_t *twr_radio_id_to_buffer(uint64_t *id, uint8_t *buffer);
uint8_t *twr_radio_bool_to_buffer(bool *value, uint8_t *buffer);
uint8_t *twr_radio_int_to_buffer(int *value, uint8_t *buffer);
uint8_t *twr_radio_uint16_to_buffer(uint16_t *value, uint8_t *buffer);
uint8_t *twr_radio_uint32_to_buffer(uint32_t *value, uint8_t *buffer);
uint8_t *twr_radio_float_to_buffer(float *value, uint8_t *buffer);
uint8_t *twr_radio_data_to_buffer(void *data, size_t length, uint8_t *buffer);

slush · December 22, 2020, 11:40am

Thank you for the information. I’ve tested twr_radio_set_rx_timeout_for_sleeping_node and it works as expected!