reading signal strength in firmware nrf91

[Vojislav]

Hi, 

I am trying to read signal strength inside my code. At the moment I know I can do this with AT commands:

AT+CESQ
+CESQ: 99,99,255,255,255,46
OK

RSRP = -140 + 46 = -94 dBm signal strength

And I also saw there is something implemented in the asset tracker application. My question is: Is there a function to read such parameter or how to do it if there is no such thing?

Thank you.

Voja

[Håkon Alseth]

If that is the only thing you're interested in, just send the at command and parse the response to filter out the RSRP.

If you need more parameters, have a look at this library: https://github.com/NordicPlayground/fw-nrfconnect-nrf/tree/master/lib/modem_info

 

Kind regards,

Håkon

[Vojislav]

Hi, 

I am trying to do this, but there is no result:

void get_signal_strength(void){

        const char signal_strength_command[] = "AT+CESQ";
        char cmd_rcv_buf[50];
        enum at_cmd_state *err;
        at_cmd_write(signal_strength_command, cmd_rcv_buf, strlen(cmd_rcv_buf), err);
        printk("state: %d   ", err);
        printk("answ: %s \n", cmd_rcv_buf);
}

Of course, I am connected to the NB-IoT network before calling this function. 
Serial output is:

state: 0   answ:  

Do you know what might be the problem?



Best regards,
Voja

[Håkon Alseth]

Try something like this:

void get_signal_strength(void)
{
	const char signal_strength_command[] = "AT+CESQ";
	char cmd_rcv_buf[50];
	enum at_cmd_state state;
	int ret = at_cmd_write(signal_strength_command, cmd_rcv_buf, sizeof(cmd_rcv_buf), &state);
	if (state == AT_CMD_OK) {
		printk("answ: %s", cmd_rcv_buf);
	}	
	printk("state: %d, ret %d\n", state, ret);
}

[Vojislav]

Hi Hakan, 

Thanks for the help, also one more thing needs to be changed. sizeof will return 0 because there is nothing in the buffer. 

here is the function that worked for me:

void get_signal_strength(void){

        const char signal_strength_command[] = "AT+CESQ";
        char cmd_rcv_buf[50];
        enum at_cmd_state state;
        at_cmd_write(signal_strength_command, cmd_rcv_buf, 50, &state);
        if (state == AT_CMD_OK) {
            printk("answ: %s", cmd_rcv_buf);
	}	
        printk("state: %d, ret %d\n", state);
        
}