I was looking on the internet how to get the RF signal strenght between a transmitter and a receiver, but until now I could not find anything that could help me.
The main idea is use the APC220 module (I have this on hands), or other to create a simple signal tracker where as I have the high signal strenght, I'll get close to the transmitter! I know that's not accurate, but I would like to know if it's possible and how to get and show on serial monitor / LCD the RF signal strenght.
Do you know it is not monotonic either? That means that weaker signal could be received when it moves closer. Distance is not the only factor in signal strength.
That particular module does not have any signal output for signal strength. If you could get hold of the schematic you might be able to locate a signal called the AGC, Automatic Gain Control, that is proportional to signal strength but it might not be accessible.
Many radio modules have an RSSI output although it is frequently digital and must be read from the radio.. I'm using RFM12B radio's and they have an analog RSSI output that looks useful as it isn't a slot in some register in the radio... It's the filter cap for the Analog RSSI indicator available right on top of the radio.
Do you know it is not monotonic either? That means that weaker signal could be received when it moves closer. Distance is not the only factor in signal strength.
That particular module does not have any signal output for signal strength. If you could get hold of the schematic you might be able to locate a signal called the AGC, Automatic Gain Control, that is proportional to signal strength but it might not be accessible.
Thanks Mr. Grumpy_Mike for your reply!
By the way, do you know if there's a way to build a low cost RF tracker ?
Docedison:
Many radio modules have an RSSI output although it is frequently digital and must be read from the radio.. I'm using RFM12B radio's and they have an analog RSSI output that looks useful as it isn't a slot in some register in the radio... It's the filter cap for the Analog RSSI indicator available right on top of the radio.
Bob
Thanks Bob for the information! I'll check out the APC220 that I have, and also I'll check out the module that your're using "RFM12B".
Let me ask you a question, what's the range and power of the module RFM12B ? Could you share some code how to get the RSSI ?
Hi there, by the way I found this code... I'll try it and solder a wire between the antenna and the capacitor to check out what's happens!
/*
PortmannFilter.pde
This is a filter for smoothing RSSI-Measurements. The filter ignores unusable data and smooths it.
Please note that the given voltage in a Arduino-Microcontroller environment is about 1.5V.
Author: Cédric Portmann (cedric.portmann@gmail.com.)
Copyright (C) 2013 Cédric Portmann
*/
void setup() {
Serial.begin(9600); // initialize serial communication at 9600 bits per second
}
void loop() { // the loop routine runs over and over again forever
int sensorValue = analogRead(A0); // read the input on analog pin 0
float voltage = sensorValue * (5.0 / 1023.0); //convert the value to Voltage
int sensorValue2 = analogRead(A0); // read the input on analog pin 0
float voltage2 = sensorValue2 * (5.0 / 1023.0); //convert the value to Voltage
if(voltage > 1.7 && voltage == voltage2) // Ignore data with a voltage less than 1.7, because of the given voltage in a Arduino-Microcontroller environment.
{
Serial.println(voltage);
}
}
You need to supply that current to the hungry devices somehow bypassing the arduino. Which is inconvenient.
Let me tell you. Nothing.
You can't measure recieved signal strength by attaching a capacitor to an antenna.
By the way, do you know if there's a way to build a low cost RF tracker ?
I do know that there isn't one. Sorry but people have been trying to do this for years. The closest you can get is a Zigbee mesh network where the recieved signal strength from many receivers is processed to give you a rough idea of location. Check out the stuff from TI on this.
Hi Saomart:
You have get through APC220 already?
As I know, APC220 is a little old solution, do not have function of RSSI, I know a device is compatible with APC220, and it have RSSI function. It is ne need to change the hardware to alternate APC200.