Hi everybody,
I am trying to monitor an optical smoke detector with the ADC of a PIC18F4520. The sensor feeds off a +24V rail and when they sense smoke, the resistance of the sensor will drop making the consumption go up to about 4mA.
The problem I am having is that I don´t know how to interface the PIC with these sensors to be able to monitor the current safetly and know when they are active.
Could anyone give me some ideas?
I appreciate all your help.
I am trying to monitor an optical smoke detector with the ADC of a PIC18F4520. The sensor feeds off a +24V rail and when they sense smoke, the resistance of the sensor will drop making the consumption go up to about 4mA.
The problem I am having is that I don´t know how to interface the PIC with these sensors to be able to monitor the current safetly and know when they are active.
Could anyone give me some ideas?
I appreciate all your help.