I am testing the MQ CO sensor linked below
I am measuring the analog output at the end of the 5v cycle,
just before switching the Heater voltage to 1.5volt
I connected 1.5v battery to the NC terminal of the relay and
5v to the NO terminal of the relay and I am using the relay to switch the heater voltage between 5v and the 1.5v. Please check the attachment.
The LED is switching ON correctly according to the assigned time in the program, however, the contacts of the relay does not move. I discovered this when I measured the heater voltage. I always get 5 volts.
When I tested the relay directly with the with the 5v and ground of Arduino, I could hear the switching of the contact, in your opinion, what could be the problem?