Right now I'm trying to understand how I could (easily) power the heater of my MQ-9 carbon monoxid and gas sensor.
Here is the datasheet: http://www.haoyuelectronics.com/Attachment/MQ-9/MQ9.pdf
It needs 5V for some gases, so I thought I could maybe power the heater via the 5VIN pin (while plugged via usb), since the other output pins have a max. voltage of only 3.3 V?
And to control the power, I could then add a relay switch, which would cut the circuit between heater and VIN (if I only want to measure the gases)?
Or am I completely wrong?
P.S: And no - I don't want to add a 5V power supply additional to the normal USB plugging on VIN :)