Hardware Reference
In-Depth Information
Figure 17-4:
IR
phototransistor
detector wiring.
If the circuit doesn't work, check the wiring. Use a multimeter set on resistance to check the
resistance of the joints - it should read a few ohms at the most. It's also worth checking that
the polarity is correct - that you've connected the IR LED and the phototransistor the right
way around. Some digital cameras are sensitive to IR, so you might be able to use one to “see”
if the LED is emitting IR light.
After you've checked that your sensors work, it's time to mount them in your bird box.
Mounting the Sensors
You could build your own bird box from plans (such as those that are available online) or buy
a ready-made one from a garden centre or elsewhere. Either way, you will need to mount the
emitters and detectors near the entrance hole.
It is important not to create a perch for predators near the entrance to the nest box, or they
could attack the birds in your box. With this in mind, so that the front face around the
entrance remains lat, and to provide some protection to the electronics, it's best to sand-
wich the sensors in layers of plywood.
