These devices can be attached to electric timers, to turn them on at dawn, when the bats would be returning to your house after a night of flying and hunting, and / or during the day, when the bats would be resting and roosting in your building. Or they can be attached to motion-sensing devices which would turn on the electric appliance when the motion of flying bats is detected.
The object of these techniques would be to disrupt or disturb the bats’ resting and roosting places in such a way as to cause the bats to move to another, more peaceful location. The success reports of these methods to get rid of bats is quite varied, from complete success to complete failure. These mixed reports are no doubt related to the very many specific factors that are involved, including the type, amount, intensity, proximity, intrusiveness and reliability of the disturbance that is generated.
If the location where your bats have moved into is small, and these electric appliances can be situated without too much trouble, you might want to give these techniques a try. Also, these could be coupled with other techniques, like hanging strings of cans, plastic bottles, balloons, aluminum foil, in the bats’ roosting places. An electric appliance, like a fan, could cause these hanging items to move, possibly disturbing the bats enough to move out of your building.
If you are able to get rid of your bats with these techniques, be sure to keep in mind that your bats will reliably try to get back into your building. And, other bats may choose to move into your building, as well. To prevent this from happening, be vigilant in sealing up and “batproofing” your building.
Also, remember to take care of cleaning up the unsanitary excrement, after you get rid of your bats.