Hi,
I agree with Barry but disagree about the device required: get a cat, hiinaiwen, it's a pure analog lizard hunter, and very good at it - they check all walls and surfaces for them several times a day.
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Just as seriously as the feline option, I don't know if the lizard problem is indoors or outdoors, but any old white light lamp will attract moths at night, which will in turn attract lizards. Electrocuting might make the lizard explode and be very messy (see what fly zappers do - keep them far away from food areas). Do lizards slip on oily surfaces?
At a guess perhaps the simplest is a pressure sensor and a metallic plate and an LED to attract insects, when the lizard steps onto the plate the pressure sensor senses it's presence, and someone else can think of a way to close the circuit to electrocute the lizard; you could have the pressure sensor trigger a lid on a box. You should look at how UV fly traps work to get an idea, but on a much bigger scale - are they a grid of +V -V and the fly fills the gap to create a short or something revolting like that?
Observation tells me lizards may not be too excited about climbing into a confined space, so for every 1 you trap another 99 will be too shrewd to risk it.