In order to help his friend prepare for a talk at DEFCON this weekend, [Craig] built an IR photodiode amplifier circuit. The circuit extended the detection range of the hack from a few inches to a few ...

Optical systems have many unique attributes that make them useful for range detection and communications, but often the optical signal needs to be converted to an electrical signal as part of the ...

This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam or IR beam focused on to the Photodiode.

1. This circuit uses a JFET to bootstrap the cathode of the photodiode. It eliminates the effect of diode resistance and capacitance. This improves bandwidth and reduces noise, but puts a dc voltage ...