It is a solar-powered data collector that records sunlight exposure. This RCM3400-based device is the perfect tool to have on hand when scouting out sites for solar panel installation.
http://www.circuitcellar.com/library/print/1104/Cyliax172/index.htm
allows you to measure light levels using a regular digital voltmeter
http://www.edn.com/archives/1996/081596/17di3.htm
This circuit is yet another design that converts current from a PIN photo diode to a voltage. It has a bandwidth that extends beyond 50MHz.
http://www.discovercircuits.com/PDF-FILES/fetamp0.pdf
converts current from a PIN photo diode to a voltage with bandwidth that extends beyond 50MHz
http://www.imagineeringezine.com/e-zine/hcircuits.html
LED brightness control circuit and a multimeter to compare light levels to LED level
http://avery.home.mindspring.com/LPmeter.htm
http://www.designnotes.com/CIRCUITS/ls-timer.htm
http://www.aaroncake.net/circuits/lightdrk.htm
A UV sensitive photodetector can be realized by using a Siemens BPW34B with a standard transimpedance amplifier. The enclosed schematic shows two different circuits. The circuit on the left is a basic design which can be used for detecting a slowly changing source.
http://www.web-ee.com/Schematics/PIN%20Diode%20Amp/uv_sensitive_photodetector.htm