The BPW34 is a tiny, general purpose PiN photodiode.
This photodiode has a ton of uses, one of which is to use it is a mini solar cell to power your project.
The cell is sensitive to a wide range of light wavelengths (430-1100nm), so it should produce power in a number of different settings.

The rated open circuit voltage is 350mV (900nm, 1mW/cm² light source), and short circuit current is 47μA.

These are fun (of course)!
We shined a 940nm infrared LED on one of them and it produced about 0.5VDC open circuit voltage.
Stringing four together in series, we were able to turn an LED on with them.
They'll also produce a small voltage, ~250mV, in a brightly, fluorescent-lit room.

 

Features:

• Package type: leaded
• Package form: top view
• Radiant sensitive area (in mm2): 7.5
• High photo sensitivity
• High radiant sensitivity
• Suitable for visible and near infrared radiation
• Fast response times
• Angle of half sensitivity: phi = ± 65°
• Lead (Pb)-free, RoHS compliant

Dimensions:

• 5.4x4.3x3.2 mm

Documents:

• Datasheet