Datasheet

For most light-sentsitive applications like "is it light or dark out", "is there something in front of the sensor (that would

block light)", "is there something interrupting a laser beam" (break-beam sensors), or "which of multiple sensors has

the most light hitting it", photocells can be a good choice!

Some Basic Stats

These stats are for the photocell in the Adafruit shop which is very much like the PDV-P8001 (https://adafru.it/clX) .

Nearly all photocells will have slightly different specifications, although they all pretty much work the same. If there's a

datasheet, you'll want to refer to it

Size: Round, 5mm (0.2") diameter. (Other photocells can get up to 12mm/0.4" diameter!)

Price: $1.00 at the Adafruit shop (https://adafru.it/aIH)

Resistance range: 200KΩ (dark) to 10KΩ (10 lux brightness)

Sensitivity range: CdS cells respond to light between 400nm (violet) and 600nm (orange) wavelengths, peaking

at about 520nm (green).

Power supply: pretty much anything up to 100V, uses less than 1mA of current on average (depends on power

supply voltage)

Datasheet (https://adafru.it/clX) and another Datasheet (https://adafru.it/clY)

Two application notes on using (https://adafru.it/clZ) and selecting photocells (https://adafru.it/cm0) where

nearly all of these graphs are taken from

Problems you may encounter with multiple sensors

If, when adding more sensors, you find that the readings are inconsistent, this indicates that the sensors are interfering

with each other when switching the analog reading circuit from one pin to the other. You can fix this by doing two

delayed readings and tossing out the first one.

See this post for more information (https://adafru.it/aKL)