Photo Cell CdS Photoresistor 10pcs - LDR Pack starter kit v3 uFL connection for external passive

uFL connection for external passive GPS & external GSM antenna

or playback projects

and periodic checking if you want stable readings

Can I use this with a standard Arduino and XBee shield

The Solenoid JF-0530B Push Pull Open Frame Mini Valve Electromagnet is a practical solenoid valve from Circuitrocks for students

Photo Cell CdS Photoresistor 10pcs - LDR Pack starter kit v3 uFL connection for external passiveCdS cells are little light sensors. As the squiggly face is exposed to more light, the resistance goes down. When its light, the resistance is about 5 10K, when dark it goes up to 200K. To use, connect one side of the photo cell (either one, its symmetric) to power (for example 5V) and the other side to your microcontroller's analog input pin. Then connect a 10K pull down resistor from that analog pin to ground. The voltage on the pin will be 2. 5V or