“A photoresistor or light dependent resistor (LDR) or photocell is a resistor whose resistance decreases with increasing incident light intensity; in other words, it exhibits photoconductivity.” wikipedia
I keep a large supply of these inexpensive sensors on hand.
You can find them available at DigiKey.
eTextile Breadboards0
Reprogramming an ATtiny450
Photosensor Circuit0
Push the Blue Switch!0
Conductive Thread from Syscom0
4cm x 6cm PCB from eBay seller czb67219600
Universal Printed Circuit Boards from eBay0
Heart Sensors0
Vector Prototype Boards0
Programming ATtiny45s for PIF0
Speaker Circuit from a Mini Travel Speaker0
ATtiny 45 Broken and Exposed0Conductive Thread from Syscom04cm x 6cm PCB from eBay seller czb67219600
Universal Pen Holder with Brother ScanNCut20Universal Printed Circuit Boards from eBay0
Making Circuit Samples with the Brother CutNScan0
NFC Tags0
Workbench at Ljudmila – Preparing for PIF0eTextile Breadboards0Reprogramming an ATtiny450Photosensor Circuit0Push the Blue Switch!0Conductive Thread from Syscom04cm x 6cm PCB from eBay seller czb67219600Universal Pen Holder with Brother ScanNCut20