The H8054 Mini PIR motion detection module is designed to provide basic motion detection to your project.
This is a very small light sensor. A photo resistor (also known as a photodector, or photocell) changes resistance depending on the amount of light it is exposed to.
The HC-SR501 is a passive infro-red (PIR) sensor which is used to detect motion based on the infrared heat in the surrounding area.
This is the chain and sprocket kit for the IG42-DB4 robot platform. It includes 10 tooth and 15 tooth sprockets, 5 feet of chain, and 4 connecting links.
Use these roll pins to fix sprockets to a shaft and keep them locked in place.