going to make automatic door opener need advice

lOk im building a 12 volt automatic door opener ive figured out what im using a 12 volt powered antenna mask door will bebe light weight plastic or plrciglass on a trac and roller and im looking for a 12 volt motion sensor that will open at the chickens motion kinda like a house porch light with motion sensor but ran off of 12 volts and a solar cell input welcome