External Motion Detector

Without replace my existing light, I would like to add a PIR sensor detects motion when it turns on. Is this possiblea Thank you.

Yes.

BUT you will probably find the cost is more than buying the complete light unit + RIP! I bought one last week completed for £ 3.99 !!!!!

yep, full instructions come withthe sensor. You can pick them up at any hardware store.

Remember to consult a qualified electrician to install blah blah blah too.