Chasing the puppy with an Arduino, breadboard, RC522 lots of wires and mains supply was impossible, so we tried the other (older, slower) dog first. Not a bleep, ping or twang, nothing (except some threatening looks from old grumpy!); then my friend admitted he might not actually be chipped – but that wasn’t until after I had risked life and limb trying to scan him!

So back to the puppy! Eventually we had him distracted with the right toy and scanning was started. The chip was probably in his neck but he insisted on laying on his back which made things difficult. But we persevered, left side, right side, head, then wider afield; back, flank, tummy; not a squeak (except from the puppy which loved the attention). Surprisingly the fragile assembly held up despite the puppy trying to eat it, but eventually we had to give up.

Being a proper engineer, I then decided to do some actual research, I could have done it while waiting for the stuff to arrive from China (or even before ordering it) but where’s the fun in that? It didn’t take long to discover the chip might be on a different frequency or system to the cards that the RC522 worked on, and also the RFID might not have the range I would need (the cat flap might have something special to boost its range).

So, still undaunted, I will carry out more research and crack this, but it’s not going to be as simple as I imagined, the story continues…