There were threads about these on FR, oh about 15-16 years ago. Which prompted me to remove the plastic casings from such items as books, consumer electronics, OTC medicines. They basically inert with no onboard power source and can only pong back to query power beam broadcast from detection devices, such as at exits, registers, hand held scanners.
Oh, and of course from veterinary scanners. Should Nurse Cratchett approach you with one of these...it's time to be nervous.
All the new credit/debit/security cards contain far more read/write data memory...it's whats in your wallet.
From there we progress to video pill cameras, which have their own tiny LED lights for the fantastic voyage through your esophagus, stomach, small intestine, colon and ultimate may light up your toilet bowl for a brief journey looking for Nemo...til the onboard battery dies.
These transmit some 50-60k images to paste on terminal leads, much like EKG leads to digital recorder carried by the patient. That's about 6-8 hrs of captured images. When questioned Katie Couric responded, " Where's the drama? I mean, you swallow it with a glass of water and what then? What the entertainment factor, it's all about ratings you know."