Hand wired flexible sensor

A project log for No battery NFC air pressure sensor

Measure tire or ball pressure with your smartphone

CaptMcAllisterCaptMcAllister 03/12/2016 at 20:240 Comments

March 12, 2016: TI got wind of my project and was kind enough to send me some flexible patches that they had made. I finally got around to hand wiring a pressure sensor and voltage regulator onto one of them, and I'm pretty proud of my work (pictures below). I did this one quite a bit different. There's no differential amplifier, so my signal is very tiny AND it's biased toward the high rail, so I can't use the gain stages inside the IC. The pressure signal is measurable though. I don't think I would do away with the op amp if it weren't such a pain to hand wire in. I also used a capless voltage regulator to provide me with a more predictable voltage than the RF430 can. This way, I don't have to spend ADC time (or more hand wiring) measuring the pressure bridge's reference voltage. This one is going to get the components epoxied and it's going into my BACK tire. It's about to have a hard life. We'll see how it turns out.

On a related note, the original sensor is still going strong after 90 miles in the front tire. Still no leaks, still no problems.