I'm doing a project to try to replace the main board for an old stationary bike with an arduino. Ultimately it's to interface with some bluetooth devices. I can't figure out how the heart rate monitors on the bike read heart rate. There are two wires that go to the two plates on the grip, but nothing i test with a multimeter gives me any consistent results.
Does anyone know how these things work, or how i can use a newer heart rate monitor and attach it to the existing grip? The sensors i see on amazon have 3 wires. All my googling only shows me how to wire up the 3 wire sensors and get them to work with arduino rather than schematics on how the older bike sensors work.
I would guess one of the 3 wires is ground. That is probably attached to whatever passes for the bike's ground. You didn't mention if it is plugged in or not.
The bike's control panel runs off 3.3v via 2 AA batteries. I could feed that board with 3.3v from the arduino to power it, but I'll likely just remove the old board completely, other than re-using it's buttons since they are mounted in the right places.
Those are likely to be electrical pickups (for analog inputs), and any signal resulting from holding the grips would probably be too small for your multimeter to measure.
