tronnyjenkins 

Purchased a Trek 1500 and I have no idea what computer sensors are mounted. If it's cheap ok eBay, might grab the computer itself.

For sure says Cateye. What's the sensor forward of the tire for?

skycomag

that might be a cadence sensor and the rear one looks like a speed sensor.
check the pedal on that side for a magnet on the crank arm or inside where the pedal's attach to the crank arm.

philbob57

The first photo shows a sensor used for the Solar CC2000 and probably some others. The 2nd photo is different, though. It doesn't look at all like the equivalent part on my C2000.

tronnyjenkins 

Anyone else have a clue?

Athens80

The first picture matches the cadence and speed sensors on a wired Cateye unit I remember from some years ago. There should be matching magnets on a rear wheel spoke and on the left crank arm.

I don't recognize the mount on the handlebars for the head unit at all, however.

If you go with a wired computer, please use cable ties instead of that electrical tape to hold down the wires. That tape isn't neat and it leaves the wires hanging out susceptible to damage.