Piggy-backing PAS signal to send Cadence data to Bike computer

[jokskot]

Does anyone have any thoughts on tapping and processing the PAS signal and sending the processed signal by bluetooth (?) to a bicycle computer. This might be a tidier, and certainly more elegant, solution, than using a separate magnet on the crank and a sensor on the seat tube or chain-stay.

 

[Woosh]

Does anyone have any thoughts on tapping and processing the PAS signal and sending the processed signal by bluetooth (?) to a bicycle computer. This might be a tidier, and certainly more elegant, solution, than using a separate magnet on the crank and a sensor on the seat tube or chain-stay.

if you mean sending PAS signal to a speedometer? no, that won't work when you are freewheeling.

 

[jokskot]

I

if you mean sending PAS signal to a speedometer? no, that won't work when you are freewheeling.

I should have been more specific I mean Cadence.

 

[Woosh]

I

I should have been more specific I mean Cadence.

the signal stops when you are not pedalling. It may be useful for a heart rate monitor but useless for a speedometer.

 

[jokskot]

the signal stops when you are not pedalling. It may be useful for a heart rate monitor but useless for a speedometer.

I recognise that there will be CADENCE data only when I'm pedalling. I can't see how one would derive heart rate data from the PAS!

 

[StuartsProjects]

What external input signals does this 'cycle computer' accept ?

 

[jokskot]

The "cycle computer" is a free Android app. named SuperCycle:

SuperCycle Bike Computer - Apps on Google Play

A GPS & Bluetooth bike computer to track, analyze and map your bicycle rides.

play.google.com

and I unreservedly recommend it for logging in-ride date

It accepts a Bluetooth signal for heart rate, speed and cadence from a range of commercially available sensors.

My thought, as well proving an interesting development exercise, is that speed is freely available from the phone GPS. Cadence is available from the magnet passing the Hall sensor at the bottom bracket, but would need to be processed - probably by dividing by some constant related to the number of magnets in the PAS and be sent as a Bluetooth signal to the Smart phone.
Heart rate measurement and processing might come next!

 

[StuartsProjects]

Well, in theory its not much of a problem to divide the PAS pulse train by the number of magnets on the disk and simulate a single pulse that might be produced from a single magnet and sensor on the crank and then transmit it as some form of Bluetooth signal.

However is that 'free Android app' readily customisable, by the user, to accept inputs, over Bluetooth, from custom DIY sensors ? Are the exact details of the applications interface protocols available ?

What your suggesting might well be an 'interesting development exercise' as long as you have a fair bit of background in microcontrollers and application development stuff.

 

[Bikes4two]

An interest project if you're into making up circuits on PCBs mounted in say, 3d printed boxes, but I doubt the end result would be more 'elegant' than a bespoke solution from someone like Garmin.

Let us know how you get on though.

 

[StuartsProjects]

An interest project if you're into making up circuits on PCBs mounted in say, 3d printed boxes, but I doubt the end result would be more 'elegant' than a bespoke solution from someone like Garmin.

Indeed absolutly.

Can be fairly easy to work on and design a prototype, but producing a reliable 'product' that will cope with the long term stress of all the bouncing around and exposure to damp and water, is not so easy.