hacking wiimote trigger

[justintylerclark]

Hi All,

I am a noobie trying to attach a wiimote to a rowing machine in order to use the rowing machine as an exergaming peripheral.  My question is whether it would be possible to wire the A or B trigger to the sensor in the rowing machine, such that when the rower is used at a certain minimum pace, the pulses coming from the rowing machine sensor are reconfigured through an IC as a continuous application of the Wiimote trigger.  The reason one would need to do this with a driving game is of course that one holds down, rather than pulses, the trigger button in order to apply the gas.

Anybody have any suggestions?  I'm thinking of using a potentiometer to calibrate the pulses from the rowing machine sensor, so that the machine has to be rowed at a minimum rate.  But what I don't know is how to set up the circuit that will convert those pulses into a continous signal to the trigger.

Thanks guys.

 

[hyper999]

yes it is possible however without knowing what kind of sensor the rowing machine uses it is difficult to help you

[Famas]

could ths be done like basic rf with a 555 timer and a poteniometor?

[justintylerclark]

The sensor seems to be a simple reed switch.  Like an exercise bike, there's a wheel that triggers (closes) the switch once per revolution. 

Were I to use the 555 chip, how would I be using it?  What sort of function would the chip be performing?

[hyper999]

i dont think a 555 timer is suitable for what you want
so what you want is when the rowing machine being used above a speed threshold a button on the wiimote is held down yes?

are you capable of writing code and programming an ic? or are you looking for a more hardware based solution?

[frenulem - No.5417]

Just Blurting this out, But a capacitor could smooth out the signal This could be useful

[justintylerclark]

"so what you want is when the rowing machine being used above a speed threshold a button on the wiimote is held down yes?"

Exactly. 

I've never programmed an IC.  I can read a basic circuit diagram and use a voltometer and a soldering iron, but that's pretty much the extent of my electronics skills.

[hyper999]

ok well in that case your probably better off with a hardware solution
so FOOKz? any input?

[frenulem - No.5417]

A capacitor will work, but it's just finding the calculations you need

[FOOKz™]

Sounds to me you want a frequency counting VCO that controls a one-shot. (reverse frequency modulation)

hmmmm. let me think about this one tonight, im going out atm. I know its possible with a 555 timer and a few transistors.

[802Chives]

there are chips that convert frequency to voltage like a LM2917.   it can be done with op amps as well. 

sounds like this project would be good microcontroller candidate so the peripheral could be reconfigured for different games. 

any way you do it you will probably find this app note from Microchip useful:
http://ww1.microchip.com/downloads/en/AppNotes/00795a.pdf

that app note uses the TC9400 chip:
http://ww1.microchip.com/downloads/en/DeviceDoc/21483d.pdf

[hyper999]

ok that looks great chives
so if we use an lm2917 could we just hook that up to a comparator like circuit and then we could adjust the threshold with a pot yes?
this sounds like a really good mod it could work with nearly any console and you could use it on things like excercise bikes , and tredmils aswell!
this would make a great RnD project

[FOOKz™]

the LM2917 seems like it will do the job well. i don't have any laying around anywhere so i cant test.

nice find Chives this is going into my bookmarks. 

a VCO from a 741 op amp is the best way to go IMHO since they are readily available at Radioshack and online.

so if we use an lm2917 could we just hook that up to a comparator like circuit and then we could adjust the threshold with a pot yes?

both Input signals to the comparator will need to be in phase greater than 90% to be effective.

How is it supposed to compare frequencies together if they aren't in phase. I'm stumped, i never ran into a problem like this before.

maybe you have a calibrated RC circuit in a one-shot. the one-shot gets triggered by your input button. when the button is held long enough the output of the one-shot is constant. In contrast; if the button is pressed faster the output of the one-shot becomes more frequent and charges a large capacitor quicker. If the input frequency is slow then the large capacitor won't charge at all.
SO where am I getting to this? just read on.
When the larger capacitor is charged to a certain calibrated point it says "hey your one-shot has reached a high enough frequency!" so you discharge your capacitor into some kind of PIC input or a transistor control circuit to make it useful and do something. (preferably controlled by a MOSFET because what if you want to hold your cap's charge until a certain point).

[hyper999]

congratulations fookz you have baffled me once again :P

what i was thinking was use a circuit like this:

but replace the ldr with the lm2917 and the transistor would switch the button not an led

[Modded Matt]

are you guys just now figuring out the chives is the :censored:ing man???

[FOOKz™]

I think I'll just leave this here.

http://www.national.com/ds/LM/LM567.pdf