hand crank tachometer with computer interface

[Allen]

As part of an arts project I'm putting together a machine where by an
individual can control the speed of a digital video via a hand crank.

The software I have in hand, but the hardware I don't, or more
specifically the interface between the hand and the computer.

What I could really do with is a bit of a hand held approach to the
best method of getting from my wheel to my port.

Ideally I'd like to use something with no friction at the crank end,
probably some sort of IR encoder like in a mouse. I have in fact tried
just using a mouse but because it's calculated through the mouse
divers I quickly run out of screen space.

What I don't get is what I need in between the encoder and the port,
and what that will actually give me at the port end, a count of some
description I'm assuming

I hope at least some of that makes sense, and hope you can help.

Allen

 

[happyhobit]

Hi Allen,

How can you have the software when you don't know what the hardware will be?
Usually you decide on hardware and then design software to suit. What does
your software require / expect?

If you're doing the programming, use a 'rotary encoder' ($5.00), check out
the 'Digikey' catalog online, connected to the 'handshake' signals on the
serial or parallel port. The rotational speed of the encoder will be based
on the time between the pulses.

Jay

 

[happyhobit]

Allen,

To more accurately answer your next the last paragraph;

Encoders put out pulses. Software translates those pulses into whatever the
program requires and in whatever format it expects.

What does your software require / expect.

"Quality is conformance to specification". It's your job to provide that
specification. It's not easy to ask a good question.


Jay

 

[R. Steve Walz]

As part of an arts project I'm putting together a machine where by an
individual can control the speed of a digital video via a hand crank.

The software I have in hand, but the hardware I don't, or more
specifically the interface between the hand and the computer.

What I could really do with is a bit of a hand held approach to the
best method of getting from my wheel to my port.

Ideally I'd like to use something with no friction at the crank end,
probably some sort of IR encoder like in a mouse. I have in fact tried
just using a mouse but because it's calculated through the mouse
divers I quickly run out of screen space.

What I don't get is what I need in between the encoder and the port,
and what that will actually give me at the port end, a count of some
description I'm assuming

I hope at least some of that makes sense, and hope you can help.

Allen

 

[Rich Webb]

As part of an arts project I'm putting together a machine where by an
individual can control the speed of a digital video via a hand crank.

Do a web search on "optical spinner".

A good do-it-yourself guide for building one is at
http://www.arcadecontrols.com/files/Miscellaneous/spinner.pdf