[Krypton]

I don't mean for this to sound like a cry for help (which it is) but here goes...

As part of a first year undergraduate project, I have to design an electronic handheld product that uses an op-amp type circuit. Thus this lends itself to measuring some quantity (light, heat, sound, movement etc) and then producing an output such as a light or buzzer.

I was going to go with a small pocketable light meter for photographic purposes, but this causes lots of problems because numerical displays are off limits (I'm an industrial design student, the electronics I'm learning are the basics) and with LEDs you can only really show the extremes - i.e. too high or too low.

Anyone any ideas for how to refine this into a better product or application, or any off the wall suggestions for entirely different products/projects go ahead.

[Zimphire]

Make a simple theremin out of an op amp. There are schematics all over the place.

Just a op amp, a few caps and resistors.

I think it uses one of those photocell resistors to control the pitch.

[Krypton]

Originally posted by Zimphire:
Make a simple theremin out of an op amp. There are schematics all over the place.

Just a op amp, a few caps and resistors.

I think it uses one of those photocell resistors to control the pitch.

Thanks for your input, I'll look into that.

Just to clarify, I don't have any issues with building the circuit as such, what I'm after is help on finding an interesting product proposal to base the project upon (something consumer orientated, and handheld as already mentioned), or perhaps a viable market etc.

[SVass]

You could design a light that goes off in the dark and stays on in the light. (Once a nameless individual tried to convince the Navy that a warning panel needed a light to announce that the power was out.)

Or you could build an UP meter that lights when vertical. (Useful in a submarine?)

Or you could ?

[tooki]

Originally posted by Krypton:
(something consumer orientated...

oriented -- the verb is "to orient", from which the noun "orientation" is derived, not vice-versa! (There's no verb "to orientate".)

tooki

[Sherwin]

Originally posted by tooki:
oriented -- the verb is "to orient", from which the noun "orientation" is derived, not vice-versa! (There's no verb "to orientate".)

This is common usage here in England Tooki. And seeing as the guy is in England speaking English rather than in the colonies speaking a shoddy approximation...

[olePigeon]

Many boffins died getting us this information.

[alligator]

For a light meter, this would be simple with an LED display. Just have a series of five LEDs, with the middle one being the "right" light level, whatever you may want it to be. Then it could show lower or high light values, with small deviations, of course. This would be useful and very simple to design.

For a while National Semiconductor was giving out free samples, one chip at a time, five per week max. I took advantage of this and stocked up.

[The Godfather]

Can you use an analog gage? That will be the easiest thing to implement. With amp-meter gauges, you would have to make a voltage-to-current converter with the opamp.

[Cubeoid]

Please post a picture of a boffin.

[Sherwin]

No idea what an op-amp entails, but how about making a guitar tuner with a needle gauge?

<needle gauge>
<flat LED><sharp LED>

<note LEDs - to show which string you've switched to>

Like so:

[Zimphire]

Originally posted by Krypton:
Thanks for your input, I'll look into that.

Just to clarify, I don't have any issues with building the circuit as such, what I'm after is help on finding an interesting product proposal to base the project upon (something consumer orientated, and handheld as already mentioned), or perhaps a viable market etc.

http://www.thereminworld.com/schematics.asp