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136  Forum 2005-2010 (read only) / Interfacing / Re: LED light gate on: August 16, 2010, 11:52:52 am
Thank you Rugged.

I think I am all set now.
137  Forum 2005-2010 (read only) / Interfacing / Re: LED light gate on: August 14, 2010, 01:25:24 pm
Hi Rugged, thanks for your help. You certainly seem to know your stuff!

Can I ask what resistor I should use to reduce Arduino 5v to 1.5-2.0v to power the emmitter?
138  Forum 2005-2010 (read only) / Interfacing / Re: LED light gate on: August 13, 2010, 11:41:26 am
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Why use an LED as a sensor when there are devices designed for this purpose?

I was thinking that I only need something cheap and basic, something that will work with a fixed light source and stable ambient conditions, and I am not familiar with other solutions.

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You are looking for something called a "phototransistor" or "photodiode".

Thanks. Do you have any models that you would recommend?

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...without scaling using an op amp you will probably not like it.

Forgive my ignorance, but what is an op amp?

Thank you.
139  Forum 2005-2010 (read only) / Interfacing / LED light gate on: August 12, 2010, 04:21:41 pm
Hello all!

I am thinking about using the LED-as-light-sensor trick to create a through-beam gate similar to what is done commercially with lasers.

I propose to have two LEDs, one as a light source (emitter) and the other as a sensor (receiver). Each LED would be shaded with a small metal tube to inhibit interference from ambient light. The inside of the tube around the emitter would be polished to increase light concentration; the tube around the receiver would be buffed inside to prevent light entering the sensor LED sideways.

The Arduino would only need to detect three different light levels i.e. fully blocked beam, partially blocked beam (for a predetermined translucent object), and fully open beam.

I would appreciate any thoughts on this.

Thank you.
140  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: December 13, 2010, 03:11:07 am
Whitman's Mother Goose App

http://itunes.apple.com/us/app/whitmans-mother-goose/id399672376?mt=8

It got me some brownie points and free time!  smiley-grin
141  Forum 2005-2010 (read only) / Bar Sport / Re: Your last purchase? on: November 22, 2010, 02:06:26 am
PA-15-2-45 high-speed tubular linear actuator. I'll use it like a big solenoid.
142  Forum 2005-2010 (read only) / Bar Sport / Re: I Need A Touchscreen LCD on: December 18, 2010, 09:41:50 pm
You could try an iPad, you can talk to it with the dock connector.
143  Forum 2005-2010 (read only) / Bar Sport / Re: SSR on Ebay on: December 16, 2010, 08:15:43 pm
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But the 0.1% of us wanting to do phase-angle dimming need the kind WITHOUT the zero-crossing circuitry.

Is this what you are looking for?:

http://www.alliedelec.com/search/productdetail.aspx?SKU=6820149

I am interested in making a phase-angle controller for a split-phase motor, so I would like to know more about this.
144  Forum 2005-2010 (read only) / Bar Sport / Re: I Need Aluminum Bars on: December 13, 2010, 08:53:06 pm
http://www.mcmaster.com/#aluminum/=a4wwpv
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