[TriEmbed] Raspberry Pi & Detection Sensor

[Jeff Highsmith]

Brian,

You might take a look at these i2c light sensors from Adafruit:
https://www.adafruit.com/products/439

Having built-in i2c means you won't need to worry about using separate analog to digital converters – the RPi can talk directly to the sensors. The fact that they sense visible light has some disadvantages such as calibrating for ambient light and making sure people's shadows or other light sources don't interfere. For your purpose, though, I like the idea of using visible light because it will make for a better demo of what's happening. You could use low-power lasers or other narrow beams of light, and point them across the "sorting" area, with the sensors on the other side. When the passing objects block the lasers or light beams, the students will be able to see the light hitting the object and not the sensor. That would be cool.

Jeff :)


On Oct 7, 2013, at 13:51 , Grawburg wrote:

> I'm working on a project to demonstrate how a basic conveyor system can separate
> different size objects by using some HO train cars and electric turn-out switches.
> 
> The intention is to have a detector, either a visible light photocell arrangment using
> LEDs or an infrared LED emitter/receiver.  The turn-out switch will be isolated from
> the Pi with a relay.
> 
> I know the photocell will give me a basic ON-OFF (high-low), but what does the IR
> LED give?  I will have a timer loop in my Python code that instructs the switch to remain
> in the diverted position for x-seconds and then return to the default position.
> 
> 
> Brian Grawburg
> Wilson
> 
> 
> 
> 
> 
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