Photoresistor

We are going to have photoresistors embedded in blocks that are wedged inside of wood panels on the bench, so I ran a test today on the photoresistor to make sure it worked.

The photo resistor is a relatively simple set up. The secret is to always detect for variance, and not to depend upon any specific light reading. I will have to have arduino run a series of callibrations when it starts, and then do it over the course of the day to account for fluxuations.

I will also have to have what I will call the ASS ALGORITHM. This is a proprietary algorithm to determine if there is an ass on the bench, or if it is just a poorly performing sensor. This will necessitate determining the range of asses out there. Such is work.

For a good and simple arduino example of photoresistor - check this out. Just remember that if you aren't using Arduino to power the photoresistor you have to connect your grounds.
http://www.arduino.cc/playground/Learning/PhotoResistor

xbee working

Thanks to this tutorial:
http://arduino.cc/en/Guide/ArduinoXbeeShield

Using the Arduino XBee Shields were easier than I thought. I set up wireless dual channel communication through a wall - approx. 90 feet apart.

It looks like the XBee are programmed out of box to receive all communications, and that one must program them to receive on a particular channel. Since the communication structures for this will not be very difficult, and I'll be writing my own protocol - that should suffice.

Now to buy that third Xbee and see if I can get all 3 chatting together!

Metal Detector with Arduino

I have hacked the metal detector to be able to have arduino receive and respond to any metal.

Using a $50 Bounty Hunter metal detector, I am took off the backing, and connect to the input and output on the VU meter. I then run this through a voltage divider, and send the output to the Arduino Analog In.

Being very new (noob) to electrical engineering, one aspect that caught me up is that I must connect the ground of the arduino to the ground of the power source (VU meter on the metal detector.) See the below image for circuitry.



Arduino is doing a great job notifying me of how much metal has passed by. Now to find some gold.

Multiplexer part deux

Today I attempted to hook the 4051 BE up with the arduino. I was a bit confused by how I should run ground since it appears, according to the tutorials I have found pins 6,7, & 8 all are connected to ground.

Currently, I can get voltage to surge when I connect power to an input, but it appears across some of the proximate inputs, rather than on a specific point. I obviously need a clean input since I will be using this with photoresistors.