I'm a software guy and am dabbling a bit with arduino recently. I don't understand many things when it comes to taking a circuit board schematic and doing it in real life.

For instance, at this tutorial: http://blog.makezine.com/projects/make-34/the-dryer-messenger/, I don't understand what to do with this: (that is how I build out the circuits that he's describing in these bullets or in the schematic attached to the post.)

  • Since the dryer runs on AC, current flows in both directions, causing the voltage to swing positive and negative. The Arduino can only sample positive voltages, so I used a voltage divider to bias the sensor’s output. The volt- age divider uses two 10K resistors (R1 and R2) to obtain 1.65V from the 3.3V supply.
  • The current sensor has a fairly linear output up to 1V at 30A, which means the Arduino will read 0.65V or 2.65V when the sensor sees 30A. Capacitor C1 goes between the sensor and the Arduino to filter out noise.

I would really appreciate a simpler schematic and some understanding of what's going on.

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    \$\begingroup\$ I don't think you're going to be able to simplify that schematic much. it's pretty much as minimal as it gets already. \$\endgroup\$ Jun 12 '13 at 20:52
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    \$\begingroup\$ Can you give us a bit more about your background/experience with an Arduino? You seem to be in a bit over your head, but it's hard to say by how much. If you're real inexperienced, I'd recommend starting with a "Hello World" type exercise, and make the arduino blink an LED. Then, move up a hair, and use a potentiometer to turn the LED on and off by comparing to a minimum value. Then use the pot to adjust the intensity of the LED. After that series of exercises, you'll be ready for this project (after looking up "half wave rectifier" to deal with your current sensor!) \$\endgroup\$ Jun 12 '13 at 23:07
  • \$\begingroup\$ Thanks for the help everyone. I was just lost on the fact that I would be connecting another lead off of a resistor to resistor junction. I found this site to be helpful as well: allaboutcircuits.com/vol_6/chpt_3/4.html \$\endgroup\$
    – sam
    Jun 13 '13 at 14:27

Although technically you could use the text to build the circuit, the purpose of the text is really to explain why the circuit was designed that way, and how it works. You can build it just fine using only the schematic.

Look at the schematic and just focus on one component, say R1, and follow the wires attached to both ends. One end is attached to 3.3V, so connect one end of your resistor to 3.3V. The other end of R1 attaches to R2, C1, and pin 2 of the sensor jack, so find a good place on your protoboard to connect those four components together. The other ends of R2 and C1 get attached to ground. Some capacitors have polarity markings on them. Make sure the negative end is the one attached to ground.


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