Build Your Own Arduino

Step 2 Setting Up Power

The first thing you need to do is set up power. With your breadboard and components in front of you... let's get started!

 

With this step, you will be setting the breadboard Arduino up for constant +5Volts power using a 7805 voltage regulator.

 

Figure 1-2: Power setup with LED indicator.

 

In order for the voltage regulator to work, you need to provide more than 5V power. A typical 9V battery with a snap connector would work just fine for this.

 

Power is going to come into the breadboard where you see the red and black + and – squares. Then add one of the 10uF capacitors. The longer leg is the Anode (Positive) and the shorter leg is the Cathode (Negative). Most capacitors are also marked with a stripe down the negative side.

 

Across the empty space on the breadboard (the channel) you will need to place two hook-up wires for positive (red) and ground (black) to jump power from one side of the breadboard to the other.

Now add the 7805 voltage regulator. The 7805 has three legs. If you are looking at it from the front, the left leg is for voltage in (Vin) the middle leg is for ground (GND) and the third leg is for voltage out (Vout). Make sure the left leg is lined up with your positive power in, and the second pin to ground. 

Coming out of the voltage regulator and going to the power rail on the side of the breadboard you need to add a GND wire to the ground rail and then the Vout wire (3^rd leg of the voltage regulator) to the positive rail. Add the second 10uF capacitor to the power rail. Paying attention to the Positive and Negative sides.

It’s a good idea to include an LED status indicator which can be used for troubleshooting. To do this you need to connect the right side power rail with the left power rail. Add positive to positive and negative to negative wires at the bottom of your breadboard.

 

Figure 1-3: Left and Right Power Rail Connections.

 

Having power on the left and right power rail will also help to keep your breadboard organized when providing power to the various components.

 

Figure 1-4: For the LED status indicator, connect a 220& resistor (colored as: red, red, brown) from power to the anode of the LED (positive side, longer leg) and then a GND wire to the cathode side.

 

Congratulations, now your breadboard is set up for +5V power. You can move onto the next step in the circuit design.