So today I sat down and slapped together what I am referring to as a "volume board." Really, there is no sound involved with this project yet, so it's not much of a volume board. However, what the project does do is display a very simple digital output based on an analog input signal, or, an electrical "volume." Hence the name.
I put together this project because I needed some practice in dealing with analog signals as inputs to my microcontrollers. Hence, I did some browsing on LadyAda.net and Sheepdog Guides and found this and this tutorial respectively. Both of these guides discuss safe ways of hooking LEDs up to Arduino's 5V power output pin. They also touch on the Analog input pins. The Sheepdog tutorial gave me the idea to use a potentiometer to control an analog signal to my Arduino board in order to light up certain LEDs. Thus, I mostly ripped off that design and modified it for my own purposes. Since my primary goal was to learn about Arduino analog signals, I did not feel it necessary to design an entire concept by myself. So, without further ado, I'll explain a bit more about what I did and how I did it.
Setting up my LEDs
the positive lead of the LED are on alternate
rows. This connects the components
without shorting themselves along the row.
Once I had all ten LEDs lined up in the manner described above (depicted in Figure 2), I was ready to begin testing each LED. Remember that lesson I learned about testing circuits early on in my Symet project? Well this is where that lesson kicked in. I took a hot lead from the 5V output pin on the Arduino board and plugged it into each row that had only 1 resistor leg stuck in it. This established a circuit between the 5 V pin and the GND path that went through the resistor and LED. It is important to keep the resistor in sequence with the LED because the LED could burn out if hooked up backwards. The 1k resistor helps dissipate some of the energy in the circuit and prevents this from happening, even if the LED is hooked up backwards.
I should note that I activated the Arduino board with a simple 9V battery hooked to the Vin and GND pins of the Arduino board. With this configuration, each LED should have lit as I touched the 5V lead to each LED's respective resistor. This process is depicted below in Video 1.