Introduction: LED VU Meter
Here is the data sheet for the chip from Texas Instruments.
The video is a quick demo that the circuit does work. Pretty nice for my first circuit board!
Step 1: What You Will Need:
Check the schematic and x 2 if you want stereo. You may consider adding a headphones jack, battery holder, voltage regulator if you plan on tapping power from something else, a case to house the final project, etc just depending on how far you want to go with this. If you look at my first project I installed two similar kits into a vintage boom box.
Step 2: Putting It All Together
Certain components like the light emitting diodes only work if you put them in the right direction. When you look closely inside the diode you will see that it is divided. The smaller part is the "+" side and the larger is the "-" side. If you solder these in backwards they won't work.
Make sure you read up on how to solder components to a circuit board. And then practice. This is my first major soldering project so this is my practice. Many things I could have done better (i.e. the LEDs are not soldered at perfectly the same height and I could have spaced them better on the board).
The main thing is to carefully plan the layout of your board and consider you final application. That is why I built the circuit many times over on the bread board before committing to something permanent.
Step 3: Progression
Knowing that I was going to make a left channel display I knew I would have to attach wires to cross over from right to left. If you don't want to solder all those wires on the board you can solder the chip on the opposite side of the board. But not me, I wanted my components on one side, besides, I need the practice. You can see by the pictures I get a bit better as I go. The tricky part was figuring out how to connect between two wire posts . . . the better I got at applying the flux and the quicker I could apply just the right amount of solder the better result. The headphones jack I could have drilled holes to match the posts but I opted to add wire extensions to the posts because I thought that additional hole might weaken the board (It seems I had already drill some holes right down the middle for a previous unfinished project).
Step 4: Almost Done
Well, done for now. I hope I left enough room for the right channel (If I ever get back around to it). The right channel should assemble much quicker because I don't need all the wires crossing over. The IC chip will go right next to the diodes.
As you can see there is a red wire sticking up next to the headphone jack. "Red" is for "Right" of course. The switch comes off of the "-" power line just because it seemed a common point between the two circuits which meet a the headphone jack.
What amazed me about this project is how versatile you can be when you aren't working on a pre-printed board; that really made me feel all the more creative.
Hmm, looking at how my LEDs get shorter as they go from red to green I imagine they will get longer on the other side as they go from green to red.
Hmm, where am I going to put that pesky 2.2uF 25V 105C Radial Electrolytic Capacitor?