Instructables
This WAS going to be my entry to the 'Get the LED Out contest', but I was too slow.

I was bored one day. I wanted to build something cool. A quick bit of brainstorming and nothing came up. Digging through my junk boxes, I found a old level meter kit. I went over my mate's place later that day and we were having a killfest in Halo 3. He had seen this Level kit in use before, and wanted it rebuilt into a full-blown system to complement his surround system.

Here I'll guide yo on how to make your own.
 
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Step 2: Tools

You will need the following tools:

Drill
Jigsaw
Multimeter
Spray Paint (optional)
Soldering Station
Solder
Wire Cutters

Step 3: Power Supply

PIC_0214_1.JPG
PIC_0215_1.JPG
The kit I used Needed a supply at around 9 - 13 V DC, at up to 250 mA. I had a 12V AC 280mA Plugpack (also called wall-warts) sitting around. But the circuit called for DC. What to do?

The solution was for me to make a simple diode bridge (bridge rectifier). It uses just 4 small power diodes.

I layed them out, soldered them together, added a supply and viola! 15V unloaded. Perfect!

Step 4: Transistors!!!

Now onto the kit. It originally had 3mm LED's but these had to be removed. After that, I examined the circuit. The LED's originally used a common positive and the chip switched the outputs low to light the LED.

This meant I needed a PNP transistor.

Enter the simple but effective BC558. Actually anything will do here. Everyone should have plenty of these in their parts drawers. If not, well, you'll need to go get some. 10, in fact.

After finding them, you'll need to cut their leads into a special shape. Not 100% necessary, but makes life easier.

See pictures for more info.

Bend the collectors to 90° behind them. Slot them into their respective holes and solder them in.
Dr.Bill2 years ago
So where's the schematics ?
nhesterberg3 years ago
Soo a few things

1. What's the potentiometer for?
2. What is the audio input source? Like a regular 3.5mm input jack?
jpodejko3 years ago
Now just to be clear, is this for a power level?
bror893 years ago
hey what's the difference with these two chips? LM3915 IC chip LM3916 IC chip
is it possible to do this with more LEDs?
Da_Fudge (author)  almostkorean6 years ago
yeah, just make sure your transistors can handle it. even better, replace the LED's with relay's. then you can put as many lights as your relay can hold!!! I'l send you a circuit diagram if you want.
if you could send me a circuit diagram that would be AWESOME
Da_Fudge (author)  almostkorean6 years ago
k. I'l P.M you something soon.
If you did make a circuit diagram, would you mind sending one my way too?  I love this idea but really want to make one with a bunch of LEDs per sounds level!  Thanks
Could I Please have a circuit diagram too?
where were you able to pick up the LEDs?
Da_Fudge (author)  Eeeeeeeeeekz5 years ago
i got them from my local jaycar store
Dude, you're freaking awesome! Your stuff is amazing, I really like it, I hope to see more, this one is just really cool. Maybe you should have made the LEDs rainbow colored? No-- even better. RGB. Nice job anyways, I just have 3 more things to say to you. 1) +1 rating. 2) (added to favorites) 3) You should post an Instructable on how to make fudge.
Da_Fudge (author)  GorillazMiko6 years ago
you like it? ok then, be prepared for an onslaught of instructables. Turbocharged go-karts, remote control docks, huge cinema displays, and awesome spud cannons. My aim is to get featured, as it will greatly boost my pageveiws. I'm in a contest against myself. You have been warned!
G'day mate I'm lookin forward to it Great I'ble
Da_Fudge (author)  GorillazMiko6 years ago
thanks.
n0ukf6 years ago
Where's the project schematic? Where's the (BC558 or equivalent) transistors in the parts list? Your instructions in step 4 don't say what side is up when you cut the leads and the pictures are hard to see that the flat side is up when cutting the right 2 leads (base and emitter) short. For anyone substituting transistors, be sure of the pinout, since the 2N3906 has a reversed (EBC) lead order from the BC558 (CBE).
scotty37856 years ago
It would be great to stick one of these in to the case of a pair of speakers behind the mesh that covers the cones. Would look fantastic on a guitar amp too!
Da_Fudge (author)  scotty37856 years ago
yeah. this design is so flexible. once you have built the board, you can mount it anywhere. it is only 80mm x 28mm x 9mm. The led's can be aranged in any order, too, so it doesn't have to be 1 - 10. I have done before 5,8,1,3,7,6,2,9,10,4. it looked really cool.
jolshefsky6 years ago
My favorite bit was the hack to stick a transistor's base-emitter pair into an LED hole, leaving the collector for switching a bigger load.
Da_Fudge (author)  jolshefsky6 years ago
thanks for your comment.