Instructables
Picture of NoiseAxe MiniSynth
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This Project is Mini Synthesizer, using a PICaxe. It was designed by Brian McNamara. If you're looking for a mini drum machine, you should check out his other project, The GrooveAxe. His other project is the MemAxe

You can get the kit from Gadget Gangster & grab the schematic. here. The kit comes pre-programmed. But, if you'd like to gather the parts yourself, you'll need the following.

Parts list

  • Resistors, 1 each of : 1k, 3.3k, 330, 560, 100k, 2.2k, 220k
  • 4 x 10k Resistors
  • Gadget Gangster project board (half board)
  • 10 uF Cap
  • 8 Pin Dip Socket
  • 3xAA battery holder (and batteries)
  • 10k Photoresistor
  • Micro Speaker
  • 22Ga Hookup wire
  • And a programmed PICaxe 08M. You can get the Source Code off Gadget Gangster
You'll also need a soldering iron, solder, and wire cutters.

Here's a little video demonstration


How to Play It

The NoiseAxe will play 8 different notes, each note is played by touching one of the 8 resistor legs at the bottom right of the PCB with the stylus wire. You can change the level of modulation by varying the light that enters the photoresistor, creating a vibrato effect. This is done by putting your finger over, or shining a small LED torch onto, the photoresistor.

How it Works

The NoiseAxe is based around the Picaxe 08M micro-controller. The 8 different notes that it will play are controlled via a stylus that you use to touch each of the 8 resistors legs at the bottom right of the PCB. Each resistor makes a voltage divider that produces a different voltage when that resistor is touched. The voltage is sensed by the ADC (analog to digital converter) on the Picaxe and converted into one of 8 values in the program. The 8 note output corresponds to one octave on a keyboard. The sound command is then used to output the correct note to the speaker. The photoresistor is also used in a voltage divider circuit connected to one of the inputs the micro-controllers ADC. A digital value is read within the program and added or subtracted from the frequency sent to the sound command.
 
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Step 2: Wire Links

Solder the wire links to the top side of the board at coordinates:
-E2 to Q2
-L4 to Q4
-A4 to F4
-D6 to F6
-D10 to E10

Step 3: Resistors

Place the resistors on the top of the PCB at the following coordinates:
- R1; A12 to L12 330R
- R2; A13 to L13 560R
- R3; A14 to L14 1K
- R4; A15 to L15 2.2K
- R5; A16 to L16 3.3K
- R6; A17 to L17 10K
- R7; A18 to L18 100K
- R8; A19 to L19 220K
- R9; L6 to Q6 10K
- R10; E5 to F5 10K
- R11; C6 to C10 10K

Step 8: Speaker

Picture of Speaker
Cut 2 pieces of wire about 2 long, strip both ends and solder one end of each wire to each terminal of the speaker. Solder the two wires to K8 and Q8 on the top side of the PCB.

Bend the wires to place the speaker in the place were you want it.

Step 9: Fit Picaxe

Picture of Fit Picaxe
Fit the Picaxe 08M to the 8pin IC socket on the PCB.

Step 10: Fit Batteries and Test

Picture of Fit Batteries and Test
Fit the 3AA size batteries to the battery box. Turn the NoiseAxe on and check for sound by placing the stylus on each of the 8 resistor legs that terminate in row L.

That's it! To grab the schematic, source code or to order a kit, check out the project on Gadget Gangster.
Coolkid41 year ago
Check out Tic Tac Tunes, another picaxe powered mini music maker
StJohn3 years ago
Please do not laugh, I am a quilt artist. I am working with conductive threads to eluminate specific section of my quilts. However there is a very big problem
I need a continuious sourse of power when the quilt is being exhibited. I am not an electronic person. I need help.
I would like to have a sourse of power that is very light and it can be sewn on the back of the quilt and be a power source to eluminate the conductive threads. With an on and off switch. If these power sources could be light enough so that more then one can be incorporate , because the quilts are very large. If you have any ideas I would be gratefull.
Thank you for your time and energy. Maria E. Cosimano-Kohl
this is weird. did any one notice how much this noise axe is like Make zine's pic axe?
Gadget Gangster (author)  guitarmonk154 years ago
I would suspect it would pretty similar as they were both designed by Brian McNamara. He also did the GrooveAxe, another PICaxe 8-bit mini synth.
Unit0424 years ago
I don't see a schematic...!
Gadget Gangster (author)  Unit0424 years ago
Check the word doc on the project page in the resources section.
Many appreciation(s)!
timnolan4 years ago
neat project. you just need a feedback loop and some pots to make a square wave synth though
thepelton5 years ago
Thanks, that was cute, but needs recogizeable tones and volume before it could be considered a proper musical instrument. Nice start, though.
I disagree. It can't play Beethoven's 5th but neither can a snare drum. Both instruments are musical as heck, though. :)
All right. I concede. I suppose if you want compact size, you have make some concessions. I discovered a long time ago that there are tones you just can't get out of a harmonica.
Gadget Gangster (author)  thepelton5 years ago
You might find Brian's other project, The GrooveAxe, a little more up your alley.
Kiteman5 years ago
It's a teeny Stylophone!
Gjdj35 years ago
That's sweet! I don't if it was this, or a similar project that was featured in Make: recently, but I like it.
Brennn105 years ago
Great step by step instructions! For many, PCBs can be hard to master and providing the details really helps everyone out!
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