Build a Drawdio, make music with drawings!
Tutorials
Written by Anna Hegedus   
Sunday, 24 May 2009 16:07

Hello everyone, and welcome to my latest love...Adafruit industries!

 

Adafruit's site

 

Adafruit is a company ran by a very clever group of people in New York City.  They sell open-source electronic kits for interesting toys, robots, creative gear, and educational materials.  In particular, one kit, the Drawdio, is very interesting.  It's essentially a pencil that allows you to draw with music.  While it sounds really simplistic, it's insanely fun.  The original creator of the device, Jay Silver, created the original out of a cheap toy he bought in Bangalore, India.  The original video of this can be seen here, where happy children hurry around with the device, trying it on everything in sight:

 


 
 
Doesn't that look fun?  
 
So apparently, Mr. Silver, in collaboration with Adafruit, came up with a kit that is both easy to put together and ridiculously fun to use.  In the following few steps, I'll show you roughly how to put it together!
 
The first thing to do is order your parts.
 
  1. Adafruit's kit
  2. Extra metal tape (can also be found at a craft store...any place that has stained glass supplies)

The second step to this is waiting for everything to come in the mail.  Once that long and arduous process is over however, you can bust everything out and get ready for fun!  You can follow me below, or go to Adafruit's web site for the original kit's instructions.

The kit comes in a shiny metal anti-static bag with a zip lock at the top.  Unzip the bag and carefully remove the components on a bright, well-lit table.

The parts will look something like this:

 

Kit parts

 

 

In that picture, you'll see the following:

  1. A little circuit board (Upper left, in my handy-stand)
  2. A timer chip (Mine was a TLC 551)
  3. A thumbtack
  4. A AAA Battery holder
  5. An on/off switch
  6. A cable tie
  7. A short piece of wire
  8. A long piece of wire
  9. A Pencil
  10. Some copper tape

The electronic parts (Bottom Row)

  1. 680pF ceramic capacitor (Marked 681)
  2. 0.1uF ceramic capacitor (Marked 104)
  3. A NPN transistor (Emitter, Base, Collector).  Mine was a PN2222.
  4. A PNP transistor (Emitter, Base, Collector).  Mine was a PN2907.
  5. (2) capacitors, both are 100uF and 10V
  6. A 1/4W 5% 10K resistor (Brown, Black, Orange, Gold)
  7. A 1/4W 5% 300K resistor (Orange, Black, Yellow, Gold)

Ignore that other resistor at the end...I'll explain it later.

So you warm up your soldering iron and let's get started...

The first thing to do is clamp your circuit board into the helping hands.

 

In the standy

 

 First I soldered in both resistors.

 

Both resistors

 

You'll notice something here which I mentioned above...my resistors look a little different because one of them is.  The one on RA is brown, black and yellow, with the gold band indicating a 5% tolerance.  That's legit.  But the one I am ready to solder in is NOT the one with the kit.  What you see there is orange, red, yellow, with a gold band.  It's a 320K Ohm resistor with 5% tolerance.

If you go to Radioshack and paw through their resistor drawer, you'll find a handy bag of assorted resistors.  It comes with all different sizes, from a 100ohm to a 1 Mega ohm for about $5.  Or you can be like me and tear apart an old radio.

Anyway, the resistor in B is the one that controls the pitch.  According to Jay Silver's post here, the larger the resistor, the lower the pitch.  Since mine is 320 kilo ohm, it will have a slightly lower pitch than a stock Drawdio, but not too much.  Experiment with you new bag of resistors!  Have fun!  Use Solder!  Yay!

Anyway, with that done, I  did the ceramic capacitors and the on/off switch.  The switch and the ceramic caps has no polarity, so you can solder them all in any which way.

 

Capacitors
 

Then I did the timer chip.  This is one of five components on the board that are asymmetrical.  You need to put it in the right way or else it wont work!  Solder it so the little dot on the chip faces the notch on the top of the board.

 

Time chip
 

After the timer chip, I soldered in the two transistors.  These ones have a polarity.   Put them in so the flat edge faces the flat edge of the drawing on the board.  The board is labelled "NPN" and "PNP" where they should go.  The NPN is the one marked 2222 and the one market 2907 is the PNP. 

The electrolytic capacitors are in their sockets on this picture too.  To put those into place, they have to go in the correct way.  There are several ways to tell how a capacitor is oriented:

  1. The longer lead is positive (+)
  2. The negative side has a stripe down the jacket (-)

 Put those in and solder them in C1 and C2.

 

Transistors
 

 
Now I soldered two 4" pieces of wire to the speaker back.  I then soldered those into place on the back of the Drawdio board where SPK+ and SPK - are.

 
speakerspeaker2
 
 
Once the speaker is on, you can test the kit out and use it!  To test it, take the battery holder and thread it through the little holes on the board.  Turn it on, and squeeze both ends of the board where the metal is.  You should hear a squeal like in my video at the bottom of this page.  If you heard it, yay!  If not, check everything over.  LadyAda's original tutorial on building it is here and you could also ask for help on her forums.
If everything worked fine, sharpen the pencil, we're almost done!  Attach the drawdio to the pencil with the cable tie like this and sharpen the pencil:

 
Drawdio on pencil
 

 
Once you get the drawdio on the pencil, take the metal tape and cut a small 1" piece from it.  Take that piece and tape the top of the Drawdio where the metal tab is to the top of the pencil.  Take the larger remaining piece of tape and wrap the base of the pencil.  Push the thumbtack through the top of the copper strip ontop of the Drawdio so that it's contacting the graphite in the pencil.  Your finished product should look like this:

 
Drawdio here

 
 
And now, play!  The Drawdio turns your body into a circuit, so the pencil is one side and the graphite in the pencil is the other.  By drawing a line, you increase the length and resistance of the circuit.  The longer the line drawn, the lower the pitch of the noise.  The shorter the line will make a higher pitch.

 

 

All in all, I have to give the Drawdio an A+.  The kit was wonerfully well put-together, well documented, and well thought out by both Ladyada and Jay Silver.   It's also really fun! I'll definitely be doing more kits with everyone in the future, and you can bet they will be coming from Adafruit!
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Last Updated on Monday, 25 May 2009 14:18