Circuit Bending

  1. Who I am
  1. Involvement with bending
  2. workshops
  1. one on Sunday
  1. parts (dealer)
  1. What is Circuit Bending
  1. Basic overview
  1. Bending is an art of exploration
  2. Quick example
  1. Some history
  1. Reed Ghazala
  1. “father of circuit bending”
  1. holds no claim at being the first
  1. coined the term in the 60’s
  2. Circuit-Bending : Build Your Own Alien Instruments
  1. Handmade Electronic Music: The Art of Hardware Hacking
  1. Common Bends
  1. Most common/easy exploit is timing circuit
  1. Resistor/capacitor analogy
  2. Can be explored with bare hand
  3. Not always present as chip on board has gotten better
  4. Leads to all resistance based modifiers
  1. body contacts
  2. potentiometers
  3. photo resistors
  1. Voltage drain usually works
  1. Newer toys often have brownout protection
  1. Audio out is a keystone
  1. Sometime the signal is a bit hot
  1. not always a problem
  1. Line leveling and volume control can help
  1. Power Switch is important
  1. toys sometimes need to be reset
  2. useful for always-on toys to save batteries
  1. Lighting is a big help for saving power
  1. you see when something is on
  2. looks cool
  1. More advance bends
  1. Patch bays
  1. Useful for very complex toys
  1. Glitch switch/configuration
  1. Not always present
  1. Crash point
  1. Also not always present
  1. Changing out crystal
  1. simple timer circuits work well
  1. Changing out caps
  1. more dramatic timing changes
  2. can also change waveforms
  1. Using LEDs
  1. running sound through them
  2. in series with some circuits it can give a dirty sound
  1. Opto-isolator triggered buttons
  1. useful for non-repeating type toys
  2. used with a micro or timer chip
  1. Midi-controlled toys
  1. Opto-isolators
  2. digital pots
  3. timer control
  1. What to look for in toys
  1. Battery powered!
  1. 3v safe to poke around with bare wires
  2. 4.5v probably safe to poke around with bare wires
  3. 6v+ should use protection
  4. 9v+ definitely use protection!
  1. 9v battery vs 6+ AAs
  1. Furby and the tickle of death
  1. Ones with fun sound samples
  1. Play with it to get an idea of how it works
  1. Does button repeat when held down?
  2. Does button reset with multiple presses?
  1. Often limited to just a few exploits, but can be worth it
  2. Great for sampling, or background noise
  1. Ones with Audio input
  1. Input for mic (usual) or other instruments/toys?
  2. Does it have a built in amp?
  3. Does it have a built in Mic?
  4. Are there effects?
  1. echo, delay, voice modulation, etc.
  2. Barbie Karaoke machine
  3. Voice changer
  1. Age of toy
  1. Mid-nineties to early two thousands are great
  2. older toys with good electronics that still work are rare
  3. In early 00s electronics got cheaper on a smaller scale
  1. means more crap on the market
  1. New toys may be entirely COB with brownout protection
  1. basically means, you can’t do anything with it
  1. Novelty
  1. How likely is it to be seen elsewhere?
  2. Multi-language
  3. Great cases!
  1. No, seriously, how cool is the case?
  1. Creepy toys are the best!
  1. Already existing audio output
  1. Mostly in keyboards and “serious” toys
  2. Buddhist chant boxes
  3. Volume control almost always built in!
  1. Hollowness
  1. How much room is there for things?
  2. Will it need a breakout box?
  3. Will it simply need to be re-cased?
  1. How small/nice/new is the toy?
  1. The smaller the toy, the smaller the parts, and the more delicate soldering you’ll need to do
  2. Almost all new toys use SMD parts
  1. Where to look for toys?
  1. Second hand stores.
  1. Unless your state is stupid like MA
  1. Stooooooopid lead laws
  1. Get to play with the toys beforehand
  1. Flea markets
  1. no telling what you will get
  2. still get to play with toys, but do not always have batteries
  1. bring some with you
  1. MIT-flea is OMG
  1. also bring batteries though
  1. eBay
  1. can usually find ANYTHING
  2. usually cheap enough that buying random toys can pay off
  3. well known bending toys can get expensive
  1. After-holiday sales
  1. Ripe for those WTF toys
  2. December 26th is the best day evar
  1. Big box stores
  1. Great for sales
  2. Target
  1. Yada Yada Yada is a good buy
  1. Tools of the trade
  1. Things for opening things
  1. Screwdrivers, etc
  2. Flat things to pry tabs
  3. patience
  1. Various resistance based things
  1. Various pots
  2. Photo resistors
  3. mixed resistor packs are nice
  1. Alligator clips
  2. Wire
  1. Both solid core and stranded
  1. various sizes of each
  1. 30 gauge Kynar (wire-wrap) wire is great
  1. you’ll need to stress relive it somehow
  1. Soldering iron
  1. importance of tip maintenance
  1. Solder
  1. the leaded kind
  1. tastes delicious!
  1. don’t actually taste it!
  1. Drill or drill press
  1. Dremel is perfect, with an 1/8” bit
  1. Multimeter
  2. Tapered Hand Reamer
  1. Best
  2. Tool
  3. Ever
  1. patience
  1. bending is an art, and can take significant amounts of time
  1. Beer
  1. no, this is really a tool, you’ll see
  1. Tolerant roommates / significant others
  1. An into to basic bending
  1. Play with your toy
  1. This has been stressed already, but do it
  2. How does the toy respond?
  3. Does it make sounds you like?
  4. Do all the buttons work?
  5. Can you get it to crash regardless of bending?
  1. Speak and Spell
  1. Open up and explore the toy
  1. Use your hands first
  1. re-stating to not use wall-powered toys
  2. lightly moisten
  1. See, that beer IS a tool! Condensation FTW!
  1. look for resistors first
  2. give it the bad touch
  1. can you show me on this Furby where the bad man touched you?
  1. take notes along the way
  2. I like to solder a little bit of wire to interesting points
  1. add leaded solder to the lead-free stuff on the board
  1. re-stress voltage issues
  1. explore with some kind of resistance in place
  1. use alligator clips with a 1M linear pot to poke around
  1. keep reducing by 1/2
  2. try other linear pots as well
  1. 500k, 100k, 10k, 1k
  1. try photo resistors
  2. touch the clips to see if it gives further control or changes
  1. Tie pins to ground with pot in series
  2. Try random pins with pot in series, gradually stepping down
  1. Toys with motors, especially true
  1. just because it stops making sounds doesn’t mean it is dead
  1. pull out the batteries
  2. make sure the circuit is still completed
  3. reset switch can be important!
  1. tie random things to ground (with pot in series)
  2. Tune you points and take notes
  1. Circuits need to be complete to make sound
  2. Keep reducing resistance till it stops working
  1. did the toy start crashing at any point?
  1. disconnect the pot and measure the resistance
  2. measure the original resistor (if you want to keep the same sound as an         option), and then take it out
  3. explore the circuit with that resistor now gone
  4. decide resistance controls based on behavior
  1. pots are good for huge voltage changes, or for specific control
  2. photo resistors are fun, but harder to control
  1. you’ll need to tune the circuit, or find a LDR that works with         your circuit
  2. does not always work out
  1. touch contacts are fun and easier to learn
  1. can generally tune them
  2. provides cross-contamination for various parts of the circuit
  3. a must for complex bends, as it adds many levels of control
  1. if you want the toy to start in any condition, then you’ll need to put a resistor in series with whatever you do
  2. pick a pot based off of where the controls get less interesting
  1. a big pot has big changes, hard to hit sweet spots
  2. smaller pots can miss out on the full range of sounds
  3. either find a balance of control, or use two + pots
  1. Audio out is important!
  1. For low voltage circuits, easy to just tie to the speaker
  1. measure with the multimeter to determine polarity if not marked
  1. not important for most things, but very important if you want to connect your toys together
  1. The speaker will sometimes act as a mic if you do it this way though
  1. It’s easy to just use an audio 10k pot to give yourself both volume control and a voltage divider for sound output
  2. Cutoff jacks can be useful.
  1. Audio input is great, if the circuit handles it
  1. If the toy has a jack, you are good to go
  2. if it uses a pre-amp, even better
  1. instant effects pedal
  1. try adding input across the mic pins
  1. may want a cut-off jack here as well
  1. You’ll want to just tie the ground to ground directly
  2. just play around till it works
  1. you may need to put in a small voltage divider to lower input if the pre-amp is too sensitive
  1. An intro into advanced bending
  1. If you find tons of interesting points, create a patch bay
  1. touch/patch bays are easy to make with RCA jacks
  1. explore with various caps
  1. be careful of the big ones!
  2. look for the tiny ceramic ones first
  1. explore with LEDs or other diodes connected to various points
  2. Video bending
  1. for toys that hook up to the TV
  2. make sure that it doesn’t plug into the wall!
  3. explore as usual, but check out both the audio and video
  1. using timers to trigger buttons
  1. sometimes you can get away with a simple transistor that reads the speaker, but not always
  1. Midi input
  1. Arduino midi library
  2. opto-isolators for button presses
  3. digital pots for resistance changes
  4. square-wave output for timing circuits in the toys
  1. keeps the toy on beat
  1. Great resources on the web
  1. Casper Electronics
  2. Get-Lo-Fi
  3. Bentfestival
  4. Me
  1. I’ve got parts
  1. Workshop plug
  1. $25 includes an easy button and access to my part bins
  1. my part bins are not a joke!
  1. $20 if you have the easy button
  2. fills up when there are no more easy buttons, as I’ve got tooooons of parts
  1. Questions?