Fun with Hex Schmitt Triggers

Recently I've been playing around with some of the oscillator projects outlined in Nicolas Collins' excellent "Handmade Electronic Music", a must-read for anyone interested in home-grown audio. This finished project is constructed around a single Hex Schmitt Trigger integrated circuit that is wired to oscillate at three different rates, resulting in a nice droning cacophony. Two of the oscillators are controlled by photoresistors, and the third is regulated by a 50k potentiometer. A second 10k potentiometer is wired to the positive line from the battery (creating a variable power starve), and also to the output line of one of the photoresistors - dunno why, but it seems to add that extra little something something.

Here's what the final breadboarded circuit looks like:


Sounds good - now it's just a matter of transferring it from the breadboard to a regular circuit board, and finding a box to house it.

Interior of completed Drone Box. The battery is held in place with velcro.

The two small holes at the center are for the photoresistors, which are held in place by plastic soda straws.

Then I put together a second Hex Schmitt Trigger oscillator, the output of which is connected to a single LED. The LED blinks at a variable rate controlled by two potentiometers.

Next I inserted an LED into one of the photoresistor holes in the Drone Box. The LED was then attached to the second oscillator output with clip leads and held in place with electrical tape.




So, what does it sound like? The first video below shows the Drone Box with the pitch of the photoresistors manipulated by a flashlight. The second video shows the box with the oscillation regulated by the blinking LED.

Found Friday 62

"Dogs say we did it. I guess they did."
(32 fox, Michigan, 1948.)

Found Friday 61

Vermont, c.1960.

Vermont, c.1960.

Found Friday 60

My finest day is yet unknown
(found on the street, Savannah, GA. 1996)

Found Friday 59

Found Friday 58 - A Chapter on Symmetry

Glamis Castle, Scotland. 1973

Scotland. 1966

Found Friday 57

Lake Manyara Hotel, Tanzania, 1969

Scotland, 1961

Found Friday 56 - Happy Halloween

colonial fireplace, c.1950's

Found Friday 55

Longleat Safari Park, 1970

Found Friday 54 - New York, August 1973

Found Friday 53

photograph, early 1900's

Found Friday 52

Headline and illustration from the Saturday Telegram, Manchester, NH, August 20, 1892

Found Friday 51

A Barrel of Fun at Put-in-Bay, Ohio. 1923. postcard.

Some historic photos of Put-in-Bay, c.1900.
The Beer Barrel Saloon, home to the world's longest bar (and some truly terrible-looking cover bands), Put-in-Bay, Ohio.

Found Friday 50

Fatima Procession, Portugal c.1973

Found Friday 49

cyanotype postcard c.1920's

Found Friday 48

Fire, Hamburger Stand, Springdale, Utah c.1940's

On this day in 1666 the Royal Exchange burns down in the Great Fire of London

Found Friday 47

"Rich / Highly Educated / Poor"
detail, scrapbook page

Found Friday 46 - Say Cheese

A la fromagerie, Roquefort-sur-Soulzon
(Societe Anonyme des Caves et des Producteurs Reunis de Roquefort)

More French cheese:

Circuit Bent Sing-A-Long Barbie Karaoke Tape Recorder

My plans for a productive 3-day weekend devoted solely to art-making were dashed by some charitable person who donated a Barbie Karaoke tape recorder to the local Goodwill. Not too long ago I read about circuit bending one of these on Peter Edwards fantastic Casper Electronics site, and I've been on the lookout for one ever since. After buying a stack of fresh batteries and looking over the bending schematics I started poking around the main circuit board and identified a bunch of bend points, mostly around the echo circuit. The Barbie Karaoke has a cheap "echo" feature that when bent creates strange and wonderful noise which are generated once you turn the tape player on. After finding about 20 different bend points I decided to build a separate panel on which to mount the the various components, similar to what I did with the Caisotone. The Karaoke machine would be attached to the top of the panel with the wiring running through holes drilled in the bottom, then soldered to the various components inside the panel. Each wire attached to a bend point on the circuit board was soldered to one of twenty banana jacks, which can then be connected by lead wires to a series of potentiometers. I also added a pitch adjustment (located towards the back of the panel, on the left) and both an input and output jack - another cool thing about the Barbie Karaoke is it has two input lines (one for an audio source like a CD player, and the other for a microphone) so you can plug other stuff into it, such as other Barbie Karaokes.

Some photos:

Partially wired panel with banana jacks, switches, and potentiometers.
Each pot can be turn on & off with it's own switch.

View of circuit board back in place with bend points all soldered up & wires fed through holes drilled in the bottom of the karaoke. The bundled wires at the top of the photo are all soldered to points on the echo chip.

View of bottom of completed panel.
The Barbie Karaoke is attached to the top of the panel with a single screw.

Finished!

Finished view with lead wires plugged into various bend points.

I'm really pleased with how this piece turned out. There are a few other mods you can do, such as adding a variable speed controller for the tape player that involves replacing some circuitry - maybe next time. For now I'm happy to experiment with this as-is:

Circuit Bent Elmo's World Talking Cell Phone

So my latest weekend project was circuit bending a Fisher-Price Elmo's World Talking Cell Phone that I picked up for 49 cents at our local Goodwill last Friday. After taking it apart and locating the up/down pitch bends I decided to re-house the components in a new box - there just wasn't room for the various switches & potentiometers in the original toy cell phone body. I found an old translucent plastic VHS tape box that was just the right size to hold all the guts, and got out the Dremel and soldering iron and went to work. I added two 1M pots for the pitch bends, and added 2 toggle switches - one for the distortion bend, and another to trigger the audio clips that would've played when you opened the original toy phone. I mounted the keypad directly to the inside front of the box and drilled 1/4" holes for each touch point on the keypad. I also added a 1/4" audio output jack so I can play it through an exterior amp, f/x pedals, etc.

Overall, I'm really pleased with how this one turned out. Although it's pretty basic, the distortion bend makes it into something obnoxiously special (see video clip at bottom).

front view w/ pitch bends identified

back view

finished box, front view

finished box, back view

finished box, open view

Found Friday 45

Hawaii, c.1945

Test Pattern (return to square one)

So after nearly a year of electronic detritus, white noise, and cigar box guitar-building I've circled back to the Test Pattern paintings. My goal is to work on these exclusively over the next couple of months. Anyway, here's the first new one. I did the 4 x 4" study for this one last August and looking at it again last week I felt it still held up. The dimensions for the different elements were transcribed to an 8 x 8 x 1-3/8" panel, then the newly-painted/collaged elements were attached (more about the process here.) Comparing the study to the finished piece you'll notice that I goofed up the dimensions in the upper right corner. It's okay - after a bit of angst & recalculation I think I'm happy with how it turned out.

Test Pattern - Desert Fox (study). 2009.
collage, gesso, gouache, enamel, and pastel on paper. 4 x 4"


photo of study with transcribed panel


Test Pattern - Desert Fox. 2010.
acrylic, collage, pastel, gesso, and gouache on panel.
8 x 8 x 1-3/8"