Grove I2C Touch Sensor Midi keyboard
Create a Midi keyboard with 4 buttons with the Seedstudio Grove Kit touch sensor.
- It uses the USB MIDI Library with an Arduino Leonardo,
- the Arduino USB interface can be used directly as an MIDI Interface
Repository and Files: https://github.com/Sonicrobots/Capacitive-Touch-Midi-Keyboard/blob/master/main.ino
Sculpturist and welding expert [Kolja Kugler] builds robots and robotic installations for years already. His pneumatic robotic band is a smashed together explosion of steam punk like mechanics and music instruments.
We wanted to create light effect: short fades of 10W Leds which can be put on stage and are triggered via MIDI.
- 8 Channels
- Up to 10W LEDs at 12V per channel
- One LED Driver CAT 4101 per channel
- PWM Dimming of the brightness via Midi
- MIDI-IN and through
We used a dedicated LED Driver for each channel. Its the CAT 4101 which can drive up to 1A. A TLC5940 creates the PWM Signal. Up to 16 PWM Channels from the TLC (here we use only 8) are controlled via SPI from an ATMEGA168. Like this the load of the ATMEGA is kept low when a lot of dimming is performed. Midi-In is straight forward through an Optocoppler.
The MIDI Channel can be set with an hex coded 16 stage switch.
Our sketch contains a programm for fast dimming of the LEDs. Like this an LED will flash and slowly decay, which is a cool effect together with sound. You can see an example here (with 3W LEDs):
You can of course write your own sketch using ours. A good start is the example in the TLC5940 Arduino Library.
You don’t own a haunted castle but still want that Scottish chic of a “ghost chateau”? Make your own ancestors portray with automatic moving eyes and easily scare away unwanted guests!
We all know that old movies, where the young couple is staying in the haunted castle for the first night and gets scared away by pictures of some beardy ancestors, where the eyes seem to follow the spectators. In the end its just the butler who is spying from behind to get the heritage … but anyway. So you want to build one of these pictures, too. It’s not hard!
Before you start
- Time: 6-8h building time + time for the stuff you order online to arrive (days!)
- Level: Mid. A little programming, soldering and general handcrafting skills required
- You need: standard Tools (cutter, drill, screw driver),
- Arduino Uno,
- Standard Servo Motors from Futuba or Hitec e.g. this
- Hot Glue,
- Frames with old pictures (see below),
First you need a picture of your loved (or hated) one. A good portray in a high resolution (> 2MB in size) is recommended. Some photoshop magic later you have the picture with a custom background you find in the Internet. Put it into an online oil painting generator to create an even more old school look.
Now you need one or two framed pictures from the flee market.
Cut away the original background – maybe you can reuse it if its hard wooden sheet. In other cases cut some fresh wooden sheet of 2-5mm thickness.
Measure the frame and rezise the digital portray accordingly. We printed the photos out on A1, 230g/cm linen structure paper as a digital print (in europe yuo can use flyeralarm).
When the prints come from the printing service you can start making! We reused the background from the original frame picture we got from the flee market, but you can use any type of (wodden) material thats fits in the frame. We recommend a thickness of 2-6mm.
Now its time to cut the shape of the print as well as the eyeballs of your loved or hated on. A wonderful job, plus you have spare eyeballs now!
Now mark on the wooden background where the eyes are sitting. Now you need eyes. Its not so easy to get decent eyeballs in the Internet (we haven’t checked the dark web though), so you are very lucky, because we prepared some for you! You can find a print ready A4-pdf with fitting eyeballs here. Adjust the size when you have a bigger / smaller image and print them out on A4.
Take your background wood and mark where eyes will go. Measure it with the eyeballs you arleady have. Cut out a square as in the picture below.
Glue the eyes to the remaining wood you just cut out (which you made a little smaller on both small sides so it can move!)
We had a 3D-printer so we could print a holder. You can find the STL files in the github repo below. If you don’t have acess to a printer or use another type, we recommend building something similar from wood. The following steps are how we did it with our setup. It will probably differ if you want to rebuild this. Use your imagination and handcrafting skills to replicated the functions.
On the eyes-sqaure we used an holder (the black one) and a terminal thread to hold the acrylic thread and a rubber band.
The moving eye-square is on the one side connected to the moving servo motor. The other side is fixed with a rubber band, so it gets drawn back if the servo releases. Be sure to put some wood over the backside so the eyes can still move, but also don’t fall out to the back!
Now, wire and program the arduino with the code oftware you can find in the Github repository below. A description of how the servo(s) are wired can be found in the code. We used a 12V / 2A wall plug to power the whole thing.
You are done! Ready to get haunted!
I recently found this awesome sounding metal cover in my workshop and decided to do some high quality recordings with it. I used AKG C414, a Neve Portic 5012 preamp my RME Bayface and some slight postproduction (compression and slight EQ).
The sound is open source and can be downloaded in 24Bit Wave here.
David Byrne also gets into mechanical sound creation with his “Playing The Building” installation. An old organ is equiped with electronics and pneumatics so that the organ-keys can be used to control motors, solenoids and pneumatic parts.
On Musical Robots and Robotic Musicians: Gil Weinberg at TEDxPeachtree 2012
The HiHat machine is part of the Drum Robot MR-808. It took some experiments until I figured out how this can be crafted into a high-performance working instrument: A HiHat is normally used in any track and plays most of the time!
This robotic HiHat is based on a normal drummers hihat, with two cymbals and parts of the hihat-stand. It also contains two solenoids (electro magnets), one for opening and closing the cymbals, on for the actual beating of the cymbal.
The force needed to open the HiHat is quite high, as it has to work against the force that closes the HiHat. The solenoid used here comes from a car engine starter. They have the most powerful solenoids, are reasonably cheap, easy to get at any car junk jard (or eBay) and operate at 12V. Perfect for low budget robotics!
The disadvantage is, that they consume roughly between 30 and 50A. Un-technically spoken: This is very much! I use server power supplies which can supply a current up tp 50A@ 12V.
I started with a standard HiHat machine (the full hardware Hihat Stand) and cut the lower part off. One thing you have to consider: a HiHat is default-OPEN, meaning that the spring inside keeps the cymbals separated when no pressure is applied. Only if the drummer steps on the foot-part, the HiHat closes. Replacing the drummers-foot with a solenoid (yeeha!) would mean that you would have a constantly powered solenoid, in this case about 35A, for most of the time (closed HiHat).
As we don’t want to fry eggs with the robot (solenoids can get quite hot) its recommended to reverse this mechanics, meaning that the HiHat is default-closed, and the solenoid is only powered when you want an open HiHat. I then removed the spring and let the gravity do the closing of the cymbals. Afterward I attached a fan inside the HiHat machine as the solenoid gets really hot for off-beat disco music. The huge car solenoid is only for the opening and closing of the hihat.
The actually beater is another solenoid which just hammers directly on the lower cymbal. It is used for both closed and open HiHat.
Josh also build the keys himself. Whoho!
The operational principle is that when stepper motors are back-driven, they induce a pseudo-sinusoidal alternating current. If this signal is amplified and connected to a speaker, you can listen to it as sound. The pitch of the sound is determined by the frequency of the wave, which depends on how fast the motor is back-driven. Higher speed will be a higher note. I thought this sound was interesting, so I wanted to make an instrument that used this mechanism to make music. This is an experimental instrument I built that uses back-driven stepper motors to synthesize sound.There are 49 stepper motors, one for each note in my four octave instrument. At rest, each motor floats above one of 49 disks, which increase in size exponentially as the notes ascend in pitch. The disks spin together, driven by a single speed-controlled DC motor. When a key is pressed, the corresponding stepper motor is engaged with the corresponding disk in the disk stack, and the disk back-drives the stepper motor.
Wooden Organ Built Around Stepper Motors to Create a Unique Synthesized Sound
I’m a big fan of Simplify 3D. Its a commercial software but its worth every 149$ that it costs. If you digging deeper into 3D-Printing you can take your pre-processing to the next level. I had the issue, that when printing a model with solid infill (100%) and 0.1mm layer height on an Makerbot Replicator 2 the base would show gaps in between the extrusion lines.
As the model should be water tight I made a simply test – blowing through the model. It was not watertight, you could blow “through” the wall. Holding it against the light you could also see that there were gaps in between the extrusion lines.
One thing with Simplify 3D is that you have a lot of parameters, which also interact from time to time and sometimes its unclear what change bring the solution.
I fiddled with a lot of parameters, including extrusion width, gap fill or infill extrusion width. What helped was to tweak the parameter “Extrusion multiplier” to 1.10 (formally 0.8). Like this I can make really solid model with out gaps of holes between the extrusion lines.