Ridiculously small Pipe Organ

Bought three organ pipes second hand on ebay the other day. Pitches (from lower key) are C, D and F#. Decided to make an electric organ out of it.

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Case are made of oak wood milled on my CNC milling machine with church like ornament windows. It is my first experiment with making simplified tapped corners on the CNC machine. Not perfect but it seems to work out. On one side there is a control panel with individual power adjustment for each pipe plus vibrate frequency and depth.

I have used an Arduino to control the fan motors because I’m lazy. It gives me the possibility to PWM control and modulate the pipes with a few mosfets (IRLZ24N) and minimum effort. If I want to add midi control in the future, this will also be straight forward.

I have used separate fans, from hot air guns, mounted straight under each pipe. This gives a really simple assembly with no valves to worry about. The down side is that the fan noise is quite audible trough the pipe sound.

All in all I am very happy with the looks of this thing. Less happy with the sound, and the possibilities are obviously quite limited with only three pipes.

I am quietly daydreaming of buying a full set of old church pipes to make a huge Serafin like contraption of it. The biggest problem so far seems to be that the parts must be transported from the USA to Norway, which is far from cheap.

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Double Pendulum

Double Penedulum

Grethe Mo was producing a solo theatre performance about (fear of) math. She wanted some kind of visual effect to visualize the beauty of math and numbers. Quick brainstorming with Anne-Sophie Eriksen and Kjersti Høgli led to this:

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A table mounted double pendulum. Ironically enough a demonstration of chaos; where the math and numbers break down.

The devise is made by home milled aluminium leftovers from the Grenland Friteater storage. All joints have ball bearings to give a long lasting pendulum. The finish of the bare aluminium parts are gently sanded to give a matte look and to remove scratches from the old materials.

Hamsterlife

Task: remote control a lot of hacked toy hamster to start, stop and light blue on command.

Given the number of hamsters to control (about 20) this was an opportunity to design my own Arduino based miniature microcontroller board.

Features:

  • IR receiver
  • H brigde motor driver for almost any motor voltage.
  • 3x LED open drain drivers
  • 7-30V power input w/battery monitoring
  • a little prototyping area

[will add photo of schematics here]

I used Pad2Pad for the manufacturing and used their PCB design software which was realy easy to learn.PCB

In future productions I will mostly use these cards to avoid extra cards, and reduce space and cost.

 

 

 

 

Design flaws found so far:

  • Motor driver gates need pull downs to make sure they are all “off” when microcontroller outputs are three-stated.
  • Motor drivers could with a slight change bee all galvanicaly isolated trough the optocouplers. This would be nice.
  • The third LED output PWM colides with the IR-outputs timing so I have to choose between dimming LED3 or using IR input. This could be avoided by choosing another output pin for this driver.

 

How to import a bitmap image into autoCad

AutoCad is great but hopless when it comes to import other formats. I needed to vectorize a metal band logo for a project. Long story short:

1. Open the bitmap image in Inkscape (open source vector editor) and goto path – trace bitmap.

2. Select traces and do object – ungroup

3. Path Break Apart

4. Copy the traced vector path with ctrl+c

5. Open openOffice Draw and paste with ctrl+v. You have to copy this way instead of saving to a common format to avoid great quality loss.

6. Export to Windows Metafile.

7. In AutoCad goto Insert – Metafile. Voila!