Fork-o-Drumbot: A MIDI Drummer!

forkotitle

We just got word of a great project by [Vito] — A MIDI Drumbot made from an Arduino and scraps from around the house!

After learning some basics of programming microcontrollers way back in high school, [Vito] was excited to start using the Arduino platform. His first thought was to build a desktop milling machine for engraving his own PCBs. But after a bit of research, he soon concluded it might be a bit too ambitious for a first project, so he opted for something a bit simpler — A robot drummer.

Using some cardboard, a few elastics, a plastic fork, a 12V solenoid, an Arduino and a MIDI interface he had created the original Fork-o-Drumbot, able to tap a simple beat, using one note. After this initial success he grew excited to continue along the same vein of recycling things to characterize his entire project. Fast forward a few weeks of blog posts and he now has a fully functional MIDI drummer which even has a cymbal! They were even featured in the local newspaper after performing a duet with a local singer during an art exhibit called the Singing Balconies of Friedrichshain.

Stick around after the break for an extremely catchy rendition of Superstitious by Stevie Wonder, as played by the Fork-o-Drumbot!

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Making punch card programming a snap

About thirty years ago [H. P. Friedrichs] pulled off a hack that greatly improved the process of programming with punch cards. At the time, his school had just two IBM 029 keypunch machines. One of them is shown in the upper right and it uses a keyboard to choose which parts of each card should be punched out. This was time-consuming, and one misplaced keystroke could ruin the card that you were working on. Since you had to sit at the machine and type in your source code these machines were almost always in use.

But wait, the school acquired a dozen of the TRS-80 computers seen in the lower left. They were meant to be used when teaching BASIC, but [HPF] hatched a plan to put them to task for punch card generation. He built his own interface hardware that connected to the expansion port of the new hardware. Using his custom interface a student could create a virtual card deck that could be rearranged and revised to correct mistakes in the source code. The hardware then allows the virtual deck to be dumped in to the punching machine. This broke the bottleneck caused by students sitting at the punch card terminal.

We think that [HPF] sent in this project after seeing the antiquated hardware from that 1970’s calculator. These hacks of yore are a blast to revisit so don’t be afraid to tip us off if you know of a juicy one.

Marvelous Magnetic Machines

[HP Friedrichs] wrote in to tell us about an upcoming book titled Marvelous Magnetic Machines. Ordinarily, we skip over promotional hype. After watching his promo video though, we couldn’t help but share. We want a copy of this book. In this book you’ll find details on how to build a number of different motors from scrap. You can see several variations in the promo video. He also notes that the music was created by himself and some friends a few years ago. If [H.P. Friedrichs] sounds familiar, it is because he’s been sending us fantastic projects since at least 2006.

DIY Diodes

[H. P. Friedrichs], the creator of the Static Bleeder has created his own diodes. Using household chemicals, a film of cuprous oxide was made on a copper pipe cap. Cuprous oxide has been one of the first known semiconductor substances, has a low forward drop but is an otherwise asymmetrical conductor, odd V-I curves, and some neat photovoltaic action. The apparatus seen above is used to bring a piece of lead (in this case, solder) into contact with the salmon-colored cuprous oxide while electrical connections can be made to the binding posts at the front. What are your thoughts on this device?

Static Bleeder

When you are in the middle of the desert, pretty much every solution to a mechanical or electrical problem is a hack. [Sgt.M] who was deployed in Iraq sought out the help of radio guru [H.P. Friedrichs] about a static problem he was having. When dust storms would blow in strange things would happen in camp. Humming and crackling could be heard and [Sgt. M] actually had an electrical arc from a lamp to his hand at a distance of about 2 feet.

[Friedrichs] helped him find the problem. Their antennae were acting as static electricity collectors in the dust. All that dust friction in the dry air constantly built up a charge. The solution was simple, discharge the electricity at the antenna when it isn’t in use. Several solutions are outlined on the page, so check them out.

Using VFDs as amplifiers

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[HP Friedrichs] sent us this cool writeup on how to use scrapped Vacuum Fluorescent Display tubes as amplifiers. For those unfamiliar, a VFD is a display device common to electronics.  Many have been replaced by LCD, but you can still find them in modern products. [Friedrichs] points out that his 2008 ford has a VFD for the multimedia display.

Since these units are basically tubes, he figured that you should be able to use them as a tube amp. After some testing, he found it to be quite adequate.  The project includes tons of background information on how tubes work, how VFDs work and how to utilize it for amplification. In the picture above, you can see him using one (middle) to amplify a home made radio (right).

I’m still out of town extra


I received some good stuff via the tips line while I’ve been making an extra stop after Shmoocon. I spent the day helping my less project endowed family run some new wiring (and made some awesome sparks in the process.)

[Damian] sent in his customized version of the classic Atari 2600 adventure game.
[iraqiGeek] sent in his efforts to use the six-axis controller. He used lib-usb and PPJoy to create his own app.

[HP Friedrichs] sent in this interesting post on building military style power supplies. Good stuff if you’re into building your own gear and like interesting chassis designs.

[John] sent in his version of the new KITT’s light bar. (You know you watched it.)

Got something good to share? Use the tips line.

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