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Under Re-Construction

Details: Published on Sunday, 17 March 2013 05:35

This website runs on the Joomla content management system. It was running on an older release of version 1.5, so I dutifully upgraded it the the most recent release, 1.5.26. Two days later, the site was hacked.

Now it is running on the latest release of Joomla 2.5. I was able to migrate all the articles and users over, but not the look. Which is why it looks so plain right now. It will get spruced-up over the next few days, but it will look different than it used to - better I hope.

Hand Clap Pedal

Details: Published on Sunday, 17 March 2013 16:18

This is my first attempt at painting a custom pedal. Up until now, I have always used inkjet printed vinyl stickers on my custom pedals.

The pedal is built around the hexinverter.net NeinOhNein Clap circuit board, a clone of the clap sound from the TR-909. Hex Inverter has some great products including a whole series of 909 clone circuit boards.

The board is intended to be used in a modular synthesizer which supplies +/-12 or +/-15 volts. I wanted to use a standard 9V pedal power supply, so I did some testing. The circuit does not work well with +/-4.5 volts, so a virtual ground circuit was out. By not working well, I mean it had a hiss. I have noticed that with other circuits when trying to run them with very low voltages. So, I used a TC1044S charge pump chip to provide the -9V. I added an LED illuminated push-on/push-off power switch, a big button to trigger the clap sound, and a trigger input jack so the sound can be triggered by a drum machine or sequencer or whatever. I wired a diode in series from the jack and from the button to keep the voltage from either source from flowing into the other.

Building the electronics was relatively straightforward. The real project for me was making the enclosure look good!

Anatomy of a Drum Machine

Details: Published on Tuesday, 31 July 2012 18:42

This is the story of the design and development of the Delptronics LDB-1 Analog Drum Machine with a focus on the technical details.

I had been studying analog drum circuits for about a year, including both classic drum machines and more modern drum circuits and modules. In January of 2012, having just finished several projects, I felt it was time to dive into building some drum circuits. My goal was to build a small, low cost drum machine, and I knew that the first step was to get the sounds right. I breadboarded every drum circuit I could find and compared the results with samples from the classic drum machines, particularly the venerable Roland TR-808. I worked on it full time for two weeks. By the end of that time, I had the circuits refined and tuned and sounding just the way I wanted them.

The one sound I could not get quite right was a rim-shot. The closest I could get was a woodblock. I figured it was time to build a prototype and I would get back to the rim-shot sound later. To my surprise, I got a lot of compliments on the woodblock sound, so I kept it as is.

I then went through the process of choosing a microcontroller to be the brains of the drum machine. That process is described in more detail below. I worked out the basic code for a microcontroller triggering the drums and built the prototype. Having worked out the bugs, I designed a printed circuit board and built several devices.

The most time-consuming step in the development of the LDB-1 was to program all of the features. I went through many iterations of the code to get every feature of a classic drum machine into the LDB-1 with an easy to use interface. A three month long beta test cycle really paid off.

When development was complete, there was still a ton of work needed before it could go to market, tasks like writing the user manual, sourcing the components, assembly, the design and production of the enclosure, and so on.

Original Prototype	Final Production Model

The Circuits

The rest of this article is a description of the LDB-1 circuits. The information presented below should provide you with all of the information that you need to understand and even modify the LDB-1. If you have specific questions not answered by this article, please feel free to contact me. As you read the article, follow along with the LDB-1 Schematic .

Giant Little Drummer Boy

Details: Published on Wednesday, 18 July 2012 18:29

I build a giant version of the Delptronics LDB-1 “Little Drummer Boy” analog drum machine kit.
It is pictured below next to the standard kit to show the scale.

The actual assembly was not difficult. Of course, when I assembled the kit, I skipped all of the parts that would eventually be panel mounted. Instead of getting all new panel mount jacks, I could have positioned the PCB at the back edge of the enclosure and drilled holes for the board-mounted jacks to come through. However, lining up the holes is such a hassle that panel mount parts are just easier. Once the parts were soldered on the PCB, I soldered wires for all the jacks, buttons, LEDs, etc to the board, then to the panel mounted parts.

Here is a color-coded diagram of the LDB-1 PCB that will be very helpful if you want to build it with externally mounted parts. The pads that you need to connect to are green. Some pads are gray to indicate that there is no panel connection, just for extra clarity. I colored the ground pads blue so you know you can wire them together on the panel. Keep in mind that this is a bi-polar circuit, so the negative power connection is V-, not ground.

All told, it was about $100 in extra parts, plus $140 for the kit, plus about eight hours of work. The result is well worth it. I now have the biggest Little Drummer Boy on the planet! Of course, being the inventor of the LDB-1, I had a head start, but I would love to see what other people do with the kit.

These were the extra parts I needed, with links for some of the less generic items:

Bender Sequencer with Monotron and Gakken Synths

Details: Published on Sunday, 22 April 2012 17:47

The most commonly asked questions about the Bender Sequencer are: “I have/want to get a Bender Sequencer, so how do I hook it up to my ___?” and “What is the easiest device to hook up to the Bender Sequencer?” Well, here are the answers.

In this article, I will show how I use the Bender Sequencer to control the Gakken SX-150 and Korg Monotron mini synthesizers. I chose to discuss both the SX-150 and Monotron in the same article because they are popular, inexpensive, and very similar. As has been oft noted, the SX-150 is packaged with a magazine that includes a photo of Gakken showing the SX-150 to Korg engineers in 2008, two years before the Monotron was released. Coincidence? Not likely, but let's put aside conspiracy theories and get to work.

The main similarity between them is that they both use a ribbon controller to control the pitch. The SX-150 uses a stylus touched to a ribbon and the Monotron uses a pressure sensitive ribbon. Slightly different hardware, but exactly the same concept. In both cases the ribbon is simply a variable resistor. You could disconnect the ribbon and hook up a simple potentiometer (pot), and the synth would work exactly the same. That is a key point. After all, the Bender Sequencer is designed to connect to a device at the pitch resistor (variable or not). So, these two devices are perfect candidates for sequencing.

Stuff For Sale

Details: Published on Monday, 16 August 2010 23:01

MickeyDelp.com has some cool products for sale! Click on a product name for all of the details, such as pictures, videos, instructions, schematics, etc.

Bender Sequencer

The Bender Sequencer can turn any device that makes sounds into a rhythm or melody machine by playing a sequence of notes. The Bender Sequencer was created specifically for controlling devices that were never even designed to be controlled! Those devices can be electronic musical instruments, circuit bent toys, electronic kits or your own circuits. The Bender Sequencer has a variable resistor output that can be connected to a circuit the same way you would connect a potentiometer, and a trigger output that can be connected anywhere you would connect a switch or pushbutton.

Ring Modulator

Classic passive ring modulator effect! Separate input, carrier and output jacks. Built-in carrier oscillator with frequency and amplitude control. Plug in any source – guitar, keyboard, synthesizer, voice, etc.

Guitar Meister

Play guitar like a master with no experience necessary! The Guitar Meister is a little electronic device that makes a big guitar sound. Simply plug in any PlayStation 2 guitar controller and play real guitar sounds just by pressing the buttons. Four voices included: acoustic guitar chords, electric guitar chords, electric guitar notes and bass guitar.

Mickey Delp dot com