My Turntable Tower

April 10th, 2017

A few years ago a friend of mine gave me his old Syrincs M3-220 Monitor System which Satellites had given up service. Repairing them was quite straight forward as some diodes and caps had blown, probably in unison with the tweeters (as to who took whom down, I leave that to the pros). Finding replacement for the tweeters was a bit harder because mine was an older model and a fitting 6 Ohm (why?!?)  tweeter wasn’t available. I ended up with a combination of the replacement of more recent date, salvaged front plates and epoxy…

Ok, so I’ve good a pretty good sound system there. What now? It had been a long time since I’ve touched my turntables and I was missing the sound of vinyl quite a lot. Main reason I didn’t get the things out of their crates and connected them to a stereo is that I was simply too lazy and I didn’t find the right place for the setup in my room. My BassJump provided me with a bearable solution (both in weight and quality) for a while, but feeling the bass is something different.

Some time ago I was at an exhibition of Jay Gard and I decided I wanted to build something in that direction. So here it is:


Turn Table Tower


The front panel features a rotary switch for off/line in/phono/bluetooth (bt not integrated yet) and the volume and bass pots of the sound system. to have more control of the sound I added a Behringer EQ . It adds quite some noise, probably the power supply, but it’s alright. All in all I’m very happy with what I got. Vinyl is back in the game and placing my monitor on top of the box provides me with a nice home cinema sound.


I am in the process of getting the building plans done in Fusion360 as an exercise and will provide them here if anyone’s interested.

PLC Project: Some Specifications

June 1st, 2015

I could run simulations in my mind on what configuration would turn out how and how it would affect my further design, yadayadayada. Lets get some facts down about what I need, want to achieve, or simply have decided (be it out of lazyness, sheer desperation or from flipping a coin).


  • DIN rail form factor
  • AtMega2560 based
  • RS232
  • RS485
  • Ethernet
  • 12V supply voltage
  • nice to have: LED Indicators for IOs

Additional Features:

  • Relays (230V)
  • Power Outputs 5V/12V 1A
  • Optocoupler IOs
  • nice to have: all IOs optically isolated
  • nice to have: debounced limited outputs for buttons

As I write I started pestering reddit with my questions on [possible circuits] and [requirements]. Let’s see what it leads to :)

Yet Another Project: a PLC

May 27th, 2015

I’ve spent the past 2 years building machines and designing controller boards for them. These boards are all still in alpha status and I am quite sick of having to design the whole board anew whenever someone comes up with a new feature.

One could keep the whole thing extremely modular and design something around a master controller communicating with smaller boards that all have a certain purpose. But I want at least a certain functionality on one board to keep the wiring and communication programming as simple as possible. So currently I am thinking about building a stackable board that has the main processor and all the com I/Os on it that can be expanded by boards with extended features such as relays, decoupled outputs and such.

I was inspired by the [controllino]. I might as well buy one, but they seem to be in trouble with their part suppliers and I just can’t wait. Also, I want to do this by myself, learn stuff and make it available to everybody.

I did some research and stumbled over the [OpenPLC] project. I like what he did so far but I find the form factor a bit too clumsy for my purposes.

In the next weeks (and months, as these things tend to turn out) I will do some research/crowdsourcing as to different parts of the circuit and I will try to document it here. So whoever is up to such nerdy stuff: stay tuned :)

On KiCad

December 5th, 2014

Surely I mentioned here before that I switched to using KiCad as a circuit and layout program a while ago. I was introduced to it by my former employer and instantly favored it to the free version of EAGLE I had used up to that point. Since then I am trying to convince people to use it. Why? Because it’s free, it’s open source, and it gets better all the time. And I don’t see why people in hackerspaces should rely on crippled free versions of commercial software when there is a free open source alternative available. This post is a list of helpful links on the subject, mostly for me to remember ;)

more… »

What’s your addiction?

May 28th, 2014

It’s been such a long time since my last post, it makes me wonder if there is anybody left who remembers this blog (or its owner for that matter). Except, of course, those busy little spambots who drop by quite frequently, mostly trying to point me to addiction treatments lately. Could it be that the internet thinks I stopped blogging due to some drug problem? Well…

more… »

Tutorial: Using Textwrangler instead of the Arduino IDE

October 16th, 2013

Doing some more serious programming I became aware of some shortcomings of the Arduino IDE. What annoyed me most was the fact that it is impossible to customize all keyboard shortcuts. Using a German keyboard layout combinations such as shift+[ are almost impossible to achieve. A question on the forum led to a rather smug answer I should simply edit the source code and compile my own. I won’t. more… »

Diskokugel Progress 10/13

October 6th, 2013

Some months went by since I last updated on the state of my [Diskokugel] project. It might seem a never-ending story this one, but rest assured, I am getting there.

In the last months I started working on some of the more tedious tasks such as cutting, crimping and soldering connectors to 100 speakers and then mounting them into the framework. Then I started assembling them but thought better of it. At the moment I am missing a PCB that does the pre-amplification of the audio as well as converting the Arduinos signal voltage levels (0-5V) to those of the rest of the circuit (+/-6V). Such a circuit already exists, of course, but not in a format that would fit in my construction. Realizing how much cables actually have to be connected inside the Diskokugel, I decided not to assemble it temporarily because it would take ages to disassemble it again. So you will have to wait until I got around to design that PCB and ordered it.

Until then these 2 images will have to do:

Audiopanel 1.0

September 30th, 2013

I had some procrastinating to do the last two weeks. Being who I am, this usually leads to some kind of new project, in this case I finally started something I wanted to do for a long time. What’s actually new here is that I kind of finished it :) So I present you: Audiopanel 1.0.

Audiopanel 1.0

Audiopanel is an enhanced version of the [audioweb 0.1] I installed 2 years ago in my room. It’s a panel of 14 small speakers that switch the sound around like my [Diskokugel] will one day do and also is backlit by rgb-LEDs. It also has a “stereo mode” where 6 speakers each work as left and right channel. The lighting can be controlled in hue, saturation and brightness. Right now this is all done by hand, but in the future I hope it will all work via bluetooth.

What makes me proud is I made this mostly out of stuff I had lying around in my workshop somehow. I took electronic from older circuits and some broken boards and made it up as I went on. That’s why the stuff in the back looks so “modular” ;)

The whole rgb part still has some glitches. I used an HSVtoRGB patch I found in the [Arduino forum] based on formulas acquired [here] but it doesn’t seem to check out comletely yet. Also, since there is no separate GND for analog and digital signals in my circuits, the audio signal can have quite an influence on the dimmer when turned on loud. But I decided this to be a feature ;)

Using the stuff that also powers my Diskokugel, I learned quite something about the circuitry again. I know now that I could have saved my time trying to make it [louder] with a different amplifier setup by simply experimenting some with the existing pre-amp. There’s more headroom here :) Also the issue of the separate GNDs leaves me a bit concerned how this whole thing will work out inside the ball itself. We’ll see…

A Sign of Life

September 22nd, 2013

My last post is 4 months old, I would’t blame you if you thought I gave up on it all. But you should know better! In fact, a true connaisseur of yours truly, ruling out a terrible accident in which I lost both hands and my brain,  would know this can only mean I have been terribly busy making things(tm) happen. And indeed, things happened. Whether I made them happen or they chose to happen to me is a rather metaphysical question, but such subjects shall be covered elsewhere. In this post I shall restrain myself to a mere list of events. Depending on the subject, details might or might not be provided in other posts. more… »

Diskokugel Progress 5/13

May 28th, 2013

Time flies by rapidly and I’ve been busy making various things happen for the [Diskokugel] project. I am indeed determined to finish this one this year. I need this off my head ;) So what did I do? In short:

– I got fresh PCBs in from Seeedstudio and soldered 14 of them

– then I did a test with 96 speakers, after equipping all of them with crimped cables. Crimp till you cramp!

– I bought and tested a Bluetooth [Audio Module] and a [Bluetooth Serial Module] with Arduino attached. More about that in another article, though.

The PCBs came out well indeed this time and I was very happy to find that [c-base] has a reflow oven and hot air soldering equipment in it’s labs. This way the first half of what is to be Diskokugels intestines was soldered quite fast. While I was waitig there was plenty of time to cut, curl and strip of the isolation of 200 cables and the crimp and solder them onto 100 speakers. I get my lessons in Zen out of these tasks…

After that it was just a few more power and audio cables to crimp and then it was all ready for testing. Main objectives of this run were:

– check how the circuit acts on power-on

Diskokugel will have 200 amplifiers and they can draw _a lot_ of current. To reduce the current needed there will be measures to activate only a certain number at a time. That is however controlled by a controller that needs to boot up first and there is no control whats happening inside the switches of the individual boards in the main time. It turns out that as long as there is no audio signal, the circuits quiescent current is relatively low. That means I will use a relay to switch the audio in from ground to signal once the microcontroller has powered up. Easier than having to switch power on for one board after another :) 2 boards at full volume used about 1A at 12V. That makes about 150W for all Speakers at once. That also have to run through a voltage divider to provide +/- 6V and a virtual ground.

– check how serial communication works with a longer cascade of boards

The serial signal is put through 25 ics after all and there might be interferences. It works, but I had to set the SPI speed to 1/8th of the Arduinos clock speed. The fastest switching speed for 96 speakers was about 40ms this way. Since I had to lay everything out on a table, I had to use longer cables at some points. Once everything is mounted on the [icosahedron], it might work better.