Let's Make Robots!

Yellow Drum Machine II

Gets funky with it's surroundings


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How to make a Yellow Drum Machine

Audiofile Engineering asked me to do a sequel to a robot of mine, Yellow Drum Machine.

It was named Yellow Drum Machine II (YDM II).

And.. sniff.. now it is no longer with me.

I have drowned it in polestyrene in a box, taped it up, and have given it to the lady at the post office.

It is flying to the states now, so that it can be first prize in a world wide promotional contest.

Sniff.. Count me in on the contest, I am going to win it back!


"TheCowGod" once wrote somewhere something about soldering friends.. and now I know he knows what he talks about.


I filmed you just before drowning you, here it is, to the meomory of you..



How to make / get your own Yellow Drum Machine



For more details of this project, I would like to start with this picture:

Is is taken from our house, looking up. To the left is a TV-areal. Please note how one stick is missing.. and how that left drumstick on YDMII is looking like something from a TV-antennae! I do not have much time for watching TV myself, but I told my wife that signal strength might possible increase if we took of that very one stick from there!

Also thanks to my wife for making the fine belt-track-pattern in black & yellow! (She did it while watching TV - and honestly nothing happened, picture is just as fine now as before)

To the right is my weather-stations wind meter. One might get the idea that the right drumstick on YDMII resembles that. Materials and inspiration can come from many places!


In most ways YDMII is the same as YDM, but for these differences:

A) The yellow "hat" instead of the huge speaker on YDM. I did not have more speakers like the one on YDM, so I spray-painted half a tennis-table ball and mounted it on top of a small speaker, that I mounted on top of the front part of a small flash-light.

This gives a perfect sound for the sample-playback!


B) YDMII has a tea-cup-speaker mounted on an old radio-antennae, the telescopic kind. By re-thinking (erh - in YDM, the original I did not plan or think much at all) .. by re-thinking ins- and outs to the standard picaxe 28 board used, I got some extra things to play with, and so I gave this fellow the possibility to twist the speaker that on YDM was placed in between the belt-tracks, bottom.


The videos:

Well - it is hard to do a number II; You have all seen a drumming robot now, and this one is even much like another robot of mine :)

I wanted the robot to play on a large fish's head. But I just could not find a fish with the right size head, that also had a good sound to it.

So what I ended up doing was just to carry the robot and a camera with me for about a week, shooting when/where ever.. And the last couple of evenings I have been editing little videos out of that material.

The programming / the code:

I ended up re-writing the "musical parts" of the core, and kept all the navigational from YDM.

I also created 3 extra "modes"; "Curious and playfull", "Tai Chi", and "Jam to musician". However, the basic code "Search and play" is now so expanded that there is no room in the tiny brains for anything more than that.

If you are the winner of the robot, you are very welcome to contact me, so I can advice you on how to enter the other "modes" by uploading other instructions to the robot, instructions I can send you :)


A nice detail IMHO is the on/off-switch:

It is two very powerfull (rear earth-material) magnets incapsulated in heat-schrinking plastic, with wires mounted on.

I tend to use this more and more over standard switches; It can be switched on/off by one hand.. and one can place a strip of plastic or paper between; Then it is a matter of pulling this out to turn on the robot.

It gives a better feeling; the robot is not something you just turn on or off; It wants to be on, but you can stop it by pulling the plug. Also this way you can attach a string to a door, attach the string to what's between the magnets.. and when you come home and open the door, you pull the string, and the robot greets you, and start it's business :D

I cannot remember where I got the pre-soldered magnets from, I bought a bunch.. But I will edit this as soon as I do :)


Congrationlations to the winner of this robot :)

I hope it makes you happy! I did my best to create and test it so it should be a good beat-maker for you in years to come :)

Get funky!



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It is a tea-thingey.. Half of one. It has a speaker in it, emitting the sounds from the microcontroller, which is clicks to the beat, and beep-sounds :) And then it twists around emitting the sounds in good directions.. no point really, just handsome :)

Those things are everywhere!  They are soo cool, I have to build one!!!


very nice design, good work

Those are so freaking cool. One day I will make a version of one. :D

oh my god

how not to be inspired by this creature?

i am tempted to produce another my ydm from scratch .. but i will not do it because it will become only an empty clone.....

glory to the God of the YDM


i am only worry because i do not see tech details about the brain of the beast...

it would be apreciated a block diagram wich make me undestrand how it korks

also i have no idea how to sample and play sound with a Picaxe...


finally this robot remanin , for any aspects, a mistery for me..


THIS was the robot that brought my attention to this site so long ago, and what urged me to eventually become a member of this fine community. It is truly an inspiration. GREAT WORK FRITSL! Long live YDM and YDM II, wherever they are! May we see many YDM variants in the future...

Hallo Frits,

I would just like to say one thing: I have seen your robot. You are genius.
I'd like to purchase one.  I understand you'd have to build it, and would like a quote.  Please email me at jargmarbin@jargmarbin.com

This is a great bot and I hope as an amature that some day I can possibly build something as memorble as this. thank you for being an inspiration to all of us.


Hi Fritsl,

Very, very nice and funny robot, I love it :)  I am a drummer beside being a robot builder, so this talks to me definitely :)


I love it !

it's great, it's a best robot ever !

robot for the pleasure

robot for the art


 i want more video, more music, more fun !!!!!!

contact me for the complete kit : ericteuh@hotmail.com