Making the Roland DXY-1200 pen plotter wireless (bluetooth) for about 10€

Easy and cheap hack

My office is quite cluttered with hardware. I’ve been toying with chiplotle lately but doing so meant cleaning up my desk and make room for the big clunky 80ties plotter. Chiplotle just sends serial commands, so why not over bluetooth. I ordered a


HC06 serial bluetooth module widely available


and a


serial to ttl converter powered by USB


just hooked it up together with a DB9-DB25 convertor and it just worked… pairing the HC06 was with the code 1234, instead of OSXs default 0000. besides that, no problems.

I set my



serial_port_to_plotter_map = {‘/dev/tty.HC-06-DevB’ : ‘DXY-1300’}

and of we goplottersetup

The whole setup is usb powered and works really smooth. I can now leave the plotter at a convenient place in my office and play with it… wirelessly yay!





flashing the mi mini wifi router with OpenWRT

I lost connection with the mi mini wifi router after following this procedure. I flashed u-boot to the bootloader, and it succeeded, but It would no longer boot the firmware.
Apparently it did boot into u-boot, but to find that out I had to get a serial console. Instead of getting a usb serial to TTL I tried using a raspberry pi and the GPIOpins. It worked.

opening the MI mini wifi

two screws hold i together, opening it from there was a bit harder. You have to forcefully get underneathe four little hooks at the bottom front of the device

holes in the router

after opening it, all we need is accessible.

soldering a serial port on it

I used an old connector I had lying around, easy t get to the breadboard

nice solderpads, easy connection

next step involves the RPi

you can then hook it up to the RPis Tx, Rx and GND pins. As both devices use 3v3 TTL, no extra circuitry is needed

ssh over to the RPi

once your logged in, type

$ minicom -b 115200 -o -D /dev/ttyAMA0

to start a serial console on the RPis GPIOports. Once it runs, boot the mi and you should see this

Screen Shot 2015-06-09 at 20.46.36


now the easy part

connect a UTP cable from a LAN port directly to your computer, and assign your PC a manual address in th 192.168.1.x but not

start the http server on the mi

MT7620 # httpd
raspi_read: from:40028 len:6
NetTxPacket = 0x83FB5080

KSEG1ADDR(NetTxPacket) = 0xA3FB5080
Trying Eth0 (10/100-M)

Waitting for RX_DMA_BUSY status Start… done
HTTP server is starting at IP :
HTTP server is ready!

Keep going WEB failsafe, rx_counter=0 , GoGoGo!!!

point you browser to

and upload your firmware…

I flashed openwrt-ramips-mt7620-xiaomi-miwifi-mini-squashfs-sysupgrade.bin

connect to internet (cable)

and start setting up OpenWRT

$ opkg update && opkg list luci-*
$ opkg install luci-ssl

$ /etc/init.d/uhttpd start
$ /etc/init.d/uhttpd enable

$ uci set wireless.@wifi-device[0].disabled=0; uci commit wireless; wifi


make sure it boots from the flash partition

by default it waits for a tftp image to be transferred, so:

$ printenv

and take a look at the env variables

$ bootcmd=tftp

this should be

“bootcmd=bootm bc050000”

so set it and save it

$ setenv bootcmd bootm bc050000

$ saveenv

now reboot, test and go and configure it

Trix Algorave

After a month of trying to run clojure REPLs and trying to get quil to talk to overtone I was ready for my first livecoding performance. Trix algorave was a great event to meet like minded people talking about code, music and creativity.
Using quil means I was doing graphics and I was supporting the music of bohrbug. The hardest part was getting two computers to be in sync on both sound and music. I could use some insights on that.
For now we were using OSC and two separate SC servers. I have a hunch that running one SC-server for both music and visuals could greatly improve the sync and the amount of data that can be shared realtime between the two interfaces. Any ideas on that are likely to be moderated very quickly 🙂

The evening was continued with Insomniark en Exoterrism both using pure supercollider and hardware controllers for quickly interfacing with the code to be concluded with a streamed set from Alex McLean. That last set showed of an impressive coding style, both fast and well executed clearly showing experience is important…

some images:

KaOSbeat & Bohrbug @ trix algorave
screen cap output from 2/3rds into the set
screen cap output from 2/3rds into the set
Exoterrism at the knobs and insomniark’s hardware in front of it
Alex McLean Live from UK

onto the next algorave Here’s the full code repo for the visuals and the full set on youtube below (atm without sound, hope to get the recording ASAP)

OHM2013 moldover show

I was at OHM2013 for some hacking, meeting friends and meeting new people. One of them was @moldover and he brought his gear (mojo & robocaster)! As I’m building my own controller (for visuals and vegetables) I started talking to him. He was going to perform later that day at Rainbow Island. So I offered him a live VJset and after little to none preparation time I was able to fix my setup enough to get going. And so we did. And because it was fun, we did it again the next day. Inspired by the great place Rainbow Island is I gatherered some (retro) pixels during the day from dancing my little ponys to the masks from hotline miami. The people for rainbow Island added more beamers and splitters and lights and fire and the results was fun.

some pics

full video

Moldover full show 2-8-2013 @ Rainbow Stage - OHM2013 - YouTube

designing a 2D cityscape in processing

For the mix office redesign I designed a magnetic and writable wall (9.6 by 2.4m) but to just have an empty white board, well that would be a bit boring so I added a cityscape at the border, generated by processing, and the “oblique sky” clouds formed by the words of Brian Eno’s Oblique Strategies, also generated by processing. Both ideas were developed through trying and testing and getting immediate (visual) feedback while coding. At each run of the code, I took a snapshot. Next Time, I’ll look into autocommiting with a tag in github so I can link snapshots back to the right code. If you put the snapshots in a little movie, you can see the evolution of the idea and also the mistakes along the way 🙂

Feedback was given from the oblique strategies themselves as they hinted me to try other things when I saw them rendered on the screen.

Code on github

obique sky


Final result


inspiring drawing by a colleague


do it

dataviz using physics (part2)

I quickly added real data to the visualisation so now what you see actually means something. Every circle represents 20 persons either older or younger then 20 living in muide-meulestede-afrikalaan, a district in Ghent, Belgium.

before the toggle
before the toggle

Then I made a toggle button to make kids take up more space. Also in areas with less open space an extra factor will make them even bigger. The results seem readable to me and the toggle makes it easy to compare between not taking additional parameters (open space &demographics) into account and taking the extra info into account.

after the toggle

But who am I to decide over the importance of kids and open space… let’s add sliders.

with sliders

The sliders let the user decide which parameters are important and get immediate feedback. neat!

code at github.



Dataviz using box2D

Data. We’re creating more of it every day then ever before. Big companies are using your data it and you might (not) be happy with what you get in return. anyway they are crunching your big data come up with big numbers or even a score for your profile.

Besides not being very transparent about the algorithms most of the time, they create a currency you need to trust based on a gut feeling, but that’s another story.

A good trend is more and more governments and institutions are opening up their datasets to let the public access their data. Whether it is because a governments is legally obliged or a company/institute believes it can benefit from opening up their sources, we have access to some data to play with.

I’ve been reading up lately on the subject of data, and I went to where I was inspired. @flowingdata also compiled a nice list of blogs/sites on the subject on his site.

Working with visual data has always been of interest:

Armed with a Silicon Graphics Indigo 2 Extreme desktop workstation with R4400 processor, four gigabyte hard drive, and 128 megabytes of RAM, Borchers uses IRIS Explorer an interactive 3D data visualization system to analyze data. The team’s datasets range in size from four to 20 megabytes (based on foot scans producing 300,000 points in x-y-z spatial datasets). 1999 web 1.0 link

Now that I have 128Mb of ram I thought I should give it a go. I chose processing as I used it before for different tasks and it’s is a good protoyping tool used by dataviz pro’s to make stuff like cascade (built by @blprnt  at @nytlabs). Besides that, I recently had a nice re-intro to processing  by @vormplus and I followed a workshop @p5Ghent.

If you’re interested here are some other tools as well

Having just missed the Ghent appsforghent challenge it felt a bit odd at first to use the sets, but I’m a local, and you should think local(but act global, which is why this post in in English).

The Idea

An interactive explorative tool that allows you to visualise data on a map (of (part of) Ghent)

I wanted to express the fact that this particular place where I live is crowded, densely populated and this is why I started thinking about using physics. Particles bumping into each other, fighting for space.

This is far from finished but I thought I’d share this already.

It’s on github, next up is giving kids more space by mapping the demographic pyramids on this data and making the particles representing kids bigger. With the press of a button I could show what impact building a new high-rise flat will have in a certain area.

The user could set the desired sq meters of outdoor area per capita and see which neighborhoods are comfy and which are crowded. Much more thing a possible, but also a little more time is needed.

Right now it reads in map data from an SVG file, converts those shapes to box2D entities and populates them with particles.

the small points mean < 1 person!

The screenshot isn’t using the correct data yet but you don’t need a lot of imagination to see that it has more potential then the original

just using a map to display map related is a start and while that is an option on the site (which is a great source of info btw, well presented and all that) this static mapping doesn’t really say a lot. It’s crowded. period.

The exploration

I’m just using this example to explore the possibilities of using physics for making sense to data. This doesn’t necessarily mean you need to map phyisical properties to your data that in real life exhibits the same properties. I can imagine  that if you need to sort certain types of data it could make sense to let them have a different density so some data floats while other would sink, while you’re actually visualizing eg. twitter vs. facebook.

to be continued

extracting earth earth’s entropy for generating aliens

I need to fill a lineair space and generate a continuously evolving series of abstract drawings. All this to fill up some leftover space at the office (to make it less boring). In particular a 30 cm (1ft) high space below the windows. This stretches along the windows and is quite long.

To avoid repetetivity, I chose to seed the algorithm with somewhat random data in the form of a series of pixels extracted along the image of the earth.


I work at a hi-tech internet  innovation research institute but are in no way affiliated to Silicon Valley, we came up with the idea of connecting Ghent with a line to silicon valley, the result, is not that interesting to show, but it is a line, one pixel wide. It is however an interesting series of pixels, where neighbouring pixels are related.

but what to  to with pixels.

It’s not an awful lot of data. A color, an RGB value(3 times 8 bits), a sequence number perhaps, maybe the relation to the neighbor? Does it within a certain threshold have the same amount of blue, green and red? Or does it represent a bump? As it comes from a terrain map, maybe  it can represent an altitude. not sure yet.

But what I was looking for was more something that contains enough data to allow to generate specific images

You’re looking at it, just above this sentence. after parsing the pixel color data from it, half an alien is generated according to this procedure.


which is then mirrored and completed. Repeat this for every pixel and you get a lot of different aliens, first 25 of the above line, pictured below

[processing code]

* aliens

PImage lijn;
int px = 0;
int pxmax = 5;
int offsetY = 0;
int alienSize = 160;

void setup() {
size(pxmax*alienSize, pxmax*alienSize);
lijn = loadImage(“lijn.png”);

void alien(color code, int px){
//int Rr = Integer
int offsetX = px – (pxmax*offsetY) ;

rect((offsetX*alienSize),(offsetY*alienSize),alienSize, alienSize);

String alienR = Integer.toBinaryString(parseInt(red(code)));
alienR = “0000000” + alienR;
alienR = alienR.substring(alienR.length()-8);
String alienG = Integer.toBinaryString(parseInt(green(code)));
alienG = “0000000” + alienG;
alienG = alienG.substring(alienG.length()-8);
String alienB = Integer.toBinaryString(parseInt(blue(code)));
alienB = “0000000” + alienB;
alienB = alienB.substring(alienB.length()-8);
for(int i=0;i<8;i++){

for (int col = 0 ; col < 4; col++) {
for (int row = 0; row < 8; row++){
if(col == 1) {
String[] alienRArray = alienR.split(“”);
if(parseInt(alienRArray[row+1]) == 1) {
rect((col*20)+offsetX*alienSize, (row*20)+offsetY*alienSize, 20, 20);
rect(((7-col)*20)+offsetX*alienSize, (row*20)+offsetY*alienSize,20,20);
if(col == 2) {
String[] alienGArray = alienG.split(“”);
if(parseInt(alienGArray[row+1]) == 1) {
rect((col*20)+offsetX*alienSize, (row*20)+offsetY*alienSize, 20, 20);
rect(((7-col)*20)+offsetX*alienSize, (row*20)+offsetY*alienSize,20,20);
if(col == 3) {
String[] alienBArray = alienB.split(“”);
if(parseInt(alienBArray[row+1]) == 1) {
rect((col*20)+offsetX*alienSize, (row*20)+offsetY*alienSize, 20, 20);
rect(((7-col)*20)+offsetX*alienSize, (row*20)+offsetY*alienSize,20,20);
if(offsetX == 4){
void draw(){
color code = color(red(lijn.pixels[px]),green(lijn.pixels[px]),blue(lijn.pixels[px])) ;
alien(code, px);

[/processing code]

nyanchat – how to discourage spam in realtime chat enabled webapps

On the dayjob we created this nice platform where you can talk about tv programs on the second screen. We deployed it as villavanthilt and enabled everyone with a webbrowser to talk along with the live TVshow and share the conversation. This all went well until we launched the realtime wordcloud as an app on the platform. It renders a wordcloud as you type of all messages passing the view. The problem is people started spamming to get their word in the cloud. After one evening getting loads of spam, deleting loads of users who recreated their account, we decided to make it stop…

Of all the cruel ways we came up with to punish spammers, or all the gentle ways of changing their behavior, there was one that seemed spot on. As a plus it was easy to implement, needed because the show ends in just two days.

  1. find spammer
  2. I think  you noticed the spam, just click it to open the spammers profile
    Notice the two red buttons, one is remove user, the other is mark as spammer

    spam mainly comes from uneducated kiddies, not viagra sellers as there is bot protection
  3. mark the user as spammer, a websocket message is sent to the user forcing a reload, and making the villachat…

    nyanchat, replacing the spammers(mine in this screenshot) text input window with nyancat
  4. The user could still log out and create a new account but their logout (afmelden) button is gone, there session stays open and they can’t create a new username.
    regular users can logout

    spammers can't sign out, button is gone
  5. thanks nyancat
  6. As a bonus the nyansound is there too and the session stays signed in for four days. That should teach em. Oh yeah talking about teaching clicking on the cat opens the wikipediapage on spam, educating the user.

Feel free to check out, but don’t make me nyan you

    Thanks to everyone who helped thinking up this and other ways to punish/educate spammers. Happy spamming,I’m coming to get ya!