The project as it looks so far :
I ordered a set with steppers, motor-control and psu from ebay, and I’m waiting for it to arrive(The seller said 10-12 days, so maybe if I am lucky next week). It should be 1.7NM motors and a more or less “plug’n’play” set.

I intend to drive the motors using a old computer running linuxcnc. linuxcnc looks real neat, but might prove to be hard to set up.

The construction

I am looking at two set of plans at the moment

How-to-Make-a-Three-Axis-CNC-Machine-Cheaply

This was the building plan that made me decide that this was a possible task. But there are some issues with the construction I don’t like, especially that it uses belts. They are hard to find and they are not cheap.

JGRO’s plans

This is a free diy plan. it can be found here : http://www.cncroutersource.com/cnc-router-plans.html

It uses threaded rod instead of belts. And the overall construction looks simpler.

Materials

Although I do want to do “fabbing” using a extruder at first I think that there will be enough work for a couple of days getting the mechanics and electronics up and running. Just as there is a lot to learn about g-code and all sorts of 3dmodelling.

To begin with I want to cut using a dremel tool, maybe a more powerful spindle(?) to be able to cut wood – if I have enough power in the steppers.

You might ask what do you want to make / “fab” with a 3 axis cnc machine?  I can come up with a lot of different small things like “coat hanger”, “coffee filter”, “PCBs” but I guess that it just boils down to: ” I think its a very fascinating technology and want to play with it”

I googled around but weren’t able to find such a utility. But i did find cli-sip client pjsua, based on pjsip. Its posible to use it in conjunction with a shell script.

Scripting

jacob@vps:~./control.sh sip:108329@foobar.com "wake up you lazy bastard!"
Is the basic usage i wanted to have. In order to get this functionality there are two steps.

Generating wav file

I ust use text2wave, from festival, which is available as a package on ubuntu.
echo $2 | text2wave - -o message.wav

$2 to use the second argument, and pipe it to text2wave. Let text2wave read sdtin and output a file message.wav

Call and play the wav file

pjsua_app --config-file=test.conf --play-file message.wav $1
Here the magic is in the conf file. Its a rather straightforward to use, and the documentation is good.

# we don't want the host's audio device
--null-audio
# SIP parameters
--realm domain.com
--registrar sip:number@domain.dk # DNS SRV, or FQDN
--username USERNAME
--password PASS
# default of 55 will be rejected as being too short by sipX
--reg-timeout 3600
# auto-answer all calls with "200 OK"
--auto-answer 200
# automatically loop incoming RTP to outgoing RTP
--auto-loop
# mix WAV file into the audio stream
--auto-play
--auto-loop
--duration=60

This is based on a config file i found somewhere, can’t remember where. There a a lot of other options, pjsua handles nat quite nicely as well. It was easy to test it at my homebox, behind a router, just be sure to set an external ip address.

Now this will call and play the message, but it wont stop pjsua. It will just sit around waiting for someone to call. I couldn’t find any nice way to handle this, but since pjsua reads stdin for commands, it possible to pipe commands to it.
echo "sleep 60000 q" | pjsua_app --config-file=test.conf --play-file message.wav $1
So sleep for 60 seconds, then accept the next input from stdin, the “q”uit command.

Generally this configuration is set for 1 minute, it might be necessary to tweak this.

Frustrations

There is/were a bug in the tarball, that meant that it wouldn’t run if it couldn’t find a soundcard, since it should run on a vps this is quite annoying. But in the svn version its solved, so if you want to do something like this, use the svn version. Other than this installation is straightforward.

When working with cron, remember to use full paths. In the control.sh script the better solution were to add a cd working directory, in order to have all the paths correct. This were quite annoying to debug, as the script would run from the shell. And just fail when added to the crontab. Furthermore mails from crontab were delayed, so i couldn’t see the output. I did get someone to look over my shoulder and spot the bug.

That doesn’t mean that i haven’t been coding small hacks, just that i haven’t posted them. But now is probably a good time to show some of the stuff.

As the title suggest it has something to do with processing.org. I have been using processing on and off for some time. Its is really nice when you want to make a quick hack, or as its called in processing a “sketch”.

In no particular order here is some of the fun stuff made using processing.

General remarks

The following sketches and their sourcecode have served as small hacks, hence don’t expect nice comments or optimal algorithms…

shrinkImage

It is possible to remove the line from a picture representing the least amount of information. The algorithm evaluates every pixels “weight” as the absolute difference between the different color channels (r,g,b). And then finds the “lightest path” from the bottom to the top.

This means that “prominent features” won’t be removed or change size when shrinking the image. Here the definition of “prominent features” is high difference in colors between the neighboring pixels.

Have a look at shrinkImage

Room for optimizations :

Eventhough its quite quick at calculating the weights and finding the lightest path, it does so in every iteration. Letting it use a bit more memory and just recalculate the changes when removing a line should speed it up. I found a huge speedup when just having an array with the weights from the last and current line, when calculation the path, so not only would saving all weights require a bit more memory it would also slow down the first calculation. But I’m sure it would give a significant speed up in the next iterations, and a lot of +-1 frustrations

helloFoo

There a some quick getting to know processing hacks, this is one off the. helloFoo

One of the very cool things about processing is the ability to use openGL, so originally this sketch uses openGL. But applets and openGL isn’t exactly the best combination. It can be done, but since it doesn’t work for me (firefox, linux openJDK JRE) i just converted it to standard java graphics. And the effort required to do this, is remove an import and don’t say setup(400,400, OPENGL) but just setup(400,400). This is trivially true the other way around. If you want to use openGL its quite easy.

The sketch is just bouncing balls, when going away from openGL I reduced the size and number of balls, in order to get a decent animation speed.

FooIII

Again used openGl originally FooIII

Some satellites rotating around some satellites rotating around some ….

sndHello

yes sketches tend to have silly names : sndHello

From Clifford Pickovers  book : Computers, Pattern, Chaos, and Beauty – graphics from an unseen world (p 39 section 4.3 snowflakes from   sound)
Draw symmetrically and in “polar form” the fft of the sound, hence creating snowflakes based on the sound.
Music by David Rovics
Choppy sound I had some problems with the sound when run as an applet. You might have better luck using the jar directly or by downloading the sourcecode and running it with processing

Slit-scanning

The former applet relied on an external library for the sound, ther are quite a few libraries available. I did use GSvideo to hook up my crappy webcam and do some video effects. I experimented with slit-scanning in different ways.Unfortunately this won’t run as an applet and it might only run on Linux.

By creating a cube of the images, where the z-axis represents time, its possible to play back different parts of the movie from different layers in time. Which makes for some quite interesting and dizzing effects.

For example a time buble where playback is delayed around a “bulge in the timespace continuum” :s (a video of some guy playing with it (timebuble1.avi) some sourcecode for a similar effect where the mouse pointer moves the buble (TimeCube.pde) another more “traditional slitscan” (CamWarpTime.pde) .

In general there is plenty of room to fiddle with the code, there a functions like selectSlice or initQueues where its decided how to slice time. its great fun to play with..

The very short desctiption :

inspiration from an example of homogeneous coordinates in my linear algebra book and lectures about lineartransforms.

There is a jar, with sourcecode, if you want to se it “live” or twiddle with it.

tegneri

I made have generated quite some random attractors.

Now I need to find the most beautiful ones, and I need your help!

I have created a voting system, where 3 attractors line up and you select the best one. The votes are then accumulated and and overall top 10 is generated.

Strange Attractor wars

It is heavily inspired by kittenwars.com.

I have been hacking away on this far to long. But expect an article with more details on Strange attractors and probably more features in the “war” application. (like top 100, biggest looser, most victorious etc).

Now just go and make some votes

I got around to hacking some code together for a simple DTMF dialer on the mobile.

Its functional and simple. Enter a number, click ok and it will play the correct sequence of tones. It’s even possible to tweak the duration and pauses.

I have only tested it on my own Nokia 6300, but as far as I can tell it should run on most java enabled mobile phones.

Here are the jad and jar files. If you want to run the program download them to your mobile and have fun.

• dtmf jad
• dtmf jar

At the moment it converts + to 00 and removes +45, as this is appropriate for a danish setting.

Here is the sourcecode if you need to make changes.

DTMF sourcecode

Using Netbeans

I used netbeans 6.0.1 and it was a mixed pleasure. Creating the the flow using a drag’n’drop interface, is well nice for something small and simple as this, but I found that it soon got frustrating. There’s no API to look in, and you have to use the mouse all the time.

This is the basic flow of the midlet. It was very quick to set this up, and it were indeed a pleasure to start with. Somewhere along the way a made a mistake, which the flowdesigner and codegenerator couldn’t handle. And no matter what I tried I couldn’t get rid of it, I knew exactly what i was. I had misnamed a variable and managed to let the generated code go into a never-ending recursion. (something along the lines of: private TextField foo() { return new TextField(Foo);} ). But no matter what I tried it just wouldn’t get back to normal. In the end I just created a new project, remade the flow stuff to what you see above, and copied a few functions over.

And the flowdesigner is quick to work with, but I get a nagging suspicion that if you are going to make something a little more complicated than this it will be an annoyance. You might know exactly where and what to change in the source code, but do you remember where to point, click and edit in the designerinterface? Another critique is that even when you know what to do, your workflow gets abruptted by having to constantly shift hands between keyboard and mouse.

To Netbeans defence i must say that I am used to using Eclipse, and changing to another IDE is in it self a frustrating experience. Whats the shortcut for blah, where do I set this. And its quite possible that I just didn’t know enough about Netbeans structure and shortcuts to feel at home.

Credit goes out to : openclipart.org for the image of the phone and dialabc for the soundfiles.

image from the museum.

From the leaflet: “Welcome as a patient to the Psychiatric Hospital”
About the Psychiatric Hospital

The highly regarded Copenhagen architect, Gotlieb Bindsboll, built the Jyske Asylum in the middle of the 19th Century. The inspiration for the building, with its crow step gables and many beautiful courtrooms, was taken from the typical Danish manor houses. Its position, with views over the Århus bay was in keeping with the contemporary view of the healing benefits of beauty. The hospital became known as a model institution for the treatment of the mentally ill, also on a European scale. The first part of the hospital was completed in 1852 and it was extended several times over the next fifty years.

The phone is from 1951 1955 and the “electronics” looks aged but in surprisingly good condition. My first plan for it were to gut it, and put a more modern telephone inside, so I could use it for voip. But when I saw that it were in good condition, I thought it would be a shame to kill it entirely.

So I wanted to see whether it would be possible to use it as it is.

For the voip connection i have a PAP2T linksys adaptor (pap), its quite simple to work with. Plug in power and ethernet cable and configure it with a voip service-provider. Initially I used a normal phone to make sure that i had a working setup, before trying to get the rotary phone to work. The normal phone were quite easy to setup and it “just works”.

For the rotary phone there is still some difficulties. But i have managed to get something to work, and I am working on the rest.

First of all i had to change to paps power output to maximum, else it wouldn’t ring the bells. I am still in the process of fiddling with settings for impedance and/or input gain. The problem is that the microphone volume is very low, and if I just turn the input gain up it turns up for the noise as well. It isn’t a problem for me as i have a crisp and clear sound, but apparently it’s a pain to whomever I am talking to. So something has to be done.

Then there is the dialing. A rotary phone dials by using pulse dialing, which in essence means that it disconnects/hangs up, in short intervals as a method of counting the numbers. But any modern voip-adaptor (at least a cheap one) can only function using DTMF. That’s were sending different tones means different numbers. Which basically means that it is enough to send the correct sequence of tones into the microphone in order to dial a number.

I had seen some applets for dialling they did work with the modern telephone, but the rotary phone with its microphone troubles had to get something more. I had success using “DTMF-dial” (from the ubuntu repositories), because it was possible to tweak the duration of tones and pauses.

Next step, as holding the phone to the PC-speaker every time i need to make a phone call, is not an option, were to make a midlet, that’s a mobile applet. A java program for the mobile. Using the mobile as a dialer may seem awkward, but it already holds all my contacts and the voip is a great deal cheaper. I have a midlet at the moment that is at the proof of concept stage. It can dial and I am able to take a number from my address-book dial it using DTMF. It still needs a bit of polishing, but its mostly cosmetic, maybe a list of recent calls would be a nice feature to implement.

soon to come:

• Nice pictures of the phone, and the electronics.
• Some software for DTMF dialing on the mobile and a bit about devolping a simple mobile application in netbeans.

So I started hacking away. Unfortunately I don’t have any nice video or sound clip, but then again its more like a noisemaker and its just a mess of wires. I’ll try to get something up soon.

But it does work, you have to take my word for it or download the sourcecode and wire up your arduino and try it out.

How does it work ?

There a two modes of operation “play mode” or “sequencing mode”, and it shift between modes by clicking the middelbutton (mousewheel button) and it starts out in sequence mode.

sequencing mode

• moving the mouse changes the frequency of the sound. It’s very simple the more you move, the more it changes (just by (X + Y) *magic_number)
• pressing the right mouse button reduces the duration of the sound
• pressing the left mouse button increases the duration
• turning the mousewheel selects a tone in the sequence, either an existing or adds a new one to the sequence.

play mode

• it plays the sequence of tones you’ve recorded.
• the mouse wheel changes the playback speed.

So it keeps track of both a duration and a frequency, it uses a queue and its possible to add sounds to both ends. I haven’t yet hit a maximum but since its in a int array my guess is that it should be able to hold a lot 100 or 1000 of tones. And it should be possible to do some bytepacking to reduce the memory requirements, but since you have to enter each sound manually and there are no persistent storage you really don’t need that to hold a lot of tones.

Sound Sequencing Mouse sourcecode

It was a matter of connecting 4 wires and uploading the code to get it running. But then i found out that there wasn’t support for the mouse-wheel, so i googled the datasheet for the IC, and started hacking. I ended up getting the mousewheel to function and getting output for the buttons. Along the way I refactored some of code, in order to better understand what was happening.

I still haven’t figured out what I should use the mouse for, but it was a fun hack.

Here is the sourcecode, if you want to try something with it : ps2mouse for arduino

I tried to make nice comments so it should be very straightforward to work with. As mentioned a haven’t made most of the code, just some additions and refactoring.

The mouse and the annoying encoder i couldn’t build a circuit for. It can be attached to a motor where there are a slotted wheel.

(21 nov updated code)

]]> http://rotand.dk/2007/11/21/arduino-ps2-mouse/feed/ 3 http://rotand.dk/2007/06/27/freevibes/ http://rotand.dk/2007/06/27/freevibes/#comments Wed, 27 Jun 2007 11:57:33 +0000 http://rotand.dk/blog/2007/06/27/freevibes/ Finally the summer-holiday arrived, now its time to do some fun coding.

I bought myself a new mobile, a Nokia 6300, it’s got all the bells and whistles. Hmm well at least those I could afford. I choose this mobile because it has : Java, mp3 -player, bluetooth and memorycard.

• specifications from nokia
• review from mobilereview.com

I must admit that i might be a bit of a nerd, so I just had to code something for it. And after “hello world” I found a small and some would say useless application to code.

FreeVibes

I must say I got inspired by vibelet and the article in wired ( Hold the Phone, It’s a Sex Toy ). As the title suggest, its well vibrating. I think that vibelet – though i haven’t seen their program, must be making quite an profit. Because getting a java-enabled phone to vibrate constantly, is quite easy.

So now its Time for FreeVibes, a free software version.

That’s the fancy splash screen	And when its in vibrating mode, this little duck is there. And now why a rubberduck ? ( answers )

If you want to try it out, here are the jar and jad files. Just put them on your java-enabled mobile phone. I have just tested it on my telephone, It should work on any new mobile (with java) :

Jad File
Jar File
Source code

Installation

1. Download the jar and jad file and place them on the phone in the same directory.
2. Run the applet
3. Have fun

Technicalities

Getting things to work with ubuntu feisty fawn.

I use SUNs java 6 and the wireless toolkit for the J2me.

Nokia has a nice area with information about coding for their phones (forum.nokia.com). But i didn’t have any success using their eclipse plugin and carbide.j seems to be a windows application. But eclipseME worked like a charm.

When setting up a device for EclipseME i had to make sure that it was MIDP 2.0 and CLDC 1.1. It wasn’t the default and the Nokia 6300 can’t handle MIDP 2.1.

They code and design is inspired by Nokias tutorial on making MIDP 2.0 games.

The images I used are from the openclipart collection, hacked together with GiMP and Inkscape, and I use obexftp to transfer the files to the phone.