How to make circuits with a Roland CAMM sign cutter

I prefer to solder the circuit while on still on it’s original backing as the thin fabrics I use melt very easy.

For a project at the V2_lab we had to develop a transparent touchpad in textile. For this we needed to create circuit boards that are thin, small, easy to mount on a textile substrate and more or less flexible. To create such a circuit board we started to experiment with cutting copper foil on the CAMM-1 at Protospace fablab.

Design

The cutting of circuits in copper foil turns out to be very doable but some extra care when designing the board is needed.

No vias

This speaks for itself. A work around is to use WireWrap wire to make wire bridges.

Corners should be rounded

Copper foil does not stretch as the vinyl does. Because of this if the corners are too sharp it is possible the rotation of the knife lifts the copper from its backing. This might cause problems if you have dense packaging and/or small traces.

Minimal 0.6 mm space (degrades quickly when blade gets blunt)

After some experimentation we found that the minimal space between cuts is ~0.7 to 0.6 mm. This can be lifted a bit as long as the amount of cuts is limited and cutting speed is very slow. This also depends on the foil brand, sharpness of the knife, knife force etc.. It is good practice to cut a test before cutting the rest to fine tune the settings.

On above picture it is very clear what happens if spacing is too small.

Don’t do tight packaging

If the circuit board needs to be flexible don’t package the components too tightly. The solder joints are the most susceptible to mechanical stress. If the traces are longer they can take much of the stress away that would otherwise work on the joints.

Component sizes

As far as component sizes concern anything smaller than 0805 and SOIC would be pushing it. Even if it can be cut soldering it will be practically impossible as the traces are able to move. We used 1205 packages to be on the safe side; there is enough space for a bit of movement.

We did our board design in CadSoft Eagle and exported as a bitmap with all layers turned off except Top, Pads en tStop.

Board design

The bitmap was then imported into Adobe Illustrator, scaled to its actual size (this has to be done very accurately) and paths drawn over the traces. It is now very easy to adjust the sizes, round the cornes and do some more tweaking that might need to be done. Only keep in mind that the pad distances stay the same and are accurately aligned. The last step is to outline all paths (Object -> Path -> Outline stroke) and merge all shapes that form a single path using the Pathfinder’s ‘add to shape area’ tool. Inversely to create holes use the ‘subtract from shape area’ tool.

Board outline ready to be cut.

Cutting

For cutting the circuit we use Cutronic copper foil (http://fablab.waag.org/content/techsoft). This is an A4 size copper foil with an adhesive backlayer. It is specially made for this type of usage (although they don’t advise to do SMT with it ;-) ). Cutting the foil needs some different settings of the CAMM-1.

Pen Force

Should be set somewhere between 60 to 80 gf. This also depends on the shape the knife is in and the type of foil used. Experimet with the build in test pattern before proceeding. Cuts should be well through the foil but only make a little schratch in the backing. If it cuts through the backing force is way too high. If it does not scratch the backing sometimes it won’t cut through the foil meaning more rework afterwards.

Speed

This should be set to quite a low value, 1cm/s is the slowest and recommended for complicated designs with tight packing. It also gives some time to push back little pieces that came loose with some fine tweezers.

Blade

The amount the blade should stick out depends on the foil used. For the Cutronic foil somewhere near ~1mm gives good results. It is recommended to use the original Roland blades as they are expensive but harder than the cheaper blades and will last longer. The blade originally supplied with the CAMM-1, the ZEC-A1005, is quite suitable for cutting copper foil. See the attached pdf for an overview of CAMM-1 blades.

A cutout circuit board, left ready to be soldered (after tidying the little corner on the left), right as it comes out of the CAMM-1.

Soldering

First thing to do is peel of the excess copper so only the circuit itself is on the backing paper. Soldering can be done while the circuit is still on the paper, it will get a bit yellowish but won’t burn or melt. One thing to watch out for is the glue loosing adhesive strength when heated (it will stick like before when cooled down). This can make soldering a bit tricky. Loose pads will try to stick onto the soldering iron so great care and thinking about soldering order is needed. Also a set of very fine (SMT) tweezers which are anti-magnetic is a must. When all that is kept in mind, with a bit of practice, soldering on the foil is surprisingly easy.

Finished board (black blobs are carbonized glue, grey wires are conductive threads)

Some components which have very tiny leads (like SOD diodes) will have to be reinforced as the leads will break from the package under stress. We used some drops of polyurethane glue to do the job (the blobs on the left and right in above picture). Only use small drops as it will expand.

With a little penknife, tweezers and care it is fairly easy to remove the circuit as a whole from its backing. Carefully slide the knife under the circuit bit by bit while holding it with the tweezers until the whole circuit comes off. The circuit can now be stuck on something else; textile in our case (see for example our first flexible circuit on felt test)

End result

The end result was a transparent flexible touchpad. The circuits have been connected using conductive thread and carbonized glue.

Almost finished touchpad

Due to the limitations mentioned above we could not cut the A/D board as the A/D chip has a TSOP-16 outline which is too small to cut. As a compromise we etched it on a very thin epoxy board.

An experiment making a two pixel display using a sheet of liquid crystal thermochromatic ink and nichrome wire.

The pixels are controlled independent from each other and switched consecutively. The total current drawn is approximately 80mA independent on the number of pixels.

The metal ring on the left is there just to keep the autofocus of the camera focused.

Posted from JoSoS on Flickr: Thermochromatic two pixel display

The Tweet Bubble Series consists of four wearable speech bubble prototypes developed in collaboration between artist Aram Bartholl and V2_Lab.

All four prototypes reflect on the micro blogging service ‘Twitter’; a relatively new Web2.0 platform that fills up the gap between blogging, instant messaging, and SMS. All messages posted on Twitter are public by default and stored as single HTML pages. Due to Twitter’s growing success, the platform is about to become a standard communication tool. The way in which Twitter is used to communicate within a social network is largely shaped by the absence of physical proximity between users and the relative anonymous social exchange that the platform allows. To deeper investigate into the role of this absence of physical proximity and relative anonymous exchange in the use of Twitter, the central question to the wearable speech bubble prototypes is: What would it be like to not only show your latest message online, but to also publicly display it on your T-shirt?

Pocket Tweets – A Cell phone display enabled Twitter shirt for everyday use.
Pocket Tweets makes use of existing technology by activating the mobile phone every user brings along anyway. A small Java application is offered for download to be installed on an internet activated cell phone. After the user inserts his/her Twitter screen name the application receives the latest tweet and displays the message in a white speech bubble on black background. The idea is then to wear the phone in a custom designed pocket on a shirt, jacket or bag. A speech bubble shaped cut out in the cloth shows the displayed message to the public in a subtle way. The ubiquitous mobile phone turns an everyday life shirt into wearable technology. The private screen of the mobile phone points to the public.

Loud Tweets – A LED name badge hacked into a personal Twitter feed scroll ad.
Loud Tweets instead introduces its own technology. LED name badges are a new, low cost product series made in China which refer to the classic LED bar display. Scrolling text on red LED bars represents a very typical and specific culture of advertisement. It attracts a lot of attention and they are used in any kind of public space: from shopping to public transport.

The small 21×7 pixel, red LED name badge can be programmed by three buttons to display 255 characters as a scrolling message. Through a GSM connected Arduino board the display receives the latest Twitter message of the user. Loud Tweets is a custom made standalone device of fairly low cost and hacked components. The attention culture of Twitter and the cheapness of LED combine into a personal micro adverstisement sign for public space.

Paper Tweets – Twitter messages printed on stickers for event crowds.
In contrary to Pocket Tweets and Loud Tweets which are designed to experiment in everyday life public space Sticky Tweets does work as a conference intervention ideal for big web related events. Conference visitors are invited to wear speech bubble stickers with their own latest Twitter message on their clothing to engage real life / virtual identity – cross communication. First participants have to register at the Sticky Tweets desk with their Twitter screen name. In return they receive a blank speech bubble including a RFID tag. The user gets regularly updates of his/her own twitter messages throughout the whole conference area. A mobile team equipped with RFID scanners and label writer prints the individual current message of each registered user in real time on the spot. The relation between digital and printed feed combined with the chase for the actual message leads to an absurd play of interaction. The ephemeral nature of Twitter posts is subverted by paper based communication.

Classic Tweets – Standard claims sewn into thermo chromatic enabled T-shirts.
Classic Tweets incorporates a novel technology to use a T-shirt as a display: A conductive wire is sewn into a thermo-chromatic T-shirt. When the conductive wire is heated up by electricity, then the shirt’s thermochromatic ink turns white around the wire. The three most typical Twitter messages are sewn into the Classic Tweets T-shirt and can be separately ‘lit up’ by the user. This allows a user to individually twitter these three messages, depending on the activity s/he engages in.
“Having coffee.” or “Looking at …” (a specific website) represents a large amount of daily posted tweets. The presence and the need to share the moment are the momentum of the service. The repetitive character of every day life is condensed into the Classic Tweets T-shirt.

The Tweet Bubble Series has been developed as part of the ‘Wearable Technology’ artist-in-residence program at V2_ Lab in Rotterdam during the spring of 2009.

V2_Lab project team: Piem Wirtz and Simon de Bakker

Artist: Aram Bartholl

After the workshop introduction and meeting round participants were split up into two groups to distribute the wide variety of skills. The background of participants was broad (ranging from industrial designers to fashion designers to hard- and software developers). As the average knowledge of the participants was quite high, the goal of the workshop was ambitious: create a performative sound experiment.

Kobakant showed many examples of their work and provided the right atmosphere for a long day of discussion on the yet-to-be created pieces. Near the end of the day both groups had a clear idea on the theme, sounds, looks and performance they wanted to create.

The second day was the day of hard labour. This day the ideas of the 1st day had to be put into wearable garments using conductive threads and textiles, hacked toys which Kobakant brought, Lillypads and self made sensors. During the day it became apparent that the two groups had taken very different directions.

First group developed into the direction of a modern dance performance in which contact improvisation was the major theme. The garments were made into a large contact sensor using conductive threads. Different sounds were generated and processed depending on the place and change of human contact.

…..The second group took a direction into poetic, theatrical costumes to explore the ritual of meeting. Generated sounds and a live played cello soundscape were transformed by the meeting ritual. Light sensors in the frays influenced the soundscape, while a self made motion sensor introduced a hint of a modern form of communication.

The results were performed at V2_ during Test_Lab: Fashionable Technology.

Finished my wireless RFID set, from left to right:

• Desk reader/writer (non-wireless)
• Receiver (receives the IDs send by the transmitter
• Transmitter (reads and immediately sends RFID tags over a 433MHz radio link)

touchpad internals

The prototype touchpad has 8 sensitive areas roughly the size of a man’s hand. All areas are embedded in a single layer of metallic silk organza. Only a light touch of one or more of the sensitive areas is enough to trigger. In total the pad has five layers (might increase to seven depending on the possible addition of a ground ‘plane’).

• organza sensitive layer
• two isolation layers (could be one depending on fabric quality)
• component layer
• two isolation layer (could be one depending on fabric quality and presence of ground plane)
• possible ground plane

The sensing boards are constructed out of copper foil circuit boards (cut with a Roland CAMM-1 vinyl cutter at Protospace fablab Utrecht ) and conductive thread. They work by capacitively coupling a relatively high frequency signal put on the metallic organza sense areas. On the left is the A/D converter board (unfortunately TSOP-16 is too small for cutting).

In the movie I overlayed (slightly out of sync) the touchpad output as a bar graph. Only the first 4 (out of 8) outputs are functional in this test (the most left bars in the graph).

Continued development on the organza soft touchpad.

The basics are working with the CCB’s in place. Much of the electronics (bottom in picture) will be embedded as well in the next generation.

Posted from JoSoS on Flickr: Organza touchpad development

The consequence is that JoSoS had to move and my choice is to host it at wordpress.com… so here we are.

The old JoSoS can still be found at http://www.void7.org/~simon/josos. This location will be removed somewhere near the end of January so please update your bookmarks, links or whatsoever especially if you are looking for MidiPy or bluespam …

A CCB (Cutout(tm) circuit board) on a felt carrier.

This is a first try-out of using felt and CCBs. After cutting out the circuit it is stuck on a piece of felt. Hopefully the next version will look a bit more tidy.

The knit thing on the right is a knitted pressure sensor knitted on a knitting machine by colleague Piem. Notice how the LED blinks faster when the pressure increases.

Posted from JoSoS on Flickr: Felt Circuit Board

The first prototype of the Metallic Organza Touchpad I am currently working on. The prototype only has two sensitive areas but this will be increased quite a bunched over time. Also it will be using the CCB (Cutout Circuit Board) as described in the previous post.

Posted from JoSoS on Flickr: Prototype organza touchpad

Since short we have been experimenting with cutting out circuit boards out of copper foil using a vinyl cutter at protospace FabLab. First attempts were with moderate success but fine tuning the cutting settings and adjusting circuit board design the results can be said to be quite OK.

Posted from JoSoS on Flickr: Prototype organza touchpad

V2_ workshop at eARTS Shanghai led by invited artists Aram Bartholl and Daan Roosegaarde, and supported by Simon de Bakker (me) en Michel van Dartel of the V2_Lab. I was there to give the basic electronics and arduino introduction and to help the students to get their works working.

V2_ workshop description
eArts workshop announcement
Workshop pictures

Depending on the RFID tag a different animation controls the ultra bright Luxeon LED. The LED in the movie is only driven by ~1/4th of it’s maximum power. Go figure :-)

The small LEDs will grow into high power LUXEON LEDs embedded in architectural garments.

PWM signals are controlled by animation data loaded into flash memory.

Saturday and Sunday were the days of the Soft(n)/Hives workshop. Only though we had just two participants the workshop was quite a success. Images captured by the Hives Scouts were tagged and shown based on how the Soft(n) objects were handled. Which worked quite well.

Unfortunately i have have had no time to really attend talks or enjoy the rest of the festival nor go to Undeaf. But well, now it’s time for some relaxing.

Things have finally gotten less freaky.

For now i have reverted back to my old non-preempted kernel compiled with gcc-3.4. No EABI, no real-time. Just plain vanilla. I haven’t had any hangs for over 24 hours now so who knows. It will take me probably quite some time figuring out what actually happens, but as long as we don’t hang now, that can wait until after DEAF07!

For the last week i try to get the soft(n) SIOS/gumstix firmware stable with variable success. The problem is everything hangs every now and then. Not just the application but the whole system. No message nothing, just a silent stop. Now the freaky thing is that this seems to happen only when i whatch at it.

Everything has been running fine for whole night. I have a look, kewl it is still running, great! And then just to drive me crazy it stops. All running fine again, i show it to someone, halt. Again running fine over a very long period of time, trying to take a picture … stop. This is going on for almost week. I’m seriously starting to believe Murphy’s spirit is haunting me…

Hopefully this little writing down, has cast it away…

Last friday, after 2 weeks of hard labor, we finally had the technical user testing of our soft objects (formerly known as pillows) at V2_. For this we had invited three students of the Willem de Kooning Academie in Rotterdam. In three sessions they could do whatever they want with our objects.

We have seen some of them playing football with them and others landing on them out of more or less free fall. Miraculously the objects survived very well. The beep/buzz UFOs that are inside sprung open and one of the WiFi cards got loose. Also one of the cables got pulled out breaking the connector in its going. But these are minor things and can get fixed and prevented.

The students reactions on the objects themselves were quite positive, despite the irritation noises they made (which was a general complaint).

Here, gaseous micro-bubbles injected within a fluid medium are blasted with ultrasound causing them to implode, at which point they become as hot as the sun and release light energy in the form of sound waves. By modulating, or ‘playing’ the ultrasonic transducers attached to the glass chamber an ever-changing sonochemical environment, visible only within a sheath of extreme darkness, emerges. Theories for the cause of the glow from the collapsing bubbles are still the realm of exploratory and to some extent speculative physics ranging in abstract theories from black-body radiation and plasma ionization to quantum vacuum fluctuations. The Camera Lucida: Sonochemical Observatory creates a rare opportunity, as a powerful aural and visual experience, to encounter this volatile phenomenon outside the confines of highly specialized sonochemical laboratories.

The sound waves that are able to cause this effect start somewhere from >20KHz so outside the audible range. In the Sphere is a little piezo microfone that records the soundwaves which are further processed down to the audible spectrum which makes it possible to hear what is going on inside the sphere. A nice effect is a clustering of light patterns around the piezo caused by the piezo resonating at the same frequency as the soundwaves it records.

If in Rotterdam the coming two weeks, go have a look it is quite a special experience.

Today i tried to get the switch chips to work with the gumstix and driver i wrote earlier (see part4) without success. All switches are to stay open! The ones i got are TC9163N instead of TC9163AN may that be the problem (negated inputs or so (hm, i should try that)). Unfortunately i can only find datasheets for AN and not for N.

I still have bypassed the switching and hooked up my speakers just to listen if the sound is ok anyway (only used test signals and headphones until now and square waves don’t make you happy).
Addition i forgot to add yesterday: I also can confirm now that an excessive load has been the cause of all the troubles. It blew the input and record switches. As a result that the CK and DATA lines of the input select have -14V on it. Which blew the CK line of the big fat luxman driver chip, hence the missing clock signal. Fortunately it didn’t seem to cause much more damage. There is one more thing though which i found out yesterday. If i select direct input, the overload protector relay clicks on for a 10 to 20 seconds after which it releases and everything seems fine again. But it indicates some bad somewhere which i need to look into.

Second addition: Just found out i stupidly enough ignored the chip select bits for the switch array. Adding a high for bit 11 did the trick. I uploaded a new and slightly improved driver here: TC9163.

The soldering of the tone board connecter was very bad (see top picture). I wonder how it ever could have worked before??? Resoldering fixed the problem and left and right are both present again.

Now back to the input selection…

• Two fuses blow as soon as record selection circuitry is attached
• The input / record selection is f*cked up
• Somewhere the left channel is chopped off

The input and record selection is build up around two analog switch arrays (TC9163AN) which must have had quite a blast (did i already mention the amp broke because of a _very_ faulty input device?). Replacing both chips solved problem 1. Still the input / record select remains faulty. The right channel is omni-present (comes thru regardles of which input connected to or which input selected) while the left channel does not come thru at all.The TC9163AN uses a 14 bit pattern for switch selection. This pattern is clocked into its shift register. There are 6 data lines going to the input board: DATA, CLK, STIN, STRC, RCT1 and RCT2 (these lines come from a obscurely large Luxman chip on the front panel). At this moment only the DATA, CLK and STIN lines are important (STIN and

STRC work as a kind of chip select). Using the logic analyzer shows that the DATA line is doing what it is supposed to, but… there are _no_ clock pulses! Those pulses are needed to shift the data bits into the register. This could explain why there is no reaction when pressing the buttons. Unfortunately the big luxman chip is as a big black box and is not described in the service manual. Tomorrow i’ll write a little gpio driver and use a gumstix to generate appropriate clock and data signals. If we can get the right behavior we nailed down the problem. Only thing left is a solution.
Until then i bypass the input by directly wiring the CD input to find out where problem 3 occurs.

After some effort i succeeded to access the tone board (a lot of screws and cable ties), the second step after the input board). Using a little pd program (right laptop in top image) to generate two test signals (10KHz and 1KHz semi square waves for right and left respectively) i can now trace down the signals using the 2 channel scope (can’t do without this bitscope thingy already). As it is already quite late i only checked to see if it survives the tone board, which it does (left laptop in top image).

So far for now

Also today my pc based logic analyzer and oscilloscope, a BitScope BS50U pocket version, came in. I’m quite happy now, have wanted such a thing since i was 12 or so. It is a nice piece of equipment for hobby purposes and for persons like me who don’t have that much space to place a 60cm deep analog scope (and not the least important; don’t have the big bucks). The best thing is that it is a complete open hardware design, and the software also runs on linux which is rare with these kind of tools.

This weekend i start repairing and hopefully with success….

Some pictures of the process.

The first part i decided to go for was a vanTuyl frame which i could get cheap because it’s a last years model. They even paint it nice matte black for me. Unfortunately it still has to return from the paintshop so i’ll have to be patient.

But on the good side… today my new wheelset came in. The mavic cosmic elite 05, and they look cool!!. Darn thing is that some days after i ordered them stumbled upon a site where they got some bad user reviews. They also got an equal amount of very positive reviews to though. It looks a bit like there’s an equal amount of getting a good or a bad set… so let’s hope chances are with me. I do have to buy some good rimtape though as they came with some very scary looking plastic ones. I don’t dare to put my tubes between those sharp looking edges.
More will be coming up as soon new parts arrive

Further, to make my training life a bit easier i wrote two little tools. One to compute my training zones according to the karvonen formula based on max hart rate and rest hart rate. The other one lets me see what speed a certain gear ratio and cadence combinaton gives.
Both can be found here.

A description ripped of the presentation inviation should make more clear:

[quote] with affect and desire as our starting point, our methods
of exploration has varied from hacking and re-appropriating
existing technological objects, quick and dirty prototyping,
to development of soft and hardware and formal writing.
through this process we have attempted to realise our
wearable objects of desire…[/quote]

For now i only have urls of two of the projects (i guess the other two have no sites yet)

sonic jacket by Dragana Antic
This one needed an extra driver adjustement for the UCB1400 on the gumstix audiostix board to expose the 10 GPIO ports of this chip. I’ll make a patch available soon (if you can’t wait mail me and you’ll get the dirty one).
Furthermore it uses flac audio codec for real-time encoding of live recorded audio, while decoding at the same time. This all happens on a gumstix basic 400Mhz. (I’ll make the flac gumstix makefiles available soon too. But if in a hurry the same as the driver patch).

fuse by Cheryl Gallaway
This other very cool project made use of a basic stamp, 49 bi-color leds and an infrared transceiver. Although a basic stamp is nice for rapid prototyping, if you have to do critical timing (as was needed for the IR-transceiver) it is no good. As a result of that the fusing of the symbols only worked under very controlled conditions (but horribly slow).

Nice thing is that since linux 2.6.12-rc4 usbnet has a fix for the non-standard usb class specification more info. So no need for the belcarra driver and 2.4 kernel.
Make sure to add:
CONFIG_USB_ACM=m
CONFIG_USB_USBNET=m
to the kernel config.

Next i installed the convenient utils from silvio?, and got nano running: img.

And… compiled my first A780 hello world using the gumstix toolchain: img.

Hoping i’m allowed to fiddle a bit more with it so i can do something usefull.

First problem was that the adm1025 kernel driver was not generating any activity on the i2c pins. This problem was solved with a tiny adjustment to the i2c-pxa bus to let it support hardware monitor class devices.

Now loading the adm1025 driver generated some output but all transmissions resulted into bus errors, so it could not even start probing for the chip…. After staring at the scope output for an hour and wandering through the drivers, figuring why we kept getting those transmission errors, we finally ‘discovered’ we mixed up the sda and scl lines, because we could only use 1 of the scope’s 2 channels this slightly vital stupidity remained hidden to us… duh.
The last step was letting stuff run in i2c fast-mode (default is 100kHz). This only took setting the FM bit in the pxa’s ICR register.

et voila, all done.
patches are here

D-Toren is an interactive architectural piece located in Doetinchem. The color of the tower changes according to the mood of the people in Doetinchem. The mood is measured according to answers on a questionaire created by Qs Serafijn. The tower is created by Lars Spuybroek (NOX). My part in this project was the website backend (dbase, java servlets etc) and hardware interfacing with the tower.

Also see: www.d-toren.info and the webcam (the tower might change color somewhere around 20:00u local time)

So after reading tons of reviews my first choice was the Nikon D70, but after seeing it in meat space it came out much too bulky. My second favourite, the Pentax *ist DS is really much smaller and not less in quality and options and so my new favourite. Some extra advantages against the Nikon D70 is that it uses SD cards instead of CF and the USB2.0 interface actually _is_ USB2.0, which with the size of pictures (~10Mb in RAW) becomes quite significant!

So, next thing is to learn al those photography tricks again.

:-)

See some pictures (my phone’s camera aint a very good one) here.

Had to add a simple GET in order to be able to get device specific information.

It handles “telecom/devinfo.txt” “telecom/pb/info.log” and “telecom/cal/info.log” but should be able to get an arbitrary file of size that can be handled by OBEX_FL_FIT_ONE_PACKET.

There is now also a makefile for the gumstix tree: btopush.mk.

Haven’t been able to try it out on the device though, ’cause i was stupid enough to forget a lousy thing as an american to european convertor ‘blokje’ for the power adaptor.
The Makefile and patch can be found in the misc section.

He also showed these cool sites: darwin@home and biota.org.

“If you want to know me, date me”

evo

Meaning, no heavy duty dull personal life stuff (maybe some events off high value though).

The blog is meant for some geeky things i’m working on or come across. Although i have

been posting a little bit on artm’s blog which has the same purpose, i decided to put up

my own for some more personal geekies. Big things i’ll probably post there as well.

So far for the little introductory,