These sound drops do actually have four sounds but only one is exported to the outside using the big front button. Once opened up you can see four pairs of pads of which one pair is shorted, that is the current sound under the button. The sound is activated by pressing the button which provides the chip with power.

With the pad desoldered you can choose which sound is played by shorting a pair of pads and pressing the button.

For the Mario brick we want to use all four sounds but play them randomly with a weight on the coin sound. To do this I use a 4017 decade counter. When a button is pressed the counter counts with a high frequency (~150KHz). As soon as the button is released the the sound drop is activated with the output the counter stopped on. In order to get the weighting 5 outputs of the counter are joined together and activate the coin sound.

All together the circuit draws 0.1mA of current when idle, 2mA if the button is pressed and 25mA when the sound is played.

Together with one of those cheap wireless doorbells I got myself a nice doorbell :-)

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)