Here are the final projects from “Sketching with Hardware”  in the winter term 2010/11.

Coffee Timer

Verena Lerch and Frederik Brudy

What is it?
In every office around the globe there is the same problem every day over and over again: People try working hard and every once in a while they need a break. So why not go for a coffee with their colleagues and catch up with the latest office information. So usually you open up your e-mail program, send a quick note and wait for reply from your co-workers. Soon, you will get about ten or fifteen replies from your colleagues, every single one with a different opinion about what the perfect timing would be. Often it really gets annoying and coffee-break-mails tend to be treated as spam messages. If one finally manages to find the perfect timing so everyone is happy soon you realize that at least one colleague has been left out of the mail and all the timing stuff starts all over again. Lots of precious working time is lost.This is where our CoffeeTimer kicks in: It is a fast and easy way to time your coffee break. CoffeeTimer saves time and stops the annoyance of finding the right timing to have a break and catch up in an unstressed atmosphere.

How does it work?
A little device is placed on each colleagues table. For every colleague there is a little puppet in in the deviceís body. As soon as you are ready for some coffee you place your cup on top of the globe. It recognizes your cup and automatically transmits your standby to your colleagues. At your co-workers machine the doll representing yourself pops out and signalizes your readiness. The same happens at your place if one of your colleagues comes online in the system. In that way you do not have to ask around who might be available for coffee, instead it is a self-regulating system. The time-finding mechanism is similar to an egg-timer: As soon as you want to initiate a coffee meeting you turn your cup to the desired position and push it down like a button. The timer gets synchronized on every device in the office and the countdown begins. The puppet representing you on all devices lights up, signaling that you are attending the coffee meeting at the given time.If one of your colleagues wants to join in on some coffee he can push down his own cup as well and his puppet lights up as well on all devices, signaling that he is in on the coffee. If the desired timing does not suit your co-workers they can reset the countdown to a different time, which immediately gets synchronized across all devices. Again everyone can join in on the meeting or push their cup again another time to leave the appointment.

Coffee Timer

Values and Potentials
With the CoffeeTimer there is a great reduction of the overhead usually included in the organization of a coffee meeting. The annoyance of ongoing mass-mails in the office is gone. Moreover no colleague will feel offended because he has been forgotten in the mail: Everyone can easily join in on the meeting. Furthermore it encourages all personnel to more office conversations in a relaxed atmosphere, which will help to maintain a relaxed work environment. It is a fun way to plan a break.

Next steps
We implemented group coffee meetings, but private are not yet possible. There is a private-meeting-button on each puppet, which will initiate a private coffee break with he selected colleague.
The CoffeeTimer works well in small office environments. Next steps would include scaling it to more colleagues, since new ways need to be thought of for the puppets if there are more than ten or so co-workers.The device needs to get more compact. Right now not all components are in the globe because of space issues. This can easily be solved by using printed circuit boards instead of breadboards.

Interactive Wardrobe

Anna Follmann | Beatrix Vad,

What is it?
In our project we developed an Interactive Wardrobe. Imagine an ordinary wardrobe, but with additional communication features and integrated enhanced light design. Users can record audio messages for currently absent people and the wardrobe plays the message as soon as the returning person hangs up his / her jacket. In addition the light design visualizes the current state of the wardrobe, e.g. left messages are indicated by colored lights.

How does it work?
The interactive wardrobe distinguishes between four different user interactions: Hanging up a piece of clothing, taking away a piece of clothing, recording a message and playing a message. If a user hangs up a piece of clothing he thereby switches on a white indirect light above the chosen hook. The more hooks are occupied the brighter the light of the wardrobe. If a user leaves the house and takes away the piece of clothing, the light above the hook slowly fades out. If a user wants to leave a message for another person he needs to press the button above the respective hook and hold it down while recording. A colored light above the hook is turned on automatically to indicate the left message. A left message is automatically played as soon as the respective hook notices an event like hanging up or taking away a piece of clothing. Afterwards according to the event, the light above the hook either turns white or slowly fades out.

Interactive Wardrobe Inner Life
Interactive Wardrobe

Behind the design of our Interactive wardrobe you can find two Arduino Duemilanove. One controls the input of the user – which means all button events – and the audio recorder/player units, the other one controls 5 RGB-LED-stripes for the light visualization. Both Arduinos communicate by the Serial communication. The audio units to record and play audio messages are components that are normally used in speaking greeting cards. To manage the amount of buttons, LEDs and audio units, we used two multiplexers. To manage the fact that the audio units have a separate power supply we used one opto-coupler per audio unit.

LED circuit

We programmed each Arduino separately, which means we could operate on two independent modules. If you are interested in the code please click here for the LED-code or click here for the Button-code.

Values and Potentials
The central value of the Interactive Wardrobe is that the communication happens in a very casual way. Messages can be exchanged en passant. The ambient information visualization of the light design is discreet and still holds additional information for the users if they care.

For whom is it?
The Interactive Wardrobe has a wide focus group. It can be installed wherever you normally need a wardrobe. It is useful for leaving messages to others e.g in family households, small offices or shared apartments. The light design could be adapted to fit into the design of the surrounding.

Next steps
In its current state, the Interactive Wardrobe can not identify the person that hangs up a piece of clothing. Therefore the users have to recognize which hook belongs to whom and use only their specified hook. In a next step the wardrobe could be enhanced by adding intelligent detection features to identify the approaching person and play the correct message. Additionally, we thought about a feature called “Buzz”. By pushing a button at the wardrobe a user can buzz another person which creates a haptic feedback (vibration or similar stimulation) in the jacket of the buzzed one.

Spare Time Manager

Verena Hillgaertner and Bernhard Hering



What is it?

Our project was the idea of designing a Spare Time Manager. It’s an new, interactive way to coordinate your leisure time with your friends. You only have to choose your three favorite spare time activities, the start and ending time which is best for you, also your friends you want to spend them with. Those friends will have to do the same, and after a short time, the Free Time Manager will calculate the time and activity, witch suits all friends best.

All this without any complex user interface, you just have to handle everyday life objects, everything is self explaining.

How does it work?

Let’s say there are four friends and everyone got a Spare Time Manager table. Friend 1 wants to spend the evening with his friends, but they never can reach an agreement on what to do. So he uses the Spare Time Manager, because this table always calculates fairly the average opinion of all friends. In Mode 1 he can chooses three of his favorite activities out of the seven possibilities, symbolized by small objects. This objects can be scanned by the machine. Same procedure with the friends he wants to spend time with, symbolized by little pictures of them. At last he has to set the start and ending time which would be best for him on the two little orange clocks on the left.

Then he is ready and sends his request to the chosen fiends by pushing the button on the motorcycle. The machine is now in Mode 2, waiting for the friends to answer.

Now Friend 2, Friend 3 and Friend 4 receive the request on their Spare Time Manager table, the blue light is blinking. They’ll have to do the same as Friend 1, scan activities, scan friends and adjust the starting and ending time. After that he also pushes the button to send the settings. Just like the table of Friend 1, the table of the others are in Mode 2, waiting for the final result.

Finally, when the machine got the average of all friends input, it shows the result by  the different hight of the three orbs hanging in the middle of the table. In Mode 3 the four friends can now identify which of the three highest rated activities has won by checking which orb is hanging the highest. On the little display on the right they can read for which activity which orb stand. Also, they know the average best fitting starting time by looking at the little watch on the motorcycle.

The technology behind the Free Time Manager is based on a Arduino Mega. The Objects are scanned via RFID, the three orbs are moved by three servos. To read the clocks we used two transistors, also the motorcycle alarm was completely rebuild so it could display the finial starting time and manage to though the different modi by clicking on it. For the illumination we used three RGB LED lights who can be controlled separately.

And, of course, we used a LOT of wire 😉

Circuit of Spare Time Manager, just before we built it under the table.
Circuit of Spare Time Manager, just before we built it under the table.

We use a arduino sketch to control the table. The arduino is communication with an processing scetch over the serial port of the arduino. To now the processing sketch is simulation all other tables, but you can implement Facebook Connect, or build an own server Infrastructur for your purpose.

You can get the hole code here.

For whom is it?

The Spare Time Manager is especially designed for people, who aren’t very experienced with modern technology or maybe are just seeking for a new fun way to interact with other persons. Even if you’ve never operated with a computer, it’s very easy to work with the Spare Time Manager, because you’ve only  to deal with things of your normal life, like a fork, a glass or a dice.

On the other hand, young people, who got bored of just clicking on facebook or doodle events on their PC, can experienced a totally new way of planing their leisure time, additionally having a lot of fun and entertainment!

Next Steps

Because the lack of time we could only build one prototype of the table. In the next step we would build more of these tables an actually test them with random persons to analyze if the Free Time Manager really helps them planing their time the way we thought.

Furthermore the table could be build in a much smaller and solid design so it would additionally improve everyone home.

The Interactive Doormat

Chadly Marouane (
Johannes Preis (

What is it?
In our project, we present an ìinteractive doormatî. The main purpose of the mat is to enhance the experience when entering ones home. This is accomplished by letting the users enter a personal symbol combination on the mat with their feet while providing visual feedback on a back-illuminated display. Upon recognizing a user via the entered symbol combination, user specific feedback is provided (here: playing the users favorite song). In an alternative mode, the mat is used as a controller for a little memory game (similar to ìSimon Saysî).

How does it work?
In the standard scenario, the user has to enter a symbol combination on the mat. The user specific combinations and favorite songs have afore been stored in the software. When a known combination is entered, the favorite song of the user is played. Recognizing and processing user input works as follows: The lower side of the mat consists of four seperate areas covered with conducting copper foil. In combination with four wires connected to the foil, these areas form the sense pins of a QT140 capacity sensor:

Test circuit for the QT140

Stepping on one of the four areas causes the sensor to register a change in capacity, causing it to send a HIGH signal on the respective output pin. The output pins are connected to an Arduino Uno which constantly listens for a HIGH signal (when the software is in input mode). When the Arduino receives a signal on one of the four pins, the software takes care of playing a specific sound, and controlling the four RGB-LED stripes. Due to the limited number of digital pins on an Arduino Uno, we had to use a 4-Bit Multiplexer to adress 12 outputs (4 LED stripes, 3 colors each).

Arduino, 4-MUX, LED stripes

In our secnario, symbol combinations consist of a maximum of four symbols. When four symbols where entered, the software checks whether the combination matches one of the predefined combinations and the respective music track is played.In game mode, the software generates a random four-digit symbol combination which is displayed on the screen. The user then has to reproduce this combination using the mat. Upon correct input, a jingle is played and special visual feedback is given on the display.

For whom is it?
The Interactive Doormat is designed for student flat shares or generally living communities with comparatively younger members, since the user distinction by symbol combinations is only meaningful when more than one person is involved. The game mode could either be used as a gimmick for parties (see the youtube video) or for families with young children.

Next steps
In its current state, the Interactive Doormat only plays a specific song when a symbol combination was recognized. Besides obvious improvents like allowing larger than four-digit combinations, further upgrades of the mat could incorporate more user specific output, such as showing the number of unread phone/email messages, user defined rss feeds or even switching on room lights or the computer. Thereby, the target group for the mat could be expanded. Another possible addition would be the use of pressure sensitive sensors for the four mat areas. Being able to detect not only which symbol was tapped but also with how much force could possibly be used for some kind of door unlocking mechanism via the mat.

Final Setup

The software for this project was written entirely in Processing. Communication with the Arduino Uno is realized with Standard Firmata.

Lego Alarm Clock

Kyung-Jin Park (kj.park(a)
Lorenz Schauer (l_schauer(a)

What is it ?

Our project we are going to present is an alarm clock with LEGO. When the alarm goes on one of the lights starts to blink and it shows on which color bricks you have to plug in the white LEGO bricks (you can find them on the right side). With the nose you can change the display (if it’s on or off). To switch-off the light, the sound and the spray (which has a awkward scent) you have to plug LEGO bricks on the right colors. If you do so the light, the spray and the sound goes off and a little hook on the left side gives you a sign that you’ve done right.

How does it work?

Behind the design of our Lego Alarm Clock you can find a Arduino Uno which manages the display, the timer and the two Lego circuits. We used only two breadboards to install all of the electronic components. The Sound of the alarm clock comes from a separate speaker which can be controlled by the arduino via a opto-coupler. Two servos were installed to move the flag and to spray a fragrance of lemon while the alarm is ringing. Every day, the arduino switches the Lego circuit from one to the other, so you cannot set the same cicuit every day.
We programmed the arduino with the proper language of arduino. If you are interested in the code please click here for more details.

For whom is it?

The LEGO alarm clock is designed for kids and youths to make it amusing to get up. The colorful body of the clock is very child-friendly and it has some gimmicks: The lights represent the eyes, the display the mouth, and the nose (which you can rotate) gives the kid some more playful impulses. It has also a bin for the white bricks and a flag with a note ‘Good morning’ and ‘have a nice day’ so the kid can start their day easily.

Next Steps

There are plenty of ideas you could upgrade the alarm clock. You can build a radio and a volume control which you can navigate by lego bricks. You also can make more funnier and more confusing circuits so the kids have to play with the bricks a bit longer. You can make everything tinier or prettier and more compact. For a common interaction with generall alarm clock features, like to set the timer or to change the display’s time, it is necessary to install some extra buttons. But you can also use an old alarm clock and hack it, like the way we do it in Sketching with Hardware.

You can make anything which would make fun for the kids because kids enjoy playing.
So the prototype of our Lego Alarm Clock is just the begin of a new generation of funny alarm clocks…


Robert Rödler and Maraike Stuffler

What is it?
In our globalized world it has become very usual to have a long-distance relationship. Of course two people living far away from each other miss physical contact, or can’t even fall asleep without the other one. Indeed they are able to see each other via webcam, but they have no options to snuggle or hug, because personal computers aren’t very cuddly. They also could talk on the phone, but at the cost of their facial expression, which makes communication – in particular emotional communication – difficult. We worked out a solution for that missing part: “Robocat”, a soft toy, which you can take with you and snuggle with when you’re going to sleep, which can be used to communicate to the other person just by playing with it, and which shows you the mood of the other person. Robocat brings haptic and audible fun in long-distance relationships and banishs loneliness!

How does it work?
Each person has their own Robocat at home which is connected to the Internet. But both Robocats act and must be seen as one representation of the same cat. When you come home, you place a key pendant with the shape of a mouse next to your Robocat. The eyes of your partner’s Robocat will now begin to glow, indicating that you are at home. If you are happy then give your Robocat a little ball of wool to play with, it will change its facial expression depending of both of the partner’s moods. If both are happy, then their Robocat smiles, if both are sad, their Robocat also looks sad, and if one is happy and the other one is sad, then Robocat will look neutral. This makes it easy to find out in which mood your partner is at the moment. If you want to cheer up your partner or just let him or her know that you want to cuddle with him or her then fondle Robocat’s back: Both Robocats will begin to purr! If you somehow want to get attention, just press the cat’s paw and both Robocats will start meowing loudly.
If you are angry and want to let your partner know, pull Robocat’s tail and both Robocats will begin to hiss.
Robocat is realized with two arduino duemilanove, which control the input and output of both cats.
With the following code for Processing we check which pin has an input signal and play the related sound:

for (int i = 0; i <= 5; i++) {
if (arduino.digitalRead(i) == Arduino.LOW) {
if (i == strokePin) { playSound(1); }
if (i == tailPin) { playSound(2); }

It has LED-eyes, the mouth and the eyebrows move with the help of three servomotors and a linkage. The key pendant and the ball of wool work with magnet switches. In Robocat’s paw is also a normal press switch. The tail contains a elastic strap which is connected to a rebuilt press switch. The highlight is the ability to fondle Robocat’s back, which works with a capazitive sensor.

Values and Potentials
Robocat makes haptic communication possible, and not just for partners in long-distance relationships. It can be used in many situations, for example as a toy for young friends, since highly technologized toys has become typical fare in industrial countries. But Robocat also offers new possibilities to commuting parents, who want to put their children to bed. Of course Robocat could also be used by retired persons, who aren’t able to move themselves much. Robocats big advantages are its interactivity, the haptic way to communicate and its cuteness.

Next steps
At the moment, all the wires, arduinos and other technical stuff don’t fit into Robocat’s body. This can be solved by using printed circuit boards and would be the first aim to reach. Then a second cat would be needed, we just finished one cat and simulated the other one by software. It also would be a great enhancement, if the cat was wireless and could really communicate via Internet. Another option for Robocat would be to add in the Skype-functionality. Then you not just could snuggle with someone, you also could speak with him or her at the same time without going to the personal computer. Furthermore we could make the cat more interactive, if we built in haptic feedback or a movable arm, so that Robocat would be able to “hug back”.

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