Hardware Hacks: Servo Hacking

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For some reason many people – even computer science students – are originally afraid of unscrewing and opening electrical devices. While it is truly not recommendable while said device is currently under charge I believe it provides a lot of general understanding on how a device works and also enhances the learning process. Things get less abstract when we understand HOW. It makes us think of the WHY and why not to make it better. So put your fears aside and just start to unscrew something. Something not too expensive so you don’t have to worry about messing up too much. Something that will be useful if you unscrew and modify it for example. A Servo for example.

A Servo is some little device that can turn something around, but only to and from a certain angle (ca. 90°). But if you want a Merry-Go-Round you will have to get rid of the block. So they work like this:

 

Here is how to:

First off: There are several versions of servos. Each one more difficult to hack:

  • 100% plastic servos – the easiest to hack
  • Plastic servos with a metal potentiometer – hackable with a small workaround
  • Metal servos: The whole gear-work plus potentiometer are made of metal – if you cannot work an angle grinder, forget it.

I’m going to describe how to hack the first and second one as they are the ones we usually use at Sketching with Hardware.

So let’s get started.

First a little overview of the innards of a servo:

http://www.jameco.com/Jameco/workshop/howitworks/how-servo-motors-work.html

A look inside a servo

If you hack a servo there are basically two things you have to do:

  1. Remove the stopper so the gears can turn 360°. This is usually positioned on the drive gear with the output spline.
  2. Modify the potentiometer – output spline connection so that the potentiometer is fixated but the output spline can still turn.

So now we can start: unscrew the servo. But keep the side with the output spline up. Otherwise the gears may fall out! Don’t worry about the motor and control circuit falling out on the other side. They are fastened really well.

After opening the servo you’ll find an armada of gearwheels. I truly recommend you now make a photo from at least two angles (up and side) so you know how to put it back together – as there are small variations on the gearwheel allocation between the different models. Now look closely at the gearwheels (you have to take them out) one has a plastic plug over some gearwheels. This is the stopper. Use a cutting pliers to remove it.

In some cases there are no gearwheels where the stopper has been. If you are very sure in its use use the bandsaw to add them manually otherwise ask somebody who does or look for a servo that does not require this step!

With the gearwheels now capable of turning 360° we can move to the next step: The potentiometer

Now first a little explanation about how the motor and potentiometer work together: The motor is able to go around infinitely, but is stopped by the potentiometer that can only go 90°. They are connected by gearwheels. The motor drives the gears who are controlled by the potentiometer. The potentiometer can only turn on a 90° radius. On the potentiometer the output spline is mounted. That in turn is the key to turning the servo arms.

What we know now: the motor does not turn the output spline directly, but connects to the gears that do. Unfortunately those gears are connected to the potentiometer with a pin. But we do not want the potentiometer to influence our movements.

The solution is rather easy: you have to drill a hole in the output spline where the potentiometer pin goes in. You basically just drill out the thread (dt. Gewinde). I recommend using a steel drill and it will go through like butter. Also take care not to screw the vice too tight or you damage the gears. Putting some cardboard between the vice and gear helps.

Finally: Fixating the potentiometer

The potentiometer turned to one side gives full power. Turned completely to the other side it turns the power off. Best thing would be to keep it in the middle (or at highest if you require it) to test the current setting you can use an LCR-meter.

You now have to fixate the position of the potentiometer. Otherwise you risk that it moves to the “power-off” state sometime later. For that last step you can try to somehow glue it. With the plastic versions I was very successful using the hot glue gun. Although you risk getting a few minor burns on your fingers while molding it. After applying the hot glue let it cool down. Then cut the protruding hot glue away with a Stanley knife (horizontally, or you draw the glue back out). For the metal  potentiometer the hot glue does not work really well, but I did not have the time for further materials science. If you find something better that hot glue for those, please share and post your results in the comments.

And that’s it. Congratulations! You just hacked a servo.

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Rescute

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Idea

Our brainstorming was very intensive. We examined various factors, especially the items “Good” vs. “Evil”. We associated night, fear and attack with “Evil”. Why we chose a teddy bear is very easy to describe. During our whole brainstorming we always recollected to the teddy bear. It never turns out of our minds. It is the typical toy of everyone’s childhood. Everybody has a relationship to his teddy. It is a typical companion, so we decided to apply our teddy associations as the “Good” aspect for the project.

We thought about situations where we would like to have a special friend with us. Sometimes when it is very late and you have to go home alone you feel very uncomfortable. An attender would be perfect in such a situation.  In the case an attacker follows you or attacks you, your friend the teddy bear includes some rescue levels. Possible features would be an included pepperspray, barking sound, police sound, blue light effects or an emergency call to the police.

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Concept

Our concept is a teddy bear, not too big, which fits in every handbag to carry it with you. We decided to integrate three rescue levels depending on the degree of danger. When you are going home alone in the night and you feel uncomfortable or you are imagining that someone is following you, the first level of the Rescute can be activated. Immediately the bear starts to bark. Thus, the follower will notice you are not alone, he will think you have a dog with you, not knowing that there is far more in your bag. Perhaps the follower is already warned and goes away. If not, you can select the second level. The bear starts to shake his head and its eyes begin to flash in blue. Additionally, there comes police sound out of its body. The bear simulates the police arriving. If this is not discouraging the attacker or he starts attacking you you can select the third and last level of Rescute, the Pepper spray with light effects. This will help you to target perfectly at the aggressors eyes. The third level will give you enough time to run away or to get help.

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How does it work?

First of all, we thought about the connective of our bear, the basis of our levels. Therefore, we remembered of the toys which have an integrated music box, controllable by a trigger line. We want to use this principle for our project. We used a pipe with copper tape. For each level we put two piece of copper tape inside the pipe which are separated from each other. These tapes will be connected by steel wool which connects the two copper tape sides. The wool hangs on a line. This line could be applied by lift pass holder which is fixed on the inner bottom of the bear. It closes the circuit and the effects will be triggered. When someone pulls the line the wool connects two of the tapes and releases the connective effect.

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For the sound effects we used a greeting card sound modul. We tried to build an audio amplifier to multiply the sound but this was not easy. So we put a pipe above the original loud speaker. This improved the volume of the sound with a great difference.

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For the blue eyes we bought white lamps and painted them blue. The shaking head is a servo which is fixed between the shoulders of the bear. The moving part is fixed with plexiglass and hot glue at the head.

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The pepperspray is integrated by a hacked airwick. This airwick starts to spray by getting an electric impulse via piezo ignition. We controlled this impulse by one pin of the arduino. For the audience at the presentation we did not use a pepperspray but a airwick spray.

For the light effect of the spray we used three red lamps and three white lamps connected by a transistor with two parallel circuits, one for white light, one for red light. For those lights the arduino energy was not enough. Thus, we used a 9 V power plug.

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Led

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Problems

Pins already contain electrical charge:

To connect our pipe circuit to the arduino, we wanted to read the digital pin. While we uploaded the signal via serial, we discovered that the pins already contained a electrical charge although the circuit was not yet closed. To circumvent this problem we attached groundings by resistors. These connect the pins with ground. So the right signal was read by serial.

Find a right transistor:

For the light effect of the pepperspray we needed a transistor circuit. The circuit was easy to build but to find the right transistor not. Transistors and voltage regulators look very similar, so our first trials failed because we used no transistor. After we found the “real” transistor we had to decide which transistor type we need. Which number is for which voltage and which type (npn, pnp) is appropriate for our circuit. So for the usage of transistors, you have to read a lot of data sheets and documentations about transistors. As the right transistor was found, we discovered that all transistors differ in their allocation of emitter, collector and base. So we had to read more data sheets and we learned to like them.

Equipotential:

The next problem is also concerned with the light effect of the pepperspray: Our led chain did not react on input from the Arduino pin. The leds were glowing all the time, also without power of the arduino. Different voltages caused this problem. 5 V of the Arduino USB port are not similar to the 5 V of the power supply. This could be corrected by equipotential.  Now the Arduino has only one power source: power plug, which is directly connected to arduino.

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Experiment to construct an amplifier:

The greeting card sound modules were very quite. So we wanted to construct a amplifier. We found a simple circuit diagram and started to construct.

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Because we did not have the named transistor, we used another. Indeed, the bigger speaker was able to make some noise, unfortunately not our recorded barking and siren sound. Because time was precious, we decided to take the physical way. A pipe should amplify the volume. This worked great.

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Sound module:

In spite of correct circuite and correct code we had problems to activate the sound modules with the arduino pins. We checked all contacts with the multimeter and could not find any leak.

Our problem was that we used only one speaker for two music modules. So the 5 V power of the arduino was divided in two parts. The power from source went back over the ground connection from the other sound module without activating the speaker. So each module had only 2.5 V, insufficient power to play back sounds.

The problem could be resolved by usage of a second speaker.

Steel wool in pipe circulation:

The steel wool on the line damaged several times the copper tape and the solder joint. So we lost the contact to the Arduino pin and the whole prototype did not work anymore. We had to exchange the circuit several times.

For presentation we wrapped the steel wool loosely with more copper tape, so that is more softer than the steel wool but as flexible. This is no perfect solution, but we could present our prototype without problems.

Next steps

If we would have had more time to strengthen Rescute, we would like to test more variants for the pipe circuit instead of the steel wool. Perhaps something more smooth with less attrition.

Moreover we would like to use a better sound module with amplifier for the barking and siren sound. So that it sounds more realistic.

If our implementation of our concept is perfect without failures, we would beef up the concept with a fourth rescue level. While the fourth level is triggered, Rescute shall send automatically an emergency call. Maybe this could be implemented by a bluetooth connection to the smartphone, which afterwards dials automatically the 112.

Unfortunately the week is over and we have no time left to extend Rescute.

 

Day 7 – Preparing for the final presentation

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The last day of Sketching with Hardware is known to be the most hectic one, mainly because the projects have to be presented to interested visitors at twelve o’clock. Therefore each group was focused to finalize their project. Some groups were able to refine their program code, others were hectically soldering and drilling. The following “Panic-O-Meter” chart illustrates each group’s mental state over the morning.

 

Panic level on day seven

Panic level on day seven

 

Group 1:
The “Rescute“ team members finished their project already on day six and were quite relaxed on day seven. With their project finished and ready for the presentation they spent the morning capturing good sound samples and preparing their final presentation. After the presentation their panic level raised a bit. But in this case it was not project related, they had to write an important test afterwards.

 

Group 2:
After a hard night of working group two was focused to get their project done. They spent the whole night soldering in the universities computer lab and even slept there. Luckily they were able to finish their electronics and could concentrate on building the last train components. As they haven’t slept a lot group “Osterexpress” started with a very high stress level into the day, but as their project made good progress their panic level decremented significantly over the morning. Minutes before the presentation their project was finished and ready for the public demonstration.

 

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Group 3:
Team “Togebear“ had to fight against some small faults, due to a bad contact inside their bear. They spent quite some time finding the exact problem, but as they found it they were able to solve it pretty quickly. The rest of the morning they focused on code optimization and cleanup. After the teddy bear passed the final functionality tests they were ready and good to go for the presentation.

 

Group 4:
After a hectic Tuesday team “Looping Louie” finally got their game running. The morning before the presentation should be spent for optimization and optic fixes, but it came worse. As the team played some test matches “Louie” had some blackouts and they got worse from minute to minute, until “Louie” completely denied to work. Hectically (panic level ten and higher) the team tried to resolve the problem, but could not allocate it before the presentation. Shortly after the presentation the problem was identified as a soldering error on the motor control board, which led to a complete burnout of the motor control unit.

 

Group 5:
Team “Madlab” detected some servomotor calibration problems in the morning. They were quite stressed as they were not sure if they could solve it until the presentation starts. Luckily they were able to find the correct motor calibration and enjoyed some test games. Servomotor control, LEDs and magnets were working properly, therefore their panic level went from “total freak-out” to “absolutely chilled”

 

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Group 6:
The day started good for team “Ghostcamera” because their project was already working on Tuesday evening. They did some final configuration tasks and tried a lot of different test cases to ensure that the camera setup will be working properly when the public presentation starts. Because they did not run in any major problems denying a good presentation their panic level was dead low the whole morning.

 

At twelve o’ clock most teams were ready, others not, but the public presentation started anyway.

 

The final presentation

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After – for the most teams – working the whole morning to make their projects presentable, the time for public presentation of the projects was finally there. The employees of the media informatics and human-computer interaction groups visited the lab to see the creations of this semesters students. Each group presented their ideas and final prototype to the visitors and finally the winner of this seasons “Sketching with Hardware” was chosen by vote.

 

Group 1

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Group 1 presented their idea in a darker setting then our well-lit lab, because it provided a more realistic scenario. The final prototype of their protective teddy “Rescute” had most of the features that were planned in the brainstorming session. During the presentation all three escalation levels of the teddy worked perfectly: Dog barks at the first level,a  police siren and lights at the second level and a pepper spray (for the safety of the audience it was replaced by deodorant) at the third level. These features should  repel an attacker immediately.

 

Group 2

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After working the whole night and morning the “Osterexpress” group finally had a working prototype in their hands: A completely self-made train, cut with a lasercutter and equipped with several servo motors to cause mayhem during the otherwise placid easter holidays. The train consists of multiple wagons that are loaded with small plastic easter eggs and that are ready to fling them around whenever the train driver decides so. Although the train was a little under-motorized, the audience loved the “tossing-eastereggs”-functionality.

 

Group 3

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“Togebear” was the name of the prototype that group 3 created. Unlike most of the other groups, they managed to finish their project the day before, so there was no overnight stress or morning-panic for them. To strenthen long-distance relationships, the “Togebear” sprays the fragrance of the significant other whenever a email from the beloved one is received and the heart it is holding blinks. It also provides a feedback opportunity by pushing its ear, which will send an email to the beloved one. The audience liked this idea because it was the only non-malicious one in the lineup.

 

Group 4

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Group 4 worked until minutes before their presentation to produce a working prototype of their “Looping Louie”-game but didn’t make it. While they had it working at one point, as it naturally is with a bunch of cables inside a childs toy, it broke. More specifically on the day of presentation the motor that was turning the arm of the game just stopped working. They explained the issues they had in detail and the plans they had with the game as well. They day before they even  played it using a KI that was implemented on the computer and communicated with the Arduino. Maybe we can see a working prototype at the Open Lab Day.

 

Group 5

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The “Madlab” game that group 5 implemented was also on the brink of not working properly at the time of presentation, but fortunately they made it shortly before the presentation. They adapted a marble run to become even harder to play using different techniques like switches that invert the axis. One could control the board either using knobs or using a position sensing device. Some of the features were a bit flaky (i.e. switches not triggering), but all in all it looked like a fun (or hard) game to play.

 

Group 6

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“Ghost Polaroid” is the name of the project that group 6 was tackling. It is supposed to work like a simple polaroid camera by taking a picture and printing it, but instead modifies the images and puts a ghost into the background or replaces the faces on the image by famous internet memes. They hacked a cheap digital camera and printed the image using a thermal printer, all inside a laser-printed case. The image processing was done on the computer. Although the whole process took a while, the audience loved to participate in this mischief and getting their faces replaced by the grumpy cat.

 

The Winner

In the end, every visitor got a vote in the shape of a plastic star and had to give his or her vote to a project. They had some time to talk to the individual groups and possibly try out some of the prototypes by themselves. Then the winner of this seasons “Sketching with Hardware” was chosen:

“Ghost Polaroid”

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While everyone received their participants medal, they received a copy of the current edition of ct Hacks as an additional special. Congratulations.

Day 6 – A final sprint

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Only one day left for the final presentation! Some teams had already completed their main features and  concentrated on improving or adding new functions on them. Some teams were under deadline pressure because they met some new problems about the features of their prototype. Therefore, all groups worked very hard (some even stay up all night!),  preparing for the  show-time on Wednesday. The detail progress of the individual group is presented  in the following.

 

Group 1

Team Rescue had an intensive but enjoyable day. Their LEDs in the eyes shined, the perfume in the belly sprayed. After choosing the right transistor they met a frustration about the contact problem: the loudspeaker didn’t work. After checking of their arduino programs and also with the help of our teacher they solved it finally by using a second loudspeaker!  Then they were somehow relieved and could optimize their teddy bear for the show-time tomorrow.

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Group 2

The “train” team has seen a little frustrated. After completing building shell with the laser cutter, they had problems with the electronic circuit,which was considered at first easy to do: The servos for popup of the Easter eggs didn’t work well. Under deadline pressure they worked all night with only two hours sleep. Thank goodness,  they finally got it! The train fulled with Easter eggs was steering for success.

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Group 3

Team Togebear had an easy day. They had solved the equipotential problem with an appropriate transistor. All they need to do was putting the space spray in Togebear. Now was the cute Togebear totally alive. Maybe they tried adding some new features on them? Let’s see how would the Togebear surprise us tomorrow!

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Group 4

Team Looping Louie seemed to have an relaxed day as well. They have completed all electronics and mechanic buildings after four days hard working with probably the most complicated hardware elements: sensors, motor, position and hit detection, potentiometer… Respect!

In the afternoon they tested it together with Eva and it worked so good. We couldn’t wait to enjoy the game tomorrow!

 

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Group 5

Team Madlab made a good progress. After finishing the main features, they kept on building the additional game board with tilt sensor, which connected to Servomotors. Furthermore they pasted a large amount of  LEDs under Madlab Box, which turned on if the ball was running through it. It was not an easy job: one wire goes wrong, others don’t work.

Cheer up!

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Group 6

Team Ghostcamera had a dramatic day with happy and depression. They had already completed all the technical features and started building the old-style camera box with laser cutter. In the afternoon they attempt to take a test picture, but the problem came. Because of a USB connect error, the picture couldn’t completely show up in the computer, like a true ghost picture! They had checked the USB wires connected to the arduino program but it seemed to be no problem. After a long time search they found the point: in the arduino program they wrote a delay function of only 2 second, which was too short for a USB connect.  After extending it to 5 second, it worked perfectly.

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It was a long day for the final sprint.Were all the groups ready for the end presentation tomorrow? Let’s see!
 

Day 5 – Crucial stage is beginning

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Two days left for final presentation the common problem of all groups is the missing hour for sleeping because of daylight saving time. But there is no problem that could not be solved. Each group is highly concentrated on own problems and solutions. Panic, frustration, joy and success are close to each other.

Basics of electronics have been internalized, now highly sophisticated questions and problems occured. Most of them could be solved by close communication and collaboration between the groups and with our teachers. In the following the progress of the individual groups is summarized.


Group 1:

Team Rescute had a hard day with a lot of frustration but also with success and joy. A long time was required to find a right transistor to connect a parallel circuit of 6 LEDs. Every transistor is named differently and the poles are not always on the same position. After the right transistor was found, the circuit did not react on input from the Arduino pin. After long discussions and many tests it turned out that there was a problem with different voltages. This could be solved by equipotential. Now the arduino gets its power totaly by power supply.

Furthermore they tried to construct an amplifier on their own. This failed because a particular transistor was needed but nowhere available. So now a simple physical solution improves the sound. Also the connection of the sound modules and arduino cause problems but this has to be solved tomorrow on day 6.

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Group 2:

Group 2 is working well, the train is starting to take shape. Their strategy of prototyping is very successful, ideas could be implemented straight forward. So today they prototyped a machine, which helps them to fire off the balls of the train. Therefore they had to hack a servo.

Now this concepts was totally judged as good, the balls are flying very fast and wide. Furthermore they constructed the undercarriage of the train. We are all looking forward to see the train in motion.

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Group 3:

Togebear seems to become alive. Now body, head, legs and arms are crochet completely. His face is smiling at all members of the course. It seems as if to say: “Guys, don’t give up”.

So finally group 2 could solve the problem with the space spray. They bought another space spray machine with a trigger by a button. So they could easily connect the machine to Arduino.

Also as group 1 they suffered because of the equipotential. Here the problem was more difficult to solve because at the power suppy of the arduino the could not found any voltage. “Somtimes it is magic”. But Togebear is still smiling. Cheer up, guys!

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Group 4:

Louping Loui is gaining momentum. The most technicical problems could be solved, so the guys were able to assemble the game with all electronics and mechanic.

Thereby they discovered some further problems.

With a hand gear there was not enough power to lift Loui. So now they use a crank. It is not as fast as a hand gear but the power is adequat. Because of shortage of space they decided to remove the ground on the swivel plate. But at this position a potentiometer is required and potentiometers need ground. But this has to solved on day 6.

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Group 5:

The functionality of Madlap is advancing rapidly. Today they implemented tilt sensors with potentiometers. This was not so easy because sometimes its was too fast, sometimes too slow. So tact was required highly. Furthermore they attached rubber band on servos. Here it was difficult to tighten them. It seems the implementation needs as high attention and tact as playing Madlap. Furthermore they constructed a switch where a light turns on, if the ball is running through it.

The biggest problem of group 5 was the Arduino. It broke down. Why? Nobody knows. After some irrational solutions it worked again. “It is magic”.

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Group 6:

Team Ghostcamera, seem to have some help from supernatural friends. They are making good progress.

The print with background images works. At the beginning they had some problems with the format because of the Java Print API, but those could be solved. The hardware of the camera was complicated to hack. Some cables were pulled out. But they solved it, too. Now they are creating a box for the polaroid camera with Illustrator. Keep it up, girls.

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A successful day is over now. Only one day is left. It looks like all projects can be finalized successfully. Good luck to everybody!

Day 4 – Work in Progress

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Being the first day of pure project development, day 4 had a very special feeling to itself. The groups dedicated themselves to the advancement of their projects, aided by the always needed help of the tutors. The Arduino platform begins to feel natural, its workings are more and more understood, and the first deeper insights are made (who knew that an output set to HIGH still differs to the permanent 5v output?).

Transistors make their first appearance, almost every group makes use of them, as they prove quite useful to close circuits when needed. The poor labeling on the transistors-box makes it more fun, as it is necessary to search for specs online to see if they are n or p switches.

Some groups have first minor or major breakthroughs, solving problems they had in a different way than previously planned.


Group 1

The Rescute team is well on their way. Solved is the problem of the spraying of the pepper spray, the LEDs are also working as planned, thanks to the additional power now used. A bit of frustration about the limited range of arduino servo motors came up, therefore effectively limiting the range of the bear’s neck. Originally it was planned for the bear to turn its head a creepy 180° on each side, now it looks like he will have to be able to turn its head 180° on one side only. Maybe hacking a servo motor will help.

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Group 2

The second group works hard on its project. It proved to be more challenging than previously anticipated, as seemingly simple tasks like the compressing of a spring prove difficult to realize with the resources at hand. Thankfully, being the creative people they are, team 2 members can compensate these problems through ingenious alternatives or workarounds. For the construction of their toy train, they make use of the laser cutter upstairs, and the result is very satisfying. Nonetheless, all of this requires lots of energy and concentration from the team 2 members, leading to part of them to almost fall asleep during the lunch break.

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Group 3

The togebear has seen some progress as well. The knit-work (yes, you read well, this bear is 100% handmade, something a soul-less laser cutter could never achieve) is almost done, meaning that the outside of the bear is almost ready. The inside of the bear proves more challenging than expected: when receiving an email from a loved one, the bear should spray some perfume. Using a hacked airwick system proved to be tricky, as reversing the motor rotation (it needs to go in both directions) proved an impossible task. Building an h-bridge did not solve the issue, maybe some of the used mosfet transistors where not suited for the used voltage. An hacked servo motor (not limited to 180° rotations) was used instead.

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Group 4

The Looping Louie team moved to the laboratory upstairs, as they need the space and tools it offers. Probably one of the most complicated projects hardware-wise, it makes sense for them to be close the equipment. Being physically removed from the rest of the other groups makes it more difficult to judge their progress, but whenever one needed something from upstairs, she or he would hear a small Eureka shout, signaling a further success of group 4, approaching the end goal step by step.

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Group 5

Today post arrived for the Madlab group, it was the game they are going to hack. Finally having the game, they were quickly able to make some progress. Surely it did help, that they didn’t lose time the previous days, thinking ahead of what and how to do it. Servomotors were quickly attached to the game, LEDs were tested, boards altered. Group 5 may have had a delayed start due to the late arrival of the game board, but they managed to make up for the time lost, and then some. If they keep up with this pace, they will be out of work by monday.

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Group 6

The Ghostcamera team had some important hardware arrival as well, now having a functioning printer for their project. The idea is to have a camera take a picture of you and then print it, but with one twist: the printed picture will have some sort of monster on it, be it a ghost or zombie, or whatever. This surely has to be the most complicated project from a software point of view, but the team members are concentrated and seem very confident about the outcome.

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All in all it was a very productive day. Each team was able to make significant progress, each team already faced problems, some of them are already solved. Creative thinking seems to be the key here. The lesson learned today seems to be not to give up immediately, but also not to fixate on one approach. If something does not work after scrupulous researching and trying, then it is time to think of a different solution to the same problem.

Another important aspect of today, was the fact that we really got our hands dirty, and quite quickly. Almost every group used power tools like power drills, dremel or power saws, as well as special machinery like the laser cutter. These are tool that some of us used for the first time. It became quite clear, that this course would not be completed by simply putting some lego together, but that custom work is necessary.

Even the components used in our electrical circuits became more sophisticated. If there was the idea that sketching with hardware could be completed by simply putting some pre-made components on a bread-board, after today the reality became clear: it is much more than that. We finally understood the importance of transistors and switches. It is one thing to read about them in a chapter of some lecture where they are mentioned briefly, but it is a totally different thing to understand how they work in order to use them in our projects. If we want to power some LEDs with an additional power source, how can we control this source? Transistors! If we want to make a motor rotate in 2 different directions, without physically switching cables, how do we do that? Transistors! Thankfully the tutors were there to answer our questions, an we all had some, ranging from where can i find xyz to more technical ones.

This was a very long day, but thankfully the weekend awaits, and monday the show will go on!

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