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Ice Dome on a Canal In Denmark


The project started in 2015 from an idea by Alexander Osika, at Chalmers University of Technology. The project was suggested for Smartgeometry 2016 at Chalmers.

A first prototype was set up by Alexander and Mikael in the freeze storage house in Gamla Staden, Göteborg 

Now a few years later (late Feb 2018) I saw cold weather coming on the forecast and started building a few days before it hit Denmark.

This (2018) version is made from a modified tripod to which a large fixed cogwheel is mounted. A bearing suspended platform holds all the electronics such that it is able of turning around its own vertical axis indefinitely. A motor with cogwheel pull the platform around by the larger fixed cogwheel and a motor with peristaltic pump propel the water, a battery powers the motors, heaters and sensors and a servo actuates the tilting nozzle. All settings and sensor data are transmitted wireless via Bluetooth. Electronics in total: Two stepper motors and stepper drivers, Bluetooth module HC-05, Arduino Nano, 5V voltage regulator, 2x TIP120 transistors, Servomotor 180′, 2xThermistors and kanthal thread as heating elements.

The peristaltic pump draws up water through a tube going down through a center hole in the ice cap. The water is then pushed through a tube to the end of the nozzle where it is sprayed on the ice. As the layers of ice are added, a wall of ice will build up, firstly in a circle, then as the nozzle tilts up the three dimensional shape will become spherical.

The speed of the peristaltic pump as well as speed of rotation, temperature settings and servo tilt is adjustable. In this first build the servo was not actively adjusted, just set to a height over Bluetooth like other variables like heat setpoints, flow and rotation. Two PID control algorithms run on the arduino to control the temperature for both the intake tube and in the long nozzle. To distribute temperature, and reduce power consumption the nozzle is constructed from a few layers: The water runs through a PVC tube of about IØ 5mm, on the outside of this is a thermistor placed. The tube and thermistor are drawn through the inside of a cobber tube of IØ8mm which is coated outside with polymide film (kapton tape). This film acts as electrical insulation between the kanthal thread being the heating element which is wrapped around the cobber tube. On the outside of the cobber tube and heater is another layer of polymide film and finally 8mm insulation layer of foam padding with reflecting aluminium tape on top to reflect infrared.

A final power consumption of 300mAh at 8v without heaters on, and 2100mAh with both heaters at maximum. The battery is a 2cell LiPo with 6000mAh capacity. The rig should be able to run for up to 10hours per charge.

Several attempts to print a dome failed due to various reasons. (1) Ice forming in the vertical central tube until rotation of intake PVC tube was jammed from rotating. This was solved by adding the second heating element and additional insulation between ice cap and aluminium tube, this meant a larger hole in the ice had to be drilled. (2) Leakage in peristaltic pump caused large ice formation in gears and bearings – solved by gluing PVC tubing firmly. (3) Ice forming in nozzle causing all tubes to freeze due to low setpoint temperature. -soon the system must run out of points of failure 🙂

(LEFT) To avoid dripping and back flow leading to overicing the first nozzle had its inner diameter reduced using shrink tubing, however, as it was outside thermal protection of the cobber, it soon froze up. (RIGHT) improved nozzle of metal. The PVC tube is squeezed by the cobber tube from the outside to hold this find stainless steel tube in place.

The wall was only a few cm after approx 2 hours of on-off printing (and failing to print further for various reasons)

The project is under development, and more testing is coming up -when the weather allows…

Astronauts could live inside ice domes on Mars

Autonomous Rover

Semi-autonomous rover navigated successfully between preprogrammed coordinates (geolocations).

Throttle is still manual during testing for safety. The Rover hardware was built on an old remote controlled toy car. Controllers, servos, motors and motor controller is buffed up with modern high current electronics all controlled by the PixFalcon with a GPS/Compass sensor. The flight controller is programmed through QgroundControl v3.

The Riddled Barcrawl

A quiz-style night around town where nobody  knows where the group is going. At every new venue, an envelope is opened, a riddle is presented, and the next venue is found. At that next venue, when everyone is ready, the next envelope is opened, and so on.

Riddles can be made by single persons, pairs or groups previously formed amongst the participants. (max 6 groups for the trip not to be too long). Each group must do two things:

A: Choose a venue they would like to visit. This could be a bar, cafe, museum or other. The name and address is sent to ‘The Travelling Salesman’ -AND IS KEPT A SECRET TO OTHER PARTICIPANTS.

B: Design a riddle that somehow lead to the chosen venue. Bring props/questions etc for the riddle along for the event to present to the other participants. The moment to present is dictated by the envelopes.

-For inspiration, see examples of previous riddles below. The solution to the quiz/riddle must lead to a venue, but both name or location (address or GPS) or other ways can be used for leading to the venue.

In this way a series of riddles, each solved at a separate venue lead the group around town. While the entire route remains a surprise to everyone, except the Travelling Salesman (not participating on the night).


The Travelling Salesman: (these instructions are irrelevant if you are not chosen as TTS)

To avoid traversing the city forth and back between bars, a short and rational route is laid out by someone, who is unable to attend the on day itself. This person we call ‘The Travelling Salesman’ and has two crucial roles.

A: Lay out a good route, that both prioritise venue style, opening hours and location of venues. This venue-route is compiled in envelopes that ONLY consist of a number (1-n) on the outside, and names of riddle-makers in the letter inside the envelope. The names or locations of venues is NOT revealed in these envelopes (because the answer to the riddle leads to the venue).

B: (optional) Design a small (or super elaborate) riddle that is slowly revealed through clues in each envelope. This riddle can lead to an additional bar on the route, or just have a solution for other purposes….?

Howerver TTS must first and foremost keep the chosen bars a secret from participants, and make the deck of envelopes for the participants to bring on the day. 

Riddles and quizzes for inspiration (free from my memory)

-A simple 60(or was it 1000) piece puzzle was put on the table.. after having assembled the puzzle, someone noticed messages on the back of the pieces… -Puzzle was turned over (somehow) and the messages turned out to be GPS-coordinates, leading to the next venue..

-A number of fact/name based questions were distributed to participants. Each question could however have more than one answer.. The common answer however was the name of the bar..

-A two litre icecream and four spoons are on the table….Participants start eating from each corner until they stumble upon an item in the icecream – It was excavated, and as it turned out to be a plastic-toy rhinoceros, the bar was guessed to be Rhino-bar, nearby.

-A number of cards were handed out to participants. They contained a flag, and simple statement referring to a historic event. However the flags were not flags from nations, but naval flags, each referring to a letter of the alphabet… Participants laid the cards in a row from oldest to newest historic event and decoded the flags to letters and read the name of the next bar.

-A magazine with adult toys were brought to the table, along with a question-quiz. The participants – slightly embarrassed – found the answers to the quiz by looking through the magazine, and the answers combined gave the name of the next venue.

-A quotation on a piece of paper was presented to the participants. After some confusion the quote was searched online, leading to an article mentioning a newly opened bar nearby.

Happy riddlemaking: everything is allowed.. don’t try not to make it too difficult – nor too easy.

The sign for MAKE:lab

To test the accuracy of the plasma cutter mounted on the KR150 industrial robot arm, we did the sign for MAKE:lab

Although its rough on the edges, it proved a nice easy and efficient way to cnc-cut large sheets of metal.


The Lego Game

Take your box of Lego and sort a number of exact similar piles. The number of piles should match the number of players. I recommend storing the pieces in separate bags for later use.

Now each player has  a handful of pieces, say there are 16 in each pile for example.

1: Now the first player makes a little arrangement of 4 selected pieces from his own pile. While doing so he hides his pieces behind a standing open book or in his lap under the table.

2: When all players are ready, he shows the arrangement in the middle of the table.

3: At the moment the arrangement is shown the other players can copy the arrangement as fast as possible. But!

4: At any moment any of the players copying can say stop, and everyone has to stop building.

5: The copies are now compared to the original and minus points are given for misplaced pieces.

6: Points are noted, and the next player makes an arrangement now with 8 pieces. (repeat from 1)

Finally: The points are summarized such that the weight of points are relative to the number of pieces.

Notes: It can be troublesome to calculate points, so give and take a bit or just rate the figures quickly looking for similarity, then throw points by the paper-sissor-stone method: showing a number of fingers at them simultaneously (one figure at the time – fairplay)

-The fun part here is to just build arbitrary lego figures and train the 3D perception.

Bike -> E-Bike conversion – mechanical transmission

A onedayproject to convert my bike to e-bike.

Well the one day was making the transmission and it was running 50km/h in the afternoon (in a private area) -the more careful design of battery packs and safety systems came later.

It is powered by around 40-50V running a BLDC motor of 290Kv and rated max 1800W. The transmission is gear ratio of around 1/11 (as I recall) -but still the motor runs too slow at low speed driving.

It very lightweight and cheap to build but you need a BLDC controller and I recommend the VESC designed by Benjamin Vedder.

I also recommend having brakes that are stronger than the motorsetup, so the fail happens to the mechanics – not the driver..

For additional details just ask or check out my Thingiverse post

Electric Boat Motor

My diesel motor broke down, so I designed and installed  an electric motor drive.

Great about this project is the way I used different prototyping techniques to fab the timing pullys, and the alu frame.

And even more great is that compared to the diesel engine which had 4 separate liquid systems and electric system – this has just one electric system, and it doesn’t pollute or require any maintenance.

It charges on solar panels 20V boosted up to 60V for the 4x12v batteries (series) that provide the electric power. -I have even been sailing on sun alone 😉

V.1 10kW BLDC 150KV 45-52V 86Ah direct drive – not working 🙂

V.2 10kW BLDCmotor 150KV 45-52V 86Ah timing belt over cast pullys. Worked ok but at low rpm for the motor, causing high current draw.

V.2 25kW BLDC motor 50KV 45-52V 86Ah same timing belt setup, this works perfect from 150 w just driving the boat in harbour without current or strong wind up to approx 2000W in canals etc.

If you are interested in more details, just ask.

I will try to get some shots from the current installation.. to show the pulley setup.