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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 Michael 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 with a fixed cogwheel and a bearing suspended platform holds all the electronics while it is turning around its own axis. A motor with cogwheel pull the platform around 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

The game is more of a structure for a series of riddles, quizzes or games, to take out and about in bars for a fun night out.

4-12 persons can participate. If more than 6 pers, pairs can be formed. The number of pairs+1 is the number of venues to visit throughout the night.

Each person or pair creates a riddle for the others to solve. The answer to the riddle must lead to a bar, restaurant or other venue, where the next riddle can be presented.

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 along.

An ‘assistant’ – not taking coming along the trip – lays out the order of venues through the trip. This serves the purpose in order for the group to move around town in a short rational path.

For this assistant to know the venues selected, every person or pair inform this assistant (and only the assistant)

Once the route is laid out, the assistant makes a deck of envelopes for the group to bring on the trip. The envelopes are numbered 1..n. Each envelope contain only the name(s) of the next person or pair to present their riddle or quiz.

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.