LED lights in Iceland

LED pixel wall at Keflavik airport

At the airport a stumbled on some cool LED fixtures, it was some kind of addressable LED with an extraordinary diffuser made out of textile.
You can see the beautiful animation of a volcanic eruption lava on the right screen, and a sweet animation of aurora on the left.


Addressable LED facade at Harpa concert hall Reykjavík

They had lit up the whole facade of Reykjavíks concert hall Harpa.
It had small narrow LED strips in each window pane that covered the building completely, it looked beautiful at night.

Chalmers Robotförening – ett hackerspace eller makerspace?


Ett hackerspace är ett ställe som drivs av medlemmar där folk med samma intresse av datorer, verkstad och teknologi kan träffas och samarbeta. [1]
Skillnaden mellan ett hackerspace och makerspace är hårfin, båda termerna står för samma sak, en plats för likasinnade att träffas och arbeta på projekt. På Wikipedia så gör man ingen skillnad på ett Hackerspace, Makerspace eller Hacklab.

Make Magazine har en artikel om just skillnaden mellan makerspace och hackerspace där dom skriver att ett hackerspace har mer fokus på programmering och elektronik, och makerspaces ett bredare fokus och är mer öppet för allmänheten. [2]
Hackerspaces.org skriver att makerspaces ofta satsar på målet av en produkt, medans hackerspaces satsar på intellektuella vägen. [3]

Chalmers Robotförenings klassificering

Chalmers Robotförening har robotik som huvudinriktning, robotik involverar programmering, elektronik och mekanik vilket stämmer bra överens med ett hackerspace.
CRF har inte alltid utgivet sig för att vara ett hackerspace, det var först på senare 2000-tal när termen “hackerspace” började bli mer känd som vi insåg att föreningen stämde in bra under klassificeringen hackerspace.

Vår verkstad är inriktad åt mekanik för robotar, men den är inte begränsad till det. Exempelvis så kan vi om vi vill såga trä i vår verkstad, men det är ingen träverkstad för det. Den kommer nog inte heller bli speciellt anpassad för träarbete då utrustning för trä inte riktigt passar vår förening och det är dyrt att investera i.
Föreningar grenar ut sig och blir bredare med tiden, det är naturligt. CRF har blivit mycket bredare under dom 11 år vi funnits, men CRF är inte tillräckligt brett för att kalla sig för ett makerspace.

Apropå ordet “hack”

Ofta finns en rädsla för ordet “hacker” eller “hack”, dess negativa klang har byggts upp av film och media som för det mesta belyser negativa händelser. När en datorattacker utförts som varit hack så har ordet hacka förknippats med datorattack. [4]
Detta är förstås felaktigt, i själva verket så är det “crack” eller “cracking” som bör användas i det sammanhanget. [5]
Att hacka innebär att man på ett kreativt sätt experimenterar och utforskar för att tänja på begränsningar i ett system. [6] Att hacka ett system kan leda till att säkerhetshål upptäcks som i sin tur kan utnyttjas av “crackers”. Att hacka något är alltså inget ont i sig.

[1] https://en.wikipedia.org/wiki/Hackerspace
[2] http://makezine.com/2013/05/22/the-difference-between-hackerspaces-makerspaces-techshops-and-fablabs/
[3] https://wiki.hackerspaces.org/Makerspace
[4] https://en.wikipedia.org/wiki/Hacker_%28computer_security%29#History
[5] http://www.catb.org/jargon/html/H/hacker.html
[6] https://en.wikipedia.org/wiki/Hacker_culture

Positional LED lights for Electric Longboard

I made some positional lights for my electric longboard to be able to be seen in traffic.

The rear red light have to be able to fold in when the board is placed on its butt.
A hinge was mounted, and a spring is holding the light tube up.

White electric tubing is used to protect a LED-stripe from dirt, it also diffuses the light.

The LED-stripes is powered by a buck converter, switching the voltage down from 25V to 12V.



Battery Chassis for Electronic Longboard

To have the LiPo battery’s exposed underneath the longboard could damage them if something hit them. A strong chassis for the battery’s would protect them, as well as covering the cables from dirt.
The chassis is primary made out of 8mm polycarbonate, with a sheet of 1mm flexible PET cover.
The 8mm thick sides will hopefully take up the forces from any direct bumps.

CAD Drawings

CAD-files (Zipped Solidworks and DXF)

Cam Lock Screw

For locking the chassis to the board I used cam lock screws, the same that is often used in IKEA furniture.
The cam lock seems to come loose due to vibrations, so another solution might be needed.

Electric Longboard with VESC

This longboard is driven by a BLDC-motor, that is controlled by a VESC (Vedder’s Electronic Speed Control). The throttle and brake is controlled by a wireless Wiimote Nunchuck.


The base of the driveline is a kit by DIY Electric Skateboard (http://diyelectricskateboard.com/product/single-motor-electric-longboard-kit/).
The kit is made for the SK3 motor series and included trucks with motor mount, wheels, pulleys and timing belt.
The motor mount is welded into the truck, the design is really good and the welding job is well done. The drive pulley is the weak point in the drive line, it’s wobbly and hard to calibrate. DIY Electric Skateboard seems to have switched it for a new pulley made out of aluminum now.

The motor is a Turnigy Aerodrive SK3 168kv 2400W Brushless Outrunner Motor (http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=38055).


On the board I use 4x3s LiPo 8Ah 30C (http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=32214), it gives about 350 Watt hours of energy.


The motor driver is developed by Benjamin Vedder, he have been developing several years now and he have been implementing a lot of nice features into the ESC.
The VESC can drive a brushless motor sensorless, it measures the back-EMF and can track the position very accurate even at low RPM’s. It also has regenerative braking that charges the battery’s while braking.
A nice feature is also the cruise control, it’s PID regulated and very accurate because of the good tracking of the motors position.

I used a nice IP67 rated rubber sealed case for the VESC (http://www.biltema.se/sv/Bygg/El/Fast-installation/Kopplingsdosa-2000021071/).
A big capacitor us coupled together with the VESC, it creates a big inrush current when the battery is plugged in. A big inrush current can create sparks that oxidizes the connectors and make big ripples in the voltage in to the VESC that can cause damages. Vedder made a small PCB that slowly charges the capacitor, it’s based on a charging schematic from the forum Endless Sphere.
The capacitors and the inrush limiter is hosted in the casing as well.

Wiimote nunchuck

The Nunchuck for Wiimote has a nice grip and several extra buttons to use for extra functions. Nyko does make a wireless version of the Wiimote Nunchuck.
The Nunchuck is communicating with the Wiimote through I2C, so is the wireless receiver for the wireless version of the Nunchuck. The wireless receiver is stripped of its case and hooked in to a I2C bus on the VESC.
Because the Nuncuck is made for gaming it keeps sending the last known command on connection loss, for example so that the gamers gas pedal won’t be affected in game. This is not a good thing when you are driving for real.
Vedder has made a replacement PCB for the Nunchuck chassis that using the NRF24L01+ radio. It’s more safer and have a greater sending distance.

The longboard


Driving experience

Although I have no longboarding or skateboard experience i found it quite easy to ride the electric longboard. I found it easier to keep my balance on the board while having constant power driving it forward. The ability to brake also makes it easier to get on and off.
It’s a really fun way of transportation, it’s fast and you can carry the longboard every where when don’t driving.

CyckelLjudet & Festmaskinen at Regnbågsparaden West pride Göteborg

After assembling CyckelLjudet we managed to arrive at Götaplatsen were the parade Regnbågsparaden were supposed to start.

The solar panels worked really great, we had no trouble at all and the LiPo was charged nicely.

We did use an old Sennheiser wireless transmitter to send the audio from the DJ-booth at Festmaskinen to the PA-speakers at CyckelLjudet.
We had some problems with wireless interference, but it hold up well most of the parade. Go 80’s technology!
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CyckelLjudet – Attaching electronics and solar panels

All pimped out and ready for the west pride parade Regnbågsparaden!

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To be able to drive the amplifier for the speaker we use an UPS. On top of the UPS you can see the solar regulator Solar80.
The solar regulator is charging a 6S 8Ah LiPo battery pack. The solar panels will generate maximum of 600W of power, and the PA-system will draw about 65W of power, so the battery will be more of a buffer.

After some spec-readings we realized that the Solar80 wouldn’t handle the maximum of 70V that the solar panels could generate, it only supported 48V. So we switched it out for Flexmax 80.
Both the controllers were designed for lead-acid battery’s and not for LiPo battery’s. I was missing a parameter to set the charge voltage, also there was software limitations that you couldn’t go around, like the charging current for example, you could only go as low as 5A.
We’re trying out the solar panels and solar regulator in the sun charging the LiPo. The stop-charing-limit was set to 25.2V which is the voltage of a maximum charged LiPo, but the solar regulator was still inputing voltage well above 25.2V because the solar regulator is designed for lead acid battery’s. We then set the maximum-charging-voltage to 24.8V that seemed to help, the voltage over the battery didn’t reached over 25.2V.

Cables from the solar panels.

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Amplifier/mixer in place, and so is the LED-bars.

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