Alco Bong 9000

This is an alcoholic bong, two ultrasonic elements forces the water into small particles that forms a mist. The elements is normally used for water in decorations or water humidifiers.

I got this old Ikea bowl from a second hand store. It holds the electronics for driving the ultrasonic elements, as well as an MCU to drive some leds.

There’s two systems that is powered from a single 6S LiPo battery.
The ultra sonic elements is apparently sensitive about over voltage and will fry if the voltage exceeds 24V. The first system consists of a buck that caps the fully charge voltage of 25.2V down to 24.0V. That system is activated by a momentary switch on the front.

The second system drives the RGB LED’s. A nice party bong should look good. A small Arduino Nano is driving some WS2812 RGB leds around the glass pitcher. A buck converter caps the voltage at 5V that is used by both the WS2812 RGB strip and the MCU.
The led lights is slowly breathing when the alco bong is idle, and rotates the color hue when in use.

The glass pitcher was glued on the bottom with epoxy and seemed to bound well with the wooden bowl.

Orkide Random – A IoT flower with pretty random power

A video posted by Tim Gremalm (@timgremalm) on

Probably the most random plant in the world, it fetches a “true” random signal and display pretty colors on a WS2812 addressable LED strip.
The seed is based on one of the best randomization generators; cosmic background radiation from Yet another Internet of Things device made out of the ESP8266, the dirt cheap powerful WiFi enabled microcontroller.


IoT Nalle dances to Twitter feed

An Internet of Things enabled teddy bear that dances at filtered Twitter statuses.

To move the teddy bears arms servos is used. It’s a pretty simple setup, some extenders for the arms that is going through the real arms of the teddy bear.
The servos is quite weak, so they bearly move the arms at all.

Mounting of the servos.

The electronic setups contains of a small cheap microprocessor called ESP8266. The ESP8266 have a small WiFI-antenna integrated in the breakout board and can hook up to any access point, or even create one.
I’m running the firmware NodeMCU , it’s a real time LUA interpreter. So the firmware is only programmed once on the flash. To write your own program you just transfer them over serial UART, and the firmware will save the script on flash.
The processor is running at 80MHz so it’s pretty fast.

I’m using Twitters API to fetch the latest post on a specific search term. The API gives me a detailed formated JSON file containing the time and date of the post, as well as the post.
The Twitter API is quite messy to work with, a lot of headers and authentication is required. The ESP would likly handle both the SSL and the big JSON format, but it will steal some CPU-time and it’s hard to work with. I made a PHP-proxy for the twitter feed, parsing the time and date and presenting it in unix timecode. The message of the post is stored as an MD5 hash sum.
On the IoT Nalle i keep track of the already “danced” Twitter posts and only dnaces to new posts.

Final assembly, a lot of hot glue and screws was used.

Interactive LED balancing board

A video posted by Tim Gremalm (@timgremalm) on

An interactive game were the visitors can build complex structure with help from an interactive LED balancer.
The installation was part at Vetenskapsfestivalen.

It’s a project by Stig Anton Nielsen read more about it in this post.

TeiSteadyBuilds from stig anton nielsen on Vimeo.


A video posted by Tim Gremalm (@timgremalm) on


The loadcells is build from 16 layers of conductive carbon packaging film. The recistance ranging from 500k to about 450 Ohm loaded at 8kg. Because it’s a so huge range the loadcells can be directly hooked up in a voltage divider, no amplifiers needed.
3 load cells us used to detect the direction and force of the balance. They are really sensitive to touch, small pressures from fingertips will be easily detected. A backside is that the film tends to be squashed so that it takes long time form the form and resistance to return.
The value from the 3 loadcells is arranged in 3 forces 120 degrees apart. The Forces is calculated into a resultant that is describing a thrust vector.
The thrust vector is indicated with a led strip of addressable WS2812 LED light. The stronger the force, more inbalanced, the greater the red marking will grow.

Att this Google Drive document I’ve collected som measuring data from the loadcells. There’s also some information of how the resultant is calculated.

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] 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.


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.