Prop: Sign “Rund” for the larp Do Androids Dream?

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For the larp Do Androids Dream we needed a lot of small props to give a Blade Runner feeling of the scene.
Small lit up signs would give that Hong Kong look that is so common in Blade Runner. Carl Nordblom, the set designer, had some ideas about how the sign should look, and had found some sample pictures.

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From the sample pictures I got an idea of how to produce a design. And from that idea I started to make a CAD-design.
The finished design ended up being almost exactly like the CAD-design.
Here is the Drawing of the Round Sign (Do Androids Dream).pdf

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Small wooden block for holding a aluminium plate in a slot.

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The wooden blocks attached on to a sheet of flexible PET plastic.
The sheet is bent around the round aluminum plate with the help of the slots.

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The PET ring is transparent with a blue tint which would not be fitting in a light fixture. So we painted the PET ring in black to make it opaque.

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Warm white 5050 LED strip was glued on to the aluminium plate.
9×6 strips with 54 LED’s on each side makes 108 LED’s in total
108 * 20mA = 2.16A
2.16A * 12V = 26W

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The LED strips is driven by 12V that comes in from JST-connector.
But the sign is supposed to look like an old florescent light, so to give that look the light should look like it flicker occasionally.
I hooked up an N-channel MOSFET IRLML6344 and connected it to a Arduino Nano for timing the random flickering.

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A big steel angle attached to the heavy aluminium plate of the sign, this is used for screwing the signs to a wall. Also the JST power connector, hidden in black heat shrink tubing.

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In the outer sides of the sign round white acrylic plates will be inserted. They will rest against the wooden blocks and hold back by small sprints.
Each side of the sign is mirrored, so one sign have two faces.
The light is powerful enough to project through the white acrylic plastic. And with opaque paint on top will make a huge contrast perfect for a sign.

Prop: Dragon in Noodle Bar for the larp Do Androids Dream?

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For the larp Do Androids Dream we needed a lot of small props to give a Blade Runner feeling of the scene.
An iconic part of the movie is the dragon sign above the Noodle Bar. I thought i could be made out of el wire and it could, it even looked like neon. The light emitting from the el wire was really low doh, I would prefer to have stronger light.

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I started out by placing steel wire in the dragons shape by hand.

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Attaching el wire around the steel wire frame was quite easy, just a matter of placing some transparent tape around it.

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When trying out the outer shape I know I was on the right track, it looked great!

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The dragons tongue is animated in the movie, it’s animated in segments. I was after the same look, so I created two segments for the tongue and had the idea the enabling each segment by turning on and off the high voltage el wire transformers.
I connected a couple of N-channel MOSFET IRLML6344 and connected it to a Arduino Nano.

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µMute – A microwave oven silencer


I’m tired of the buzzer in the microwave oven that is beeping constant up to a minute.
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So I opened it up like any normal hacker would, found the buzzer and snapped it off.

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Sure, the buzzer was irritating, but so would be not to hear when my food is cooked. So i quickly had a look at the PCB and find a very interesting pinout.

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So I soldered on some pins and started to measure the voltage level.
VCC of 5V looked promising for a microcontroller.

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I had a look at the buzzer signal, it was a 2kHz signal with an amplitude of 5VDC.

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I had a rough idea in mind about having a small tune play instead of the 2kHz tone, and it should only play once.
So I shuffled some code together to code to play a small tune from the flash of an Arduino Nano. The flash could only hold about 18k of samples and was played at 8kHz.
https://github.com/TimGremalm/MicroMute
(inspired by http://playground.arduino.cc/Code/PCMAudio)
In lack of a better choice i choose Windows XP’s startup sound.
I shuffled some more code around to sample the original buzzer signal from a GPIO. If the sound is playing at more than 2kHz for a certain time I would trigger the sound.
I applied some time based software filters to filter out some noice.
I build a small amplifier out of an MOSFET (IRLML6344) and a small 0.5W speaker element I found at my local hackerspace.

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I throw it all into the chassis of the microwave oven. There was plenty of space, but i took some precautions to electrically isolate the PCB and speaker.

Unfortunately the sound from the small 0.5W element was too low. It barely was distinguishable against the sound of the microwave ovens fan.

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So I upgraded the element for a 3W element that I found in an old PC speaker, and took some precautions and upgraded my amplifier as well for the more stable Class-D amplifier PAM8403.

MicroMuteSchematic.sch
Schematic PDF

The sound was much louder and you can clearly hear the “Done”-sound from the microwave oven.

Flashbar for festival using sACN over WiFi with ESP8266

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This flashbar, aka blinder, was used under a concert to give a blinding effect for the audience.

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A mosfet driver is enabling the LED’s. The LED’s is 10W element, and there is 8 elements on the flashbar giving 80W of power.
It’s powered from an PC power supply.

The ESP8226 is running a small UDP server and listens for sACN packets. sACN is like DMX512, but over UDP instead of RS-485.
You can find the firmware here https://github.com/TimGremalm/FlashBar.

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The LED’s are screwed down on top of a steel bar to transfer the heat.

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Festivalljus – LED, Lens, Heatsink Assembly

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One of the hardest things with this project is to solve the problem with the heating. 9 pieces of 3W LED tends to get very hot, 27W that have to be transferred to the air.

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If I bend the pins on the led I can make the LED’s go through the PCB. An alternative is to use a lot of small via’s under the LED to transfer the heat to the underside. But I think a direct contact with the heatsink will be more effective.

Assembly PCB with LEDs 3D Without Lens
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Assembly PCB with LEDs 3D With Heatsink Fan
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A CPU cooler should be sufficient enough to transfer the heat out to the air. I don’t know if the fan is necessary.

The whole assembly will look something like this:
Assembly Spotlight With Chassi 3D 2Assembly Spotlight With Chassi 3D 3Assembly Spotlight With Chassi 3D 4

Optics Specification

Alco Bong 9000

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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.

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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.

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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.

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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 random.org. Yet another Internet of Things device made out of the ESP8266, the dirt cheap powerful WiFi enabled microcontroller.
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