Category Archives: Raspberry Pi

New tiny parts

In the never ending quest to find a Voltage level shifter, to drive addressable LEDs, I found myself looking at these http://www.ti.com/lit/ds/symlink/sn74lvc2t45.pdf . These ICs can do 3.3V to 5V translation for 2 pins at a whooping 420Mbit and they cost $80c (USD) . So I ordered 5 from TI….

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Yep… that’s damn small. Not sure how I’m going to use those… I have no Surface Mount skills or equipment..Should have read the damn data sheet properly. Anyway, I’m glad there are 5, I will try my damn best to solder those pins to some larger pins and if i break any ill have a few extra to play with. If they work, ill be able to eliminate the Driver Pixel that i use in most of my application, most importantly ill be able to properly test higher data rates for the APA102 and the SK9822 pixel.

Next on the list are these $4 single cell Power Banks:

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These use a single 18650 to produce 5V at a maximum of 1A… With one more nice feature. They don’t have a power button. They activate simply when a load is detected. I’m using this as a test bed, and in a very non recommended way, I’m sure. I have the Output ports of all 4 into 1 Female USB port and was successfully able to power one of my latest creations:

 

White Night 2016 – The Wow Suit

White Night 2016 in Melbourne may not have been as huge as in previous years, but I sure had a blast. I walked around the Melbourne CBD and surrounds for about 7 hours and got my photo taken by A LOT of people! Everyone I ran into seemed to enjoy themselves and really liked the Wow Suit. Here are a few pics from the evening

I had a friend shoot some really good video of the suit, but until I get my hands on it, here is some from my Instagram:

Notice how the Official White Night Instagram account tells me to apply for an art grant next year, even though they sent me a Generic “NO THANKYOU” when I applied for this years event.

One more:

The Wow Suit @whitenightmelb !! #whitenightmelb2016 #whitenight #whitenightmelbourne #whitenightmelb

A video posted by Elec Dash Tron Dot Org (@wow_elec_tron) on

Something new, something BIG!

Work has begun on a marvelous LED Installation for the Maitreya Festival. The project, titled “Space Theatre” will comprise of a huge “planet vs black hole ” diorama !

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Some goodies for the installation above! We are using over 2000 APA102 Pixels, driven by a Raspberry Pi A+. This installation will be built on the backbones of the same tech used int the Wow Suit.

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Here they are fully built and tested! Now onto building the LED layout map…

Wow Suit Gen 3 – Up and Running

Problems listen in the previous entry have been resolved. It seems that I can not push the APA102 strips to run above 5MHz using the Raspberry Pi’s SPI port. That seems to be the maximum before I get noise on the line. 6MHz works as well but you can see some noise on the very end of the block when allot of power is consumed. I think it is a combination of things. but im happy with 5MHZ

 

 

The other issue was the Power Up drain. For now the best forward is to put hardware switches onto each power tap. There are 11 power taps. Ill assign 7 switches on a small perf board that joins all the taps together to the 6 USB power cables. If i start up the sequence sequentially, the LEDs have 0 noise and power on in the OFF state, which is what we want! If i power up all the taps at once, i get a huge whopping bunch of noise and the batteries cut out to protect themselves from overload.

New Panel Layout for the V3 Wow Suit

Here are 2 video demo of the new panel layout:

This one runs a simple pixel pusher to test each pixels colour and location:

This one runs part of the Wow Suits full software rendering suite:

Each panel consists of 255 APA102 LED Pixels. There will be a total of 12 of these panels, however the panels on the arms and body may be smaller.

Wow Suit V 3 – Production Update

I have used up the last of my APA102 strips from my previous order to make the 1st prototype panel for the 3rd Iteration of the Wow Suit.

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This is the panel for the bottom right leg. With this prototype i have 17 strips x 15 Pixels Per Strip totaling at 255 LEDs for one panel. The previous iteration of the Wow Suit had 10 x 16 pixel strips, which were 160 Pixels per block).

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I’m trying to get them as tightly packed as possible. The base block is a piece of felt secured to a thin piece of plastic sheet. Its both rigid and flexible enough to adhere to the cat suit Ill be putting this on to.

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I have also added a pixel inside the RPI casing as the driver Pixel. This pixel is directly connected to the SPI bus on the RPI and is driven by the RPI’s 3.3v Power Supply. Its the best way to get a reliable signal at very high SPI speeds. I’m essentially using the pixel as a voltage level converter. When driving LEDs, the software ignores pixel 0 and sends a blank pixel to it each render.

The Wow Suit V3 – Building has begun

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Above is the brains of the Wow Suit. The Raspberry Pi A+. I have 2, one is a backup in case I step on the 1st :)  For $50 you cant really pass up on this power house. The RPI runs the following stack of software:

I have also placed an order for a body suit, and will be building the 1st panel in the coming days to test out a new layout . Also in the pipeline is 20 Meters of APA102 144ppm LED Strips.

Burning Seed 2015

I didn’t think this through

I learnt some very insightful things last weekend, whilst attending Burning Seed 2015. This was my very 1st “burn” ever!

Above is an awesome still shot of me wearing the Wow Suit and the V4 LED Mask Hot glue is not the best thing to use when making complicated electronics used in the Australian outback! Who would have thought ? Whilst none of my creations suffered at all, it was the very 1st thought that ran through my head as i opened my car at 5pm after a 30 sunny day. I met some very interesting people, one awesome gent told me about E6000 which is a solvent glue that solidifies hard permanently. I will be trilling this for my future wearable projects

The best way to test your power usage is to run it in a real world scenario. The wow suit lasts for exactly 6 hours on 4 x 10ah packs. The 5th power pack, which i use to power the RPiA+, was 70% full after the 2nd night of use. I managed to to swap over the 4 LED power packs at about midnight with the help of my bestest friends.

People LOVE to hug at festivals. Why didn’t i think about this one? about every 3rd person who came up to to check out the suit wanted to hug me. “I want a light hug” …. “bright hug me”….”oh my god woooow…can I please hug you”. This is totally awesome, and an absolutely acceptable way to go WOW in my books! No one was denied a hug…well almost no one, there was that one really smelly naked hippy! The suit stood up to the challenge and didn’t break.

Dancing with Jord in the #wowsuit at #burningseed #burningmanaustralia #burningseed2015 #apa102 #raspberrypi A video posted by Elec Dash Tron Dot Org (@wow_elec_tron) on

Test your code over and over! Whilst standing in front of a small crowd of people, suddenly my whole right side went dark….i immediately freaked out…and then 5 seconds later immediately got a wave of relief when I realised I coded the frame to buffer incorrectly whilst shifting pixels! I then stopped looking down at myself in fear of seeing this dreaded bug every 10 minutes.

If you plan to wear almost 2000 very bright animated LEDs on your body, PLAN your evening accordingly. I found myself unable to enter any small covered areas in fear of freaking out the crowd around me. I also stood helpless as hundreds of very munted people drooled over the animations! This i didn’t mind so much, i just wasn’t prepared for it.

Power Modules for Burning Seed have arrived

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15 x 10Ah @ 5V Battery Modules

All the Battery modules have arrived and all work! Yei!!! I have planned to run the Wow Suit for 3 nights. The suit requires 4 x Modules for the LEDs and 1 module for the Controller. I have recently migrated all my code and control software to a Raspberry Pi Model A+. Im sing the “mraa” NodeJS module to drive the suit via SPI. The A+ only requires 5V!!! Another YEI!

Building MRAA from source on a Raspberry Pi A+

I am using Raspbian (Kernel 4.1) http://downloads.raspberrypi.org/raspbian_latest

You will also need “python” and “git” however these are pre-installed on the device.

Update apt-get

sudo apt-get update
sudo apt-get upgrade

Install NodeJS on a Raspberry Pi A+

latest version of Node for RPI is not supported, gra barchived:
   wget http://node-arm.herokuapp.com/node_archive_armhf.deb
Install it using dpkg
   sudo dpkg -i node_archive_armhf.deb
Test Node and NPM
   node -v
   npm -v
Update npm
   npm update npm
Change npms registry path from https to http
   npm config set registry http://registry.npmjs.org/

Install PCRE

ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/pcre-8.37.tar.bz2
tar jxf pcre-8.37.tar.bz2
chmod 777 configure
./configure
make
sudo make install
sudo ln -sfv ../../lib/$(readlink /usr/lib/libpcre.so) /usr/lib/libpcre.so
sudo ldconfig

Install SWIG 3.07 or higher

http://downloads.sourceforge.net/swig/swig-3.0.7.tar.gz
tar -xzf swig-3.0.7.tar.gz
./configure
make
sudo make install

Install python-dev

sudo apt-get install python-dev

Install cmake

sudo apt-get install cmake

install mraa

git clone https://github.com/intel-iot-devkit/mraa.git
cd mraa

Comment out the following from /src/spi/spi.c
(line 144)
// if (ioctl(dev->devfd, SPI_IOC_RD_MAX_SPEED_HZ, &speed) != -1) {
// if (speed < hz) {
// dev->clock = speed;
// syslog(LOG_WARNING, "spi: Selected speed reduced to max allowed speed");
// }

mkdir build
cd build
cmake .. -DBUILDSWIGNODE=ON -DBUILDSWIGPYTHON=OFF
make

This is where it got weird and i tried something random and it worked

Go into your project directory and install mraa via npm

cd ~projectdirectory
npm install mraa

You then need to copy mraa.node from

~/mraa/build/src/javascript

To

~/projectdirectory/node_modules/mraa/build/Release