open-hardware – Open Source Mechanic blog cat /dev/random | strings | grep "For being ignorant to whom it goes I writ at random, very doubtfully" Tue, 10 May 2016 21:50:54 +0000 en-US hourly 1 Seabot and science hack day Dublin 2015 Mon, 16 Nov 2015 20:52:32 +0000

Brian telling us about SeaBot, tried and tested on UCD lake, confusing local ducks who just wanted food. #SHDD

— Sci Hack Day Dublin (@SciHackDay_Dub) November 15, 2015

Many thanks to all of the organizers and contributors to science hack day Dublin.

It was fascinating to see what a roomful of fun and talented scientists can accomplish over a weekend. The event and collaboration helped me bring seabot from a concept towards reality. Here are some details and goals of seabot:


Seabot is a marine platform for electronic hacking. It was inspired by Cesar Herada’s Protei, James Gosling’s liquid robotics and 600 million year old prior art by Portuguese Man of War polyp colonies.

P. physalis. Photograph by A. E. Migotto, Center of Marine Biology, University of Sao Paulo, Brazil.

P. physalis. Photograph by A. E. Migotto, Center of Marine Biology, University of Sao Paulo, Brazil.

The original plan was to begin with a data gathering buoy and progress to a moving platform. But with access to UCD’s 3d printer, the help of Mohamed and Eoin, we were able to create a sailing platform along with a 3d printed propeller for those rare days when Irish wind falls below 100kph.

We began with a multihull because it gave us a wide, stable platform with the least amount of plastic and hours on the 3D printer. The model we used was a bottle boat created by Richard Albritton on Thingiverse. Because it used ordinary 500ml soft-drink bottles as pontoons, it used even less plastic.

Richard Albritton’s bottle boat.

I had the code to make the ATiny85 blink the light at the ambient temperature. Unfortunately the source code was on an encrypted partition of a crashed laptop but when it is available, I’ll provide a link here. (which is easier, cracking Symantec’s drive encryption or decompiling the bytecode inside the Atiny?)

When we tried floating the temperature-flashing buoy in UCD’s lake,  the swans thought we were trying to feed them. This reminded me that some of the kids in Cesar Herada’s educational project suggested a shark-shaped seabot to scare fish away.

Greg was our navigator. He worked on software for reading a GPS so the Seabot knew where it was. Paul worked on hacking the remote control for an RC toy to run the motor or turn the sailboat’s rudder. We’re already beyond our original goal of a data buoy but perfecting a robotic motorsailer will take some time and sea trials.

I used an Arduino Nano to program a cheap (~1 Euro) Atiny85 processor. The processor has an internal thermister and I dual purposed a red LED as a photodetector and temperature blinker. (1 blink per degree C)

I also intended to PWM modulate red and blue LEDs, red means temperature rising, blue means temperature falling. Imagine Toro Nagashi style floating lanterns where the temperature of the water is reflected in the color of the lantern.

But we didn’t have time to make the navigation system work and the last thing we need is more plastic in our already polluted seas. If we can’t make the seabot boomerang back to us, how can we find the seabot? This is where RF comes in. I had a 433Mhz transmitter which Greg found uses a very simple protocol. Toggling the ATAD line toggles the transmitter.
If the seabot can’t come to us, we must go to the seabot. I had some experience with software designed radio, particularly gqrx and Eoin had contributed code patches to cubicSDR. Paul happened to have his HF yagi antenna with him so we decided that this would be how we would track down the seabot. As a bonus, I connected the RF ATAD pin to the Atiny’s temperature controlled PWM pin.

A little RF direction finding, a 17.3 cm antenna inside a soda pop bottle and a 3d-printed hull. We’re in business.  Thanks to all!

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Aruduino Nano programs Super Mario song onto $1 ATiny85 microprocessor Fri, 31 Jan 2014 15:15:14 +0000 My son and I demonstrate how the Arduino playtunes library can be used in a music program which is uploaded through an Arduino Nano microcontroller development board onto a $1 ATiny85 microcontroller chip. LEDs are flashed at musical frequencies and then a photvoltaic solar sell converts this light into electricity and then polyphonic sound.


Infrared, Arduino and Wed, 15 Jan 2014 00:41:45 +0000 What do a smartphone, TV, Wii, DVR, remote control toy flip car and Zibit remote control robot have in common? Each of these devices use an infraRed communication protocol. While searching for a method to control a Zibit and an infrared toy car whose remote is missing, I came across this website: with some very interesting projects. I haven’t yet deciphered the zibit or toy car protocol but I’ll post here if I make any progress.

Why Don’t We Design a Better Wheelchair? Sun, 08 Dec 2013 02:13:29 +0000 In the 1990 film Awakenings, Robin Williams plays Dr. Sayer, a fictionalized Oliver Sachs, who discovered seemingly miraculous effects of the drug L-DOPA on patients who had been trapped in unresponsive states for more than a decade by Encephalitis lethargica. In the film, the doctor is constantly, loosing, dropping and breaking his eyeglasses.

“Where are my glasses?” Dr. Sayer asks.
“On your head!” his patient exclaims.

In an interview with The Atlantic, Sara Hendren the woman behind the Abler accessibility site, asks Why are Glasses Perceived Differently Than Hearing Aids? or wheelchairs, or prosthetic limbs, screenreaders, braille displays, miracle drugs, Stephen Hawking’s voice…
The phrase, “Assistive technology” usually refers to technology to help disabled people, work, play and live productive lives.  But Sara Hendren finds this usage unnecessarily narrow and limiting. Think of the technology you use every day, the keyboards, iPads, earbuds, smart Phones, cars, bicycles, electric dishwashers… Would you be able to perform your job and live your daily life in the same way without these technologies?

Sara adds, “By returning “assistive technology” to its rightful place as just “technology”—no more, no less—we start to understand that all bodies are getting assistance, all the time. And then design for everyone becomes much more interesting.”

I spent many months developing tests for assistive technology for Linux and Solaris desktop operating systems. In the beginning I might have believed that a passable screenreader, big fonts and alternative keyboards would have been enough. I grew to understand the breadth of needs. All of us tweak and tolerate aspects of our personal “assistive” technologies. Things might have to be tweaked more or less for people with special needs, but there shouldn’t be a cognitive disconnect between technology for us and assistive technology for “them.” I once thought that Apple, though violating certain legalistic definitions of accessible technology, had come up with the perfect one-size-fits all accessibility solution in their iPhones, iPods and iPads. But when I brought an iPad to a friend who is recovering from a brain tumor, I quickly learned that further personalization was necessary. Her short-term memory had not yet recovered, she could no longer read and she finds it extremely difficult to form words. Might an iPad help her communicate her needs, desires and creativity? Recently her weak right hand had strengthened enough that she could almost hold the iPad, but her right thumb pressed on the tablet’s sensitive lower right-hand corner and prevented her shaky but more agile left hand from being able to select things. I was only able to see her for a short time before I returned to Ireland but this brief visit was enough to convince me that some combination of existing and invented technologies would help her communicate and recover.

Another friend was told by her brother, who was also born blind, that learning to use a computer would be like learning to play a musical instrument. His explanation puts it into perspective by reinforcing the idea that it takes time for a anyone to adjust to a complex tool, even when that tool is engineered and customized to fit the person. He understood that screenreaders, braille displays and other so-called “assistive technologies” are tools to be mastered, not impossible challenges. Given time, a person can become a virtuoso at the technology which best fits their own body and mind.

iPad not designed for iFamily Sun, 27 Jan 2013 12:48:48 +0000 Microsoft Windows PCs are now fairly easy to configure with different access levels for different family members with products such as Windows Live and NetNanny.

But laptops and desktop PCs are no longer primary internet access devices for kids. iPhones, iPads and similar devices are becoming much more common for school aged children. Some schools are actually requiring them! But iPads/iPods and other ‘i’ devices can’t have separate accounts for kids. Apple’s marketing model is geared towards individuals each buying their own device, thus the ‘i’ prefix to iCloud, iTunes, iPad, iPod, iPhone…

I later learned that it is possible to make separate accounts on iPads only by “rooting/jailbreaking…” the device. But the US made this illegal yesterday with yet another pro-monopoly DMCA provision. Unless someone cares enough to sign the petition against this pro-monopoly DCMA provision, my fancy new iPhone won’t do what “I” want it too.  Monopoly-locked iPhones are also useless outside of a carrier’s region or if a carrier goes bankrupt. Which is why I decided that it is a good choice going with an Android tablet. It allows ‘I’ to do what ‘I’ want far more than the iPad does. Android’s latest version 4.2 OS does have multiuser capability but some Android devices are so inexpensive it is much more practical to have one device per family member.

Apple tablets, phones and iPods aren’t bad devices, but they’re targetted to a particular market, young, urban, singles and dual income no kid couples. The rest of us, are more focused on ability to share, freedom to customize, ruggedness price and portability between networks than on slick eye candy. At least that’s what iWant.