Delicious Dash Pi Driving Data

November 1, 2014 by Kristina Panos 14 Comments

A few weeks ago, [sentdex] described how Python has changed his life. In particular, it has allowed him to mine Bitcoin automatically, teach other people programming, and realize a full in-car computer for less than $100 using a Raspberry Pi.

It’s based on a model B, which he’s enclosed in a beefy Pi camera case that sits on the dash of his Honda S2000. The screen is a $17 internet special with composite in, which keeps the BOM way down. A 3A switch wired into the ignition ensures that power to the Pi is not rudely interrupted.

A script takes the Pi directly into desktop mode when [sentdex] starts the car. His main goals for the project were setting up a dash cam and communicating with the OBD computer. The Pi pulls various data points including the throttle position, and the user moves through the list with the arrow keys of one of those roll-up keyboards.

In the future, he’d like to upgrade it to live graph the throttle position and add a sensor to show the brake position. Be sure to check out the walk-through/demonstration video after the break.

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Raspberry Pi Brings New Life To Some Old Dinosaurs

October 31, 2014 by Sarah Petkus 7 Comments

Reprogramming the behaviors of a person-sized animatronic dinosaur would have to be among the coolest opportunities to be presented with… This is exactly what [Dr. Lucy Rogers] and a group of fellow techies were tasked to accomplish for the Blackgang Chine park located on the Isle of Wight in the UK.

Before the group arrived, the native dinos didn’t do much else than run a preprogrammed routine when triggered by someone’s presence… which needless to say, lacks the appropriate prehistoric dynamism. Seeing that their dated wag, wiggle, and roar response could use a fresh breath of flair, the park’s technical projects coordinator [Mark Butler] began adapting one of the dinosaur’s control boxes to work with a Raspberry Pi. This is when [Lucy] and her group were called upon for a two-day long excursion of play and development. With help and guidance from Raspberry Pi expert, [Neil Ford], the group learned how to use a ‘drag and build’ programing environment called node-RED in order to choreograph new movement sequences for two of the smaller dinosaurs provided for use. The visual nature of node-RED helped those of the Blackgang staff with little programming experience understand the code at work, which aided in their training. Now they can reprogram the dinosaurs with new actions on the fly if needed.

The Pi in the end turned out to be a cost-effective solution which will give the robot dinosaurs a longer, more fulfilling lifespan to roar and frolic on their island home. Check out this video by [Debbie Davies] to see more…

Thanks Ed, for spotting this one!

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Simple LED Project To Spice Up Your Halloween Party

October 26, 2014 by Rick Osgood 3 Comments

[Paul’s] project is a great example of how you can take a simple project and turn it into something more interesting. He built himself a jack-o-lantern with an Internet controlled RGB LED embedded inside.

[Paul] first wired up an RGB LED to a Raspberry Pi. He was sure to wire up each color using a 100ohm resistor to prevent the LED from burning out. The web interface was written in Python. The interface is pretty simple. It consists of three text fields. The user enters a value between 0 and 255 for each of the three LED colors. The program then lights up the LED accordingly.

[Paul] realized he would need a diffuser for the LED in order to really see the blended colors properly. Instead of using a common solution like a ping-pong ball, he opted to get festive and use a plastic jack-o-lantern. [Paul] removed the original incandescent bulb from the lantern and mounted the LED inside instead. The inside of the pumpkin is painted white, so it easily diffuses the light. The result is a jack-o-lantern that glows different colors as defined by his party guests. Be sure to check out the demonstration video below.

What’s Next On The Raspberry Pi Front

October 22, 2014 by Kristina Panos 30 Comments

Raspberry Pi founder [Eben Upton] recently sat in an uncomfortable chair in London to discuss all things Pi. Having sold about four million units over the last 2.5 years, he feels the future is bright for his original vision of inspiring and helping kids to learn programming.

[Eben] is quite pleased with the Pi-Top, a B+ based laptop kit that’s pulling in backers left and right while completely unaffiliated with the Pi foundation. The kit includes a 13.3″ HD LCD screen, keyboard, trackpad, and an injection molded case, though you can print your own with the included STL files. Kits start at $249 without a Pi and $285 with a B+ included. Robot and home automation HATs are also available separately or bundled with the Pi-Top kit.

The most exciting news is that the $600,000 spent on DSI connectors for those four million Raspis is about to pay off. [Eben] hopes that an official touchscreen will be available for purchase before the end of 2014 or in early 2015. He showed off a 7″ capacitive touch panel that will attach to a display board stacked on a Pi, effectively turning it into a tablet.

[Eben] said that they will not be making a Model C and instead are working on revision A+. He hopes to make an official announcement in the near future.

Finally, [Eben] discussed the importance of community, which played a large part in the birth and evolution of the Pi. He also spoke of Pi Academy, a sort of professional workshop for teachers in the UK who’ve recently been tasked with teaching computer science as demanded by changes in the mandatory UK school curriculum. He hopes that these 2-day seminars will help educators achieve the high expectations recently laid out for students to achieve by age ten.

Reverse Engineering A Bathroom Scale For Automated Weight Tracking

October 18, 2014 by Rick Osgood 16 Comments

[Darell] recently purchased a fancy new bathroom scale. Unlike an average bathroom scale, this one came with a wireless digital display. The user stands on the scale and the base unit transmits the weight measurement to the display using infrared signals. The idea is that you can place the display in front of your face instead of having to look down at your feet. [Darell] realized that his experience with infrared communication would likely enable him to hack this bathroom scale to automatically track his weight to a spreadsheet stored online.

[Darell] started by hooking up a 38khz infrared receiver unit to a logic analyzer. Then he recorded the one-way communication from the scale to the display. His experience told him that the scale was likely using pulse distance coding to encode the data. The scale would start each bit with a 500ms pulse. Then it would follow-up with either another 500ms pulse, or a 1000ms pulse. Each combination represented either a 1 or a 0. The problem was, [Darell] didn’t know which was which. He also wasn’t sure in which order the bits were being transmitted. He modified a software plugin for his logic analyzer to display 1’s and 0’s on top of the waveform. He then made several configurable options so he could try the various representations of the data.

Next it was time to generate some known data. He put increasing amounts of weight on the scale and recorded the resulting data along with the actual reading on the display. Then he tried various combinations of display settings until he got what appeared to be hexadecimal numbers increasing in size. Then by comparing values, he was able to determine what each of the five bytes represented. He was even able to reconstruct the checksum function used to generate the checksum byte.

Finally, [Darell] used a Raspberry Pi to hook the scale up to the cloud. He wrote a Python script to monitor an infrared receiver for the appropriate data. The script also verifies the checksum to ensure the data is not corrupted. [Darell] added a small LED light to indicate when the reading has been saved to the Google Docs spreadsheet, so he can be sure his weight is being recorded properly.

120 Node Rasperry Pi Cluster For Website Testing

October 7, 2014 by Adam Fabio 36 Comments

[alexandros] works for resin.io, a website which plans to allow users to update firmware on embedded devices with a simple git push command. The first target devices will be Raspberry Pis running node.js applications. How does one perform alpha testing while standing up such a service? Apparently by building a monster tower of 120 Raspberry Pi computers with Adafruit 2.8″ PiTFT displays. We’ve seen some big Raspberry Pi clusters before, but this one may take the cake.

The tower is made up of 5 hinged sections of plywood. Each section contains 24 Pis, two Ethernet switches and two USB hubs. The 5 sections can be run on separate networks, or as a single 120 node monster cluster. When the sections are closed in, they form a pentagon-shaped tower that reminds us of the classic Cray-1 supercomputer.

Rasberry Pi machines are low power, at least when compared to a desktop PC. A standard Raspi consumes less than 2 watts, though we’re sure the Adafruit screen adds to the consumption. Even with the screens, a single 750 watt ATX supply powers the entire system.

[alexandros] and the resin.io team still have a lot of testing to do, but they’re looking for ideas on what to do with their cluster once they’re done pushing firmware to it. Interested? Check out their Reddit thread!

Supercapacitors For The Raspberry Pi

October 4, 2014 by Bryan Cockfield 45 Comments

As versatile as the Raspberry Pi is, it has a weakness when it needs to be able to shut down properly during a power outage, especially when handling data-sensitive or industrial applications. To solve this problem, [Pavol Sedlacek] has created a supercapacitor-based UPS specifically for the Raspberry Pi that gives it enough time to properly halt its processes and shut down if it detects a power failure.

The device is called the Juice4Halt. It uses a DC-DC converter to provide power to the Pi from the normal power supply and to charge the supercapacitors during normal operation. It is bidirectional, so in the event of a power failure it works in reverse to take power from the capacitors and feed it back to the Pi. A second DC-DC converter handles power from an external power supply.

A side effect of using supercapacitors as a UPS is that they can also help the Pi survive brownouts. The project site has an incredible amount of detail about the functionality of the device, including circuit diagrams and the source code. We’ve seen other supercapacitor-based UPS units before but this particular one is much more robust and would be truly at home in any industrial or other sensitive setting.