A Quadcopter Controlled By A Pi Zero

February 16, 2016 by Brian Benchoff 57 Comments

Flight controllers for quadcopters and other drones are incredible pieces of engineering. Not only do these boards keep an aircraft level, they do so while keeping the drone in one place, or reading a GPS sensor and flying it from waypoint to waypoint. The latest of these flight controllers is built on everyone’s favorite $5 computer, the Raspberry Pi Zero.

The PXFmini controller and autopilot shield is the latest project from Erle Robotics that puts eight servo outputs on the Pi, barometer and IMU sensors, a power supply, and all the adapters to turn the Raspberry Pi Zero into a capable flight controller. Since the Pi Zero will have some computational horsepower left over after keeping a quadcopter level, there’s a possibility of some very cool peripherals. Erle Robotics has been working with depth cameras and Lidar on more than a few drones. This makes for some interesting applications we can only imagine now.

The schematics for the PXFmini are open source in the best traditions of the RC and drone community and will be available soon. You can check out a video of the FXPmini flying around an office below.

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Ridiculously Automated Dorm Room

February 13, 2016 by Al Williams 22 Comments

Take three NRF24L0+ radios, two Arduino Nanos, and a Raspberry Pi. Add a bored student and a dorm room at Rice University. What you get is the RRAD: Rice Ridiculously Automated Dorm. [Jordan Poles] built a modular system inspired by BRAD (the Berkeley Ridiculously Automated Dorm).

RRAD has three types of nodes:

Actuation nodes – Allows external actuators like relays or solenoids
Sensory nodes – Reports data from sensors (light, temperature, motion)
Hub nodes – Hosts control panel, records data, provides external data interfaces

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Hacklet 95 – More Pi Zero Contest Entries

February 13, 2016 by Adam Fabio 8 Comments

We’re well into the second week of the Hackaday and Adafruit ultimate team-up: The Raspberry Pi Zero Contest. The entries have been flying in! As of Thursday evening, we have 70 projects vying for one of 10 Raspberry Pi Zeros, and one of three $100 gift certificates to The Hackaday Store. This week on The Hacklet, we’re going to take a look at a few more contest entries.

We start with [Sean Hodgins] and Blueberry Zero – Keep your Pi in your Pocket. [Sean] can’t leave home without his Raspberry Pi Zero. Carrying all the cables, adapters, and accessories required to power up a tiny Linux computer can be a chore though. He’s created a solution to simplify all that with Blueberry Zero. This custom PCB hat contains an HC-05 style Bluetooth module connected to the Pi’s console port. Serial alone doesn’t make for a standalone Pi, so [Sean] added a LiPo battery and charger chip. A switching power supply boosts the 4.2 V LiPo output up to the 5 V required for the Pi. Now when [Sean] just has to hack out some python code, all he needs to do is open a Bluetooth connection from a cell phone, tablet, or computer.

[Doihaveto] is using his Pi Zero to manage a desktop PC. PC Power allows him to not only turn his computer on or off, but to disconnect the mains power completely. [Doihaveto’s] PC does have Wake On Lan, but he’s run into problems when the system has failed. His Pi provides an extra layer of protection in case things don’t wake up as expected. The board contains two optoisolated connections to a host PC. One is the power switch output, the other is the power LED input. If all else fails, PC Power also can control a solid state relay to completely isolate the computer from mains power. PC Power uses a web interface created with Python using the flask web framework.

Next up is [tomwsmf] with PiFold. Like [Sean] up above, [tomwsmf] can’t leave home without his Pi Zero. Rather than hacking code though, [tomwsmf] is serving up media. PiFold is a wallet containing a Pi Zero powered server. The Anyfesto software package runs on the Pi, serving up songs and files via WiFi. Audio is also transmitted on 88.1 MHz FM via PiFM. A 2500 mAh battery pack coupled with a boost converter keeps PiFold humming away. When the battery needs a charge, [tomwsmf] can use a small solar panel to top up the battery while staying green.

Finally, we have [Fredrik J] with Retrofit Robot. The 1980’s were a golden age of toy robots from Japan. Tomy, Nikko, and a few other companies created devices like Omnibot, which were ahead of their time. [Fredrick] still has his vintage Nikko RC-ROBOT, but it has long since ceased to function. The Pi Zero presents a perfect opportunity to give the little guy a new lease on life. [Fredrik’s] goal is to keep the RC-ROBOT’s original look while giving him new functions. The old DC motors are being replaced with closed loop servos. The servos will be controlled by an Adafruit 16 channel servo driver board. The next step for Retrofit Robot is a big 6000 mAh battery. We can’t wait to see how this one turns out!

If you want to see more entrants to Hackaday and Adafruit’s Pi Zero contest, check out the submissions list! If you don’t see your project on that list, you don’t have to contact me, just submit it to the Pi Zero Contest! That’s it for this week’s Hacklet. As always, see you next week. Same hack time, same hack channel, bringing you the best of Hackaday.io!

Swarm Of Robot Boats Coming To An Ocean Near You Soon

February 12, 2016 by Richard Baguley 31 Comments

Planning a hostile takeover of your local swimming pool? This might help: [Dr Anders Lyhne Christensen] sent us a note about his work at the BioMachines Lab of the Institute of Telecommunications in Portugal. They have been building a swarm of robot boats to experiment with autonomous swarms, with some excellent results.

In an autonomous swarm, each robot makes its own decisions and talks to its neighbors, and the combined behavior of the swarm produces an overall behavior, like ants in a nest. They’ve created swarms that can autonomously navigate, patrol an area or monitor the temperature in an area and return to base to report the results. In an excellent video, [Anders] outlines how they used computational evolution to create these behaviors, randomly mutating a neural net to find the best approach, which is then sent to the real boats.

Perhaps coolest of all: the whole project is open source, with the brains of each boat running on a Raspberry Pi, and a CNC milled foam hull with 3D printed component mounts. Each boat costs about 300 Euro (about $340), but you could reduce the cost a bit by salvaging components and once the less-expensive Pi Zero becomes obtainable. This project will no doubt be useful for many an evil genius who is sick of being splashed by the toughs at the local pool: a swarm of killer robots surrounding them would be an excellent way to keep them at bay.

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Robo Car Via 3G

February 7, 2016 by Al Williams 20 Comments

[Emil Kalstø] has a pretty solid remote control car. We don’t mean a little car with a handheld remote you can drive around the neighborhood. [Emil’s] car has a camera and a cell phone so that it can go anywhere there’s 3G or 4G networking available.

The video (see below) shows the results (along with [Emil’s] little brother acting as a safety officer). The video offers tantalizing detail you might find useful if you want to reproduce a similar vehicle. However, it stops short of providing complete details.

The two batteries onboard will power the vehicle for over 20 hours of continuous use. The 30W motor is reduced with a chain drive to go about “walking speed.” There’s a Raspberry Pi with a Huawei 3G USB dongle onboard and [Emil] uses an XBox controller to do the steering from the warmth of his living room. Of course, a Pi can’t handle a big motor like that directly, so a Phidgets USB motor controller does the hard work. The software is written using Node.js.

The camera mount can swivel 230 degrees on a servo so that the operator can scan the road ahead. The video mentions that steering the car required a heavy-duty servo with metal gears (an earlier attempt with nylon gears didn’t work out).

Overall, it looks like a solid build. We hope [Emil] will share code and more details soon. If you can’t wait (and your insurance is paid up), you might have a go at an even bigger car. Surprisingly, there’s more than one example of that.

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New Angle On Raspberry Pi Zero Hub

February 6, 2016 by Rud Merriam 48 Comments

Collectively, the Hackaday readers sigh, “Not another Pi Zero hub!!!”. But [Sean Hodgins’] hub is different. It has a new angle, literally. Besides, it’s an entry in the Hackaday and Adafruit Pi Zero Contest .

[Sean Hodgins’] acute approach is orthogonal to most of the other hubs we’ve seen. He’s mating the hub at right angles to the Zero. The hub plugs into both the on-the-go USB port and the USB power port. No extra cables or wiring needed. [Sean] plans to release the design on GitHub after his Kickstarter campaign ends. He’s supplying bare boards for those who like the smell of solder paste.

This project nicely triangulates the issues of adding a hub to the Zero. The physical connection is solid with the boards connecting via the USB connectors. Power is supplied through the hub the way the Pi expects, which means all the protections the Pi Foundation built into the onboard conditioning are left in place. This also reduces surge problems that might occur when back powering through a hub and hot swapping USB devices. Another neat feature is the notched corner leaving the HDMI port accessible. Similarly, the Pi’s GPIO pins are free of encumbrance. One drawback is the hub is fused at 2 amps, just like the Pi. It would be nice to have a little more headroom for power hungry USB devices. Maybe another 0.5 amp to allow for the Zero’s usage.

[Sean] snaps the two together after the break.

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Code Craft: Cross Compiling For The Raspberry Pi

February 3, 2016 by Rud Merriam 48 Comments

Sometimes there’s just no place like your desktop. You’ve already got your favorite development tools and references setup or installed and it’s a pain when you’re trying to work on an unfamiliar, or simply uncustomized, system. On your desktop everything is at your fingertips. If you want to search the web, the browser is just an alt-tab away. If you need a calculator, it’s right there to run. Your editor highlights syntax in your favorite colors already.

When developing on a Raspberry Pi, you leave all these creature comforts behind unless you spend the time to configure the Pi to your liking. Then it all gets wiped when you install a new distribution, like the recent change from Wheezy to Jessie. Even then it’s frustrating to switch back and forth between the desktop and the Pi because there is always something on the other system that you need. My usual comment is, “dirty word”, literally.

Cross-developing on your desktop is a very workable solution. We’re going to walk through setting up your desktop and a Pi to do this. This means loading a Pi ARM toolchain on your desktop and a debugging server on the Pi. This’ll let you develop and debug from in the comfort of your desktop. An added advantage is when you put that Pi in a robot you can debug over a wireless link.

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