Monthly Archives: June 2017

An ExoArm For The Elderly

via hardware – Hackaday

Prosthetic and assistive technologies have come have come a long way in recent years. When there are not only major medical research organizations, but individuals getting on board designing tools to improve the lives of others? That’s something special. Enter a homebrew essay into this field: ExoArm.

Attached to the body via what was available — in this case, the support harness for a gas-powered weed-eater — which distributes the load across the upper body and an Arduino for a brain, ExoArm designer [Kristjan Berce] has since faced roadblocks with muscle sensors meant to enable more instinctive control. So — for now — functionality is limited to a simple up and down motion controlled by two switches. It is worth noting that the down switch is currently mounted in such a way that when the user moves their arm down, the ExoArm follows suit, so there is some natural feel to using the arm in its present iteration.

Developed with the elderly — and others who need a boost to physical strength to live a normal life — in mind, this prototype is able to curl up to 10kg in excess of its own weight. Presently, the only motor is on the elbow joint — granting a basic range of motion — with one adapted to the shoulder joint forthcoming! And, costing only $100, it’s a heck of a start.

We’ve featured some impressive individual forays into hackers helping others, humans and animals alike!

Filed under: Arduino Hacks, hardware

Enginursday: X-Band Motion-Triggered Music

via SparkFun Electronics Blog Posts

Some of you might remember the Enginursday: Sound Wave Printing post I did back in January when I mentioned getting more into Doppler Radar sensors. I did some experiments with an HB100 Microwave Motion Sensor, but I also ended up ordering one of Parallax’s X-Band Motion Detectors. Motion Detectors that operate in the X-Band frequency, at 10.525 GHz, are commonly found in security systems and automatic door-operated applications.

My first prototype was pretty neat with the ability to detect movements within a room or yard — or even through walls and windows. Not only that, but it did what I needed it to do in terms of being less susceptible to false triggers in comparison to the passive infrared (PIR) motion sensors I’ve utilized in the past.

I mounted all the components onto a small wooden board with a base to make it easily portable. On the front, you’ll see the ON/OFF SPST Rocker Switch and NeoPixel Ring.

Prototype Front

On the back I installed the Parallax’s X-Band Motion Detectors, SparkFun RedBoard and a small self-adhesive breadboard.

Prototype Back

The blue trimpot you see in the photo above adjusts the sensitivity, offering direct line of sight detection via the antenna on the printed circuit board (PCB) surface, which includes the module’s transmit and receive antennas, from roughly 8 to approximately 30 feet. When enabled, the detector takes short Doppler radar measurements.

X-Band Antenna Orientation and Signaling

Any motion detected from the antenna PCB area causes oscillations at the module’s output pin that I hooked up to the SparkFun RedBoard. It’s really trying to look for that frequency difference between the outgoing and returning signals. If motion is detected, the output signal oscillates from a low to a high state.

To represent the intensity of the motion, I added the visualization from the NeoPixel Ring for 12 color state changes starting from white (with no detected motion) to red (as the highest detected motion).

NeoPixel Lowest State - White

NeoPixel Highest State - Red

All that being said, I do want to take it a step further eventually and implement some sort of audible alarm. For those of you who know me or have read any of my other posts, I’m not ashamed to say this was initially inspired and created as a paranormal investigation device. I actually used it quite successfully to not only validate some unexplained phenomenon, but as a helpful debunker tool.

As it’s been sitting on my desk for a while now, I thought to myself, “Well, what else can I do with it and still keep it relatively portable?” Let’s just forget ghosts for a second. Music maybe? Yeah, sort of like a mini theremin. I mean they are both essentially comprised of the same fundamental building blocks: antenna, oscillator and mixer.

Great thing was I only really needed to add two extra components to make it happen: SparkFun’s MP3 Trigger and an external speaker.

X-Band Plus SparkFun MP3 Trigger

The toughest part of the project was really playing around with the sensitivity of the detector. In the end, I decided to keep it simple and represent an octave of piano notes. It turned out to be a lot of fun, and I’m looking forward to expanding more on what I started here.

Let me know what you think in the comments below!

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An Arduino-based doorbell/messaging system for your lab

via Arduino Blog

If you work in a lab, the last thing you want is someone barging in when you’re about to complete your latest experiment or build, disturbing all of your hard work. You could use a paper note, or perhaps lock the doors, but if you’d like to inform potential disruptors of what you’re doing and give them a way to signal you, this system looks very useful.

The device, which is installed in a psychology lab’s door, uses an Arduino Uno to display an LED for “Experiment In Progress” or “Clear,” and has a backlit LCD screen below for more explanation. The screen’s backlight powers up via a sonar sensor if someone approaches, and messages can be updated over Bluetooth.

Finally, if you’d like to get the person inside’s attention, it even a doorbell feature that blinks a light and optionally beeps. For more info on the project, check out its creator’s Imgur set or Reddit post.

MagPi 59: the Raspberry Pi PC Challenge

via Raspberry Pi

Hey everyone, Lucy here! I’m standing in for Rob this month to introduce The MagPi 59, the latest edition of the official Raspberry Pi magazine.

The MagPi 59

Ever wondered whether a Pi could truly replace your home computer? Looking for inspiration for a Pi-powered project you can make and use in the sunshine? Interested in winning a Raspberry Pi that’s a true collector’s item?

Then we’ve got you covered in Issue 59, out in stores today!

The MagPi 59

Shiny and new

The Raspberry Pi PC challenge

This month’s feature is fascinating! We set the legendary Rob Zwetsloot a challenge: use no other computer but a Raspberry Pi for a week, and let us know how it goes – for science!

Is there anything you can’t do with a $35 computer? To find out, you just have to read the magazine.

12 summer projects

We’re bringing together some of the greatest outdoor projects for the Raspberry Pi in this MagPi issue. From a high-altitude balloon, to aerial photography, to bike computers and motorised skateboards, there’s plenty of bright ideas in The MagPi 59.

12 Summer Projects in The MagPi 59

Maybe your Pi will ripen in the sun?

The best of the rest in The MagPi 59

We’ve got a fantastic collection of community projects this month. Ingmar Stapel shows off Big Rob, his SatNav-guided robot, while Eric Page demonstrates his Dog Treat Dispenser. There are also interesting tutorials on building a GPS tracker, controlling a Raspberry Pi with an Android app and Bluetooth, and building an electronic wind chime with magnetometers.

You can even enter our give-away of 10 ultra-rare ‘Raspberry Pi 3 plus official case’ kits signed by none other than Eben Upton, co-creator of the Raspberry Pi. Win one and be the envy of the entire Raspberry Pi community!

Electronic Wind Chimes - MagPi 59


You can find The MagPi 59 in the UK right now, at WHSmith, Sainsbury’s, Asda, and Tesco. Copies will be arriving in US stores including Barnes & Noble and Micro Center very soon. You can also get a copy online from our store or via our Android or iOS app. And don’t forget: there’s always the free PDF as well.

Get reading, get making, and enjoy the new issue!

Rob isn’t here to add his signature Picard GIF, but we’ve sorted it for him. He loves a good pun, so he does! – Janina & Alex

The post MagPi 59: the Raspberry Pi PC Challenge appeared first on Raspberry Pi.

Process Automation: Relays and triacs

via Dangerous Prototypes


Andy Brown designed and built this relays and triacs controller board that he could use to automate his homebrewing process:

The heaters, fridge and fans that control the temperature in my brew fridge need to be switched on and off and that’s what this board is designed to achieve.

As you can see from the diagram the main features of the board are:

  • Three relays for basic on/off switching. To solve one of the issues with the STC-1000 controller I will use 16A, name brand relays for maximum reliability.
  • A triac. This will give me the ability to do phase-angle ‘dimming’ control and will be used for proportional heater or fan control.
  • USB connectivity to the host PC via a USB-to-UART IC.

More details at  Firmware source code available on github.

Extend Eagle CAD tool with ULPs: Writing your first User language program

via Dangerous Prototypes


Yahya Tawil posted a detailed how-to on writing ULP’s for Eagle CAD:

In this tutorial, you will learn how to write your first ULP in Eagle CAD to add a new capability to your CAD tool.
User Language Program (ULP) is a set of extensions for Eagle CAD users to either facilitate a routine job in an automated way or do a job that can’t be done without a ULP’s help. For example, the only way to import an image to your PCB design is by using the command import-bmp ULP. Auto-placement, exporting BOM, and renumbering parts in a schematic are all routine jobs with which ULP can help.

More details at

Via the contact form.