Author Archives: Steven Dufresne

My DIY BB-8: Problems, Solutions, Lessons Learned

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Imagine trying to make a ball-shaped robot that rolls in any direction but with a head that stays on. When I saw the BB-8 droid doing just that in the first Star Wars: The Force Awakens trailer, it was an interesting engineering challenge that I couldn’t resist. All the details for how I made it would fill a book, so here are the highlights: the problems I ran into, how I solved them and what I learned.

The Design Criteria: Portable and Inexpensive

I had two design criteria in mind. The first was to keep it low-cost. Some spend $1000 …read more

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Daylight Saving Time – Whys And Why Nots

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We recently went through our twice yearly period of communal venting called adjusting for daylight saving time (DST), or British Summer Time (BST) as it’s called in the UK. But why are we changing the time? Seriously, who caused all this? Does it do any good? Do we still need it? And what can we do about it? As it turns out, most of us want it, as you’ll see below.

We Live In Good Times

It might help you to know that we have it easy, or at least programmers do. In ancient Roman times, rather than subtract or …read more

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Cheap Dual Mirror Laser Projector

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[Stanley] wanted to make a laser projector but all he could find online were one’s using expensive galvanometer scanners. So instead he came up with his own solution that is to be admired for its simplicity and its adaptation of what he could find.

At its heart is an Arduino Uno and an Adafruit Motor Shield v2. The green laser is turned on and off by the Arduino through a transistor. But the part that makes this really a fun machine to watch at work are the two stepper motors and two mirrors that reflect the laser in the X …read more

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Custom Data Writer Board For 1996 Plane’s GPS

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[Dmitry Grinberg] recently bought a Cessna 150 that contained an old IFR-certified GPS from 1996, the KLN89B. The GPS unit contains a database which by law has to be kept up-to-date for IFR flight. The problem was that, while Honeywell still supplied the data in electronic form, [Dmitry] had no way to update the GPS. The original ways for doing it are either no longer supported, too expensive and a pain to do, or not available to him due to the way his GPS was installed.

Two of those ways involved removing a data card which can legally be slid …read more

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Red Dwarf’s Talkie Toaster Tests Tolerance

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In the Red Dwarf TV series, Talkie Toaster wants to know if you want toast, and if not toast, then maybe a muffin or waffle, and it will pester you incessantly until you smash it with a 14lb lump hammer and throw it in a waste disposal. Now [slider2732] has actually gone and made one of the infernal machines!

He’s hidden a PIR sensor in the toaster handle to tell an Arduino Pro Mini when someone is unfortunate enough to be passing by. The Arduino then reads sound files from an SD card reader and plays them through a 3 …read more

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Raspberry Pi Robot That Reads Your Emotions

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It’s getting easier and easier to add machine intelligence to your hacks, even to the point where you sometimes don’t have to install any special software. In this case [Dexter Industries] has added the ability to read human emotions to their EmpathyBot robot by making use of Google Cloud Vision.

Press a button on the robot and it moves forward until it’s a certain distance from an object. It then takes a picture and sends it off to Google Cloud Vision along with a request to do face detection. The response that Google returns is in JSON format and, if …read more

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Power Wheels Rescued, Restored and Enhanced

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It seems Power Wheels are like LEGO — they’re handed down from generation to generation.  [Nicolas] received his brand-new Peg-Perego Montana Power Wheels in 1997 as a Christmas present. After sitting in a barn for a decade, and even being involved in a flood, it was time to give it to his godchildren, though not without some restoration and added features. His webpages have a very good write-up, just shy of including schematics, but you’ll find an abbreviated version below.

Due to time and the flood, not only did it need a new paint job, and some plastic bits restored, …read more

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Ask Hackaday: How Do You Convert Negative Voltages to Positive?

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I have a good background working with high voltage, which for me means over 10,000 volts, but I have many gaps when it comes to the lower voltage realm in which RC control boards and H-bridges live. When working on my first real robot, a BB-8 droid, I stumbled when designing a board to convert varying polarities from an RC receiver board into positive voltages only for an Arduino.

Today’s question is, how do you convert a negative voltage into a positive one?

In the end I came up with something that works, but I’m sure there’s a more elegant …read more

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Alexa Brings Back Singing Fish, This Time It’s A Good Thing

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Remember Big Mouth Billy Bass? That’s the singing fish with which you could torture family members by having it endlessly perform a rendition of either “Take Me to the River” or “Don’t Worry Be Happy”.

Now [Brian Kane], a teacher at the Rhode Island School of Design, has connected Amazon’s Alexa to the fish. Speak the “wake word”, “Alexa”, and the fish’s head turns to face you. Then ask it any question you’d normally ask Alexa and Alexa’s voice answers while the fish opens and closes its mouth in time to the words. Want to know the weather? Ask the …read more

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Crossing Wheatstone Bridges

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The Wheatstone bridge is a way of measuring resistance with great accuracy and despite having been invented over 150 years ago, it still finds plenty of use today. Even searching for it on Hackaday brings up its use in a number of hacks. It’s a fundamental experimental device, and you should know about it.

How It Works

Here’s an easy way to understand how the Wheatstone bridge works. In the schematic are two voltage dividers (pairs of resistors in series): R1 with R2 and R3 with R4. If you do the math, you’ll notice that the voltages across R1 and …read more

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