A Robot That Can Still Keep Its Balance After A Night In The Pub

September 27, 2017 by Jenny List 6 Comments

One of the star attractions at the recent bring-a-hack prior to our London unconference was [Dan]’s two-wheeled self-balancing robot. As the assorted masses of the Hackaday readership consumed much fine ale and oohed and ahhed over each others work, there it stood on a pub table, defying all attempts to topple it.

In a way a successful self-balancer can look surprisingly unexciting because it achieves the seemingly unimpressive task of just standing there and not doing much except trundling about, but to take such a superficial view belies the significant feat of engineering that gives the self-balancer its party trick. And it’s no mean achievement to create one from fairly basic hardware, so how has he done it?

The 3D-printed frame holds a pair of stepper motors to do the hard work, while a piece of stripboard acts as carrier for boards containing the MPU6050 accelerometer and DRV8825 stepper motor drivers. Meanwhile the brains of the whole show started as an Espruino Pico but has since been moved to an ESP32.

There is a linked GitHub repository with all the code, and if our description of seeing it in a London pub isn’t good enough for you then you can see it in action in the video below.

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An Unconference Badge That’s Never Gonna Give You Up

September 20, 2017 by Jenny List 10 Comments

When your publication is about to hold a major event on your side of the world, and there will be a bring-a-hack, you abruptly realise that you have to do just that. Bring a hack. With the Hackaday London Unconference in the works this was the problem I faced, and I’d run out of time to put together an amazing PCB with beautiful artwork and software-driven functionality to amuse and delight other attendees. It was time to come up with something that would gain me a few Brownie points while remaining within the time I had at my disposal alongside my Hackaday work.

Since I am a radio enthusiast at heart, I came up with the idea of a badge that the curious would identify as an FM transmitter before tuning a portable radio to the frequency on its display and listening to what it was sending. The joke would be of course that they would end up listening to a chiptune version of [Rick Astley]’s “Never gonna give you up”, so yes, it was going to be a radio Rickroll.

I evaluated a few options, and ended up with a Raspberry Pi Zero as an MP3 player through its PWM lines, feeding through a simple RC low-pass filter into a commercial super-low-power FM transmitter module of the type you can legally use with an iPod or similar to listen on a car radio. To give it a little bit of individuality I gave the module an antenna, a fractal design made from a quarter wavelength of galvanised fence wire with a cut-off pin from a broken British mains plug as a terminal. The whole I enclosed in a surplus 8mm video cassette case with holes Dremmeled for cables, with the FM module using its own little cell and the Pi powered from a mobile phone booster battery clipped to its back. This probably gave me a transmitted field strength above what it should have been, but the power of those modules is so low that I am guessing the sin against the radio spectrum must have been minor.

At the event, a lot of people were intrigued by the badge, and a few of them were even Rickrolled by it. But for me the most interesting aspect lay not in the badge itself but in its components. First I looked at making a PCB with MP3 and radio chips, but decided against it when the budget edged towards £20 ($27). Then I looked at a Raspberry Pi running PiFM as an all-in-one solution with a little display HAT, but yet again ran out of budget. An MP3 module, Arduino clone, and display similarly became too expensive. Displays, surprisingly, are dear. So my cheapest option became a consumer FM module at £2.50 ($3.37) which already had an LCD display, and a little £5 ($6.74) computer running Linux that was far more powerful than the job in hand demanded. These economics would have been markedly different had I been manufacturing a million badges, but made a mockery of the notion that the simplest MCU and MP3 module would also be the cheapest.

Rickrolling never gets old, it seems, but evidently it has. Its heyday in Hackaday projects like this prank IR repeater seems to have been in 2012.

London Calling: The Hackaday UK Unconference Roundup

September 19, 2017 by Jenny List 22 Comments

A trip to London, for provincial Brits, is something of an undertaking from which you invariably emerge tired and slightly grimy following your encounter with the cramped mobile sauna of the Central Line, its meandering international sightseers, and stampede of besuited commuters heading for the City. Often your fatigue after such an expedition will be that following the completion of a Herculean labour, but just sometimes it will instead be the contented tiredness of a fulfilling and busy time well spent.

Such will be the state of the happy band of the Hackaday community who made it to London this weekend for our UK unconference held in association with our sponsor, DesignSpark. A Friday night bring-a-hack social in a comfortable Bloomsbury pub, followed by Saturday in an auditorium next to one of the former Surrey Commercial Docks for a day of back-to-back seven-minute talks laying out the varied and interesting work our readers are involved in.

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The Wrencher On The Road In The UK

September 1, 2017 by Jenny List 4 Comments

Here at Hackaday, we are a team of technical writers who spend our days keeping abreast of the wonderful world of hardware as we write up the interesting things that cross our timelines and serve them up everyone to enjoy. That is however only part of the picture, the other half of the Hackaday family is you, our readers and our community. You are a wonderfully diverse group of people who do some fascinating things, and you are what gives us life.

From time to time, Hackaday makes it out on the road, we have events, we host meetups, and we spend time with you, the community of which we are a part. Of course, our world can be an annoyingly big place at times, so for a lot of us these meetups are too far away. As a Brit, for example, the upcoming Hackaday Superconference in Pasadena, California, is a somewhat unattainable dream without shelling out a significant chunk of the old hard-earned on travel.

In the very short term we must continue to disappoint many of our worldwide readers because we can’t have meetups all over the world and all at once. But we can at least provide succour to our British readers this month, with more than one opportunity to get to know Hackaday writers as we go out on the road.

In the first instance, I’m going to be in Hebden Bridge, Yorkshire this weekend. I’ll be giving a couple of talks, one on Friday at the Wuthering Bytes festival, and the other on Saturday at the Open Source Hardware Camp. I’ll be bringing along the remainder of my stock of Hackaday stickers left over from SHA Camp, and I’d love to see what you’ve been getting up to.

But worry not if you can’t make it to Yorkshire, for there is another chance for Brits to meet us this month. Our London Unconference on the 16th of September may have been a speedy sell-out, but because we have no wish to disappoint those of you who missed out on a ticket we’re also running a bring-a-hack meetup the night before. We’ve hired the Drawing Room at the Marquis Cornwallis, a pub not too far from Russell Square Tube station in London, so come and have a pint with us and show us what you’ve made. Get your skates on, it’s not much more than a couple of weeks away!