MAMEFrame – Sweet All In One Portable MAME System

Video game enthusiast [NEIN] loves MAME. The one thing he doesn’t like much about MAME is moving large heavy MAME cabinets around. So what do you do if you want to take your games on the road? [NEIN] decided to come up with a portable MAME solution that includes everything all in one box so there is virtually no set-up time to get playing. He calls it ‘The MAMEFrame‘.

It may appear that this is a standard 2-player DIY controller, however, it is anything but. The display is housed inside the encloure — a video projector that connects to the Raspberry Pi via an HDMI cable. [NEIN] opted to use a Raspberry Pi instead of a large PC to help keep things light and samll. It’s almost like the two were made for each other. The projector has a built in battery and USB port. The Raspberry Pi is powered by the 5 volts supplied from the projector’s USB port making this unit completely portable and wireless. Just plop it down on a table, point it at a wall and you’re ready to guide Pac-Man to level 256!

Did you know one of the very first Raspberry Pi hacks ever was a MAME build?

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Hackaday Prize Entry: An Electric Vehicle From Recycled Parts

In the future, just about everyone will be driving an electric car. We’re seeing the beginnings of this, and that means electrics and hybrids are showing up in junk yards. What does that mean? Tons of big batteries and powerful motors to build an electric vehicle from recycled parts.

A few years ago, someone exceptionally smart did the math on the environmental friendliness of different makes of vehicles from cradle to grave. The most environmentally friendly car to buy wasn’t a Prius, Leaf, or Tesla, but a used car; an old Civic or Rabbit. The logic makes sense – after two or three hundred thousand miles under its timing belt, the Civic or Rabbit has already paid the cost of forging the body and refining the plastic. Obviously, then, the most environmentally friendly car would be reusing the batteries and motor out of a newer hybrid.

For his Hackaday Prize build, [mauswerkz] is taking a 2001 BMW 330ci coupe and replacing the motor and transmission with some salvaged EV equipment. In this case, it’s the transmission and inverter from a Lexus GS450h and the batteries from a Chevy Volt ‘Extended Range’. Where the magical junkyard [mauswerkz] is pulling this equipment out of is anyone’s guess, but he did it. Maybe you can too.

So far, [mauswerkz] has the charger out of the Chevy Volt hooked up to the inverter and transmission from the Lexus and is making stuff turn. It’s only running at 200V instead of the final voltage of 650, but it’s enough for a proof of concept. Now it’s just a matter of stuffing everything inside the BMW.

Of course going to a junk yard isn’t the only way to get an EV. The more enterprising builder might want to build their own EV completely from scratch, starting with a block of foam. Yes, it even looks better than the BMW.

The 2015 Hackaday Prize is sponsored by:

Mimimalist Arduino Gaming Platform

A pretty color LCD screen, an Arduino, a buzzer and a joystick is all you need for a minimalist gaming console for under $20. At least, that’s all [João Vilaça] needed to get this sweet version of Tetris up and running. (He’s working on Breakout right now.)

It’s a testament to the current state of the hardware hacking scene that [João] could put this device together in an afternoon for so cheap, presumably after waiting a while for shipments from China. The 320×240 SPI color TFT LCD screen used to cost twice as much as this whole project did. And wiring it up is a simple matter of connecting this pin to that pin. Almost child’s play.

Equally impressive is the state of open source software. A TFT library from Seeed Studios makes the screen interface a piece of cake. [João] wrote his own sound and joystick code, and of course the Tetris gameplay itself, but it’d be much more than a few weeks’ work without standing on the shoulders of giants. Check out [João]’s Github for the project code and stick with us after the break for a demo video and some of our other favorite Arduino gaming hacks.

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Tiny Robot Jazz

Microcontroller-based projects don’t have to be fancy to be fantastic. Case in point: [r0d0t]’s “Musicomatic: the random jazz machine“. Clever programming and a nice case can transform a few servos and a microcontroller into something delightful.

musicomat_schematicsHardware-wise, there’s really nothing to see here; a speaker and some servos are hooked up to an ATmega328. We think it’s cute to have the microcontroller control its own power supply through a relay, but honestly a MOSFET in place of the relay or better still using the AVR’s shutdown sleep mode would be the way to go.

Nope, where this project shines is the programming. Technically, it might make some of you cringe — full of blocking delays and other coding “taboos”. But none of that matters, because [r0d0t] put his work in where it counts: the music. You simply must hear it for yourself in the clip after the break.

The basis of making music that humans like is rhythm, so [r0d0t] doesn’t leave this entirely to chance. The array “rhythms” has seven beat patterns that get randomly selected. The other thing humans like is predictability and repetition, so choruses and “improvs” repeat as well. All of the random notes are constrained to the pentatonic scale, which keeps it from ever sounding too bad. (The secret sauce of Kenny G.)

In short, [r0d0t] packs a lot of basic music theory into a very basic device, and comes up with something transcendent. We’re a bit reminded of the Yellow Drum Machine robot, and that’s high praise. Both projects are testaments to building something simple and then investing the time and effort into the code to make the project awesome.

For another slice of [r0d0t]’s excellent minimalist pie, check out his take on the classic Snake game: Twisted Snake.

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Measuring The Accuracy Of A Rubidium Standard

A rubidium standard, or rubidium atomic clock, is a high accuracy frequency and time standard, usually accurate to within a few parts in 1011. This is still several orders of magnitude less than some of the more accurate standards – for example the NIST-F1 has an uncertainty of 5×10-16 (It is expected to neither gain nor lose a second in nearly 100 million years) and the more recent NIST-F2 has an uncertainty of 1×10-16 (It is expected to neither gain nor lose a second in nearly 300 million years). But the Rb standard is comparatively inexpensive, compact, and widely used in TV stations, Mobile phone base stations and GPS systems and is considered as a secondary standard.

[Max Carter] recently came into possession of just such a unit – a Lucent RFG-M-RB that was earlier in use at a mobile phone base station for many years. Obviously, he was interested in finding out if it was really as accurate as it was supposed to be, and built a broadcast-frequency based precision frequency comparator which used a stepper motor to characterise drift.

Compare with WWVB Broadcast

WWVB Receiver
WWVB Receiver

The obvious way of checking would be to use another source with a higher accuracy, such as a caesium clock and do a phase comparison. Since that was not possible, he decided to use NIST’s time/frequency service, broadcasting on 60 kHz – WWVB. He did this because almost 30 years ago, he had built a receiver for WWVB which had since been running continuously in a corner of his shop, with only a minor adjustment since it was built.

Comparator Circuit Installed in a Case

His idea was to count and accumulate the phase ‘slips’ generated by comparing the output of the WWVB receiver with the output of the Rb standard using a digital phase comparator. The accuracy of the standard would be calculated as the derivative of N (number of slips) over time. The circuit is a quadrature mixer: it subtracts the frequency of one input from the other and outputs the difference frequency. The phase information is conveyed in the duty cycle of the pulses coming from the two phase comparators. The pulses are integrated and converted to digital logic level by low-pass filter/Schmitt trigger circuits. The quadrature-phased outputs are connected to the stepper motor driver which converts logic level inputs to bi-directional currents in the motor windings. The logic circuit is bread-boarded and along with the motor driver, housed in a computer hard drive enclosure which already had the power supply available.

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Hackaday Prize Worldwide: Shenzhen

That’s right, we’re headed to the epicenter of electronics manufacturing next month: Shenzhen, China. We have a ton planned and this is the quick and dirty overview to get you thinking. If you are in the area (or are itching to travel) join us for a week of hardware hacker culture. Highlights for our tour include:

  • Meet Up on June 18th – (RSVP details coming soon)
  • Zero to Product PCB Workshop on June 19th – RSVP Now
  • Hackaday Talks presented at Maker Faire Shenzhen on June 19th and June 21st
  • Hackaday Booth at MFSZ on June 20-21

Zero to Product Workshop at MakerCamp Shenzhen

shenzhen-makercamp-drawingMakerCamp brings 30 talented Makers, Hackers, Designers, and Engineers together for a few days to build a makerspace inside of a shipping container.

We won’t be part of that build team (registration is open until 6/1 if you want to be). We will be supporting the event as part of the workshops that help celebrate the completion of the space. A mobile hackerspace full of interesting tools is one thing. But the sharing of knowledge, experience, and skill is what truly makes a hackerspace work.

zero-to-product-workshop-LAOur Zero to Product workshop created by [Matt Berggren] has been generating a ton of buzz and will be offered at Shenzhen MakerCamp.

RSVP for the Workshop

The workshop runs from 10am to 6pm on Friday, June 19th on the grounds of Maker Faire: Shenzhen. The event covers PCB design and at the end you will have laid out a development board for use with the ESP8266 WiFi module.

We were totally sold out for the workshop in LA a few weeks ago this is another chance to join in. If Shenzhen is a bit too far for you to travel, we are also planning the next installment in San Francisco on June 13th.

2015-bamf-meetupHackaday Shenzhen Meetup

If you just want to hang out, so do we! On the night of Thursday, June 18th we’ll be rolling into an area bar for a tasty beverage and a night of interesting conversation. As always, we want to see the hardware you’ve been working on. We do recommend bringing things that fit easily in your pocket or backpack since we’re meeting up to spend some time with other Hackaday community members in the area.

We don’t have the location nailed down for this one. Check this post again as we’ll be adding it here. And if you have a bar to suggest to us please leave a comment below.

The picture above is from just a few weeks ago. We had a huge turnout for the BAMF meetup. There was a ton of hardware on hand which makes for really easy conversation as you meet other hackers for the first time.

Talks by [Mike] and [Sophi] plus Booth at Maker Faire Shenzhen

[Mike] is giving a talk on Friday, June 19th about the power of Open Design to move education forward. [Sophi] will be presenting her talk on Sunday, June 21st about making stuff that matters and working on research equipment used to investigate the world around us such as solar, medicine and disease.

Come to the Faire to hear our talks, but make sure you swing by the Hackaday booth as well. We’ll be bringing some of our most favorite projects to exhibit but we can’t resist the opportunity to do something interactive. Stop by and build an oscillator, wire up a sequencer, and create your own rudimentary music based on [Elliot Williams’] series Logic Noise.

Tag Along with Hacker Camp Shenzhen?

hcsz2015-thumbnailOne of the adventures we’ve always wanted to take part in is Hacker Camp Shenzhen which is run by Hackaday alumnus and Hackaday Prize Judge [Ian Lesnet]. The week-long camp leverages [Ian’s] knowledge of the area, manufacturers, markets, and people to provide tours and workshops for those interested in manufacturing. It just so happens that HackerCamp lines up the same week as all of the Hackaday events. We can’t take part in the entire thing, but are hoping that we have a free day to meet up (and possibly tag along) with the HackerCamp crew.

The 2015 Hackaday Prize is sponsored by:

Ask Hackaday: Long Endurance Quadcopter

Quadcopters are useful little flying machines. They can be used in all sorts of applications, from mapping, to inspecting long pipelines, to border surveillance, or simply for fun. They all have one thing in common, however – a relatively short battery life. Because quadcopters use brute force to churn through the air, they require a lot of energy. More energy for longer flights means more batteries. More batteries means more weight to carry, which requires even more energy. If you want longer flight times, something has to change. Or does it?

A small start-up company called Horizon Unmanned Systems based out of Singapore claims their quadcopter can fly for up to four hours on a single charge, or up to two and a half hours carrying a 2.2 pound load. They claim to be able to pull this off with a novel approach. First, they fill the hollow frame of the quadcopter with hydrogen gas. They use that gas to power a cute little miniaturized fuel cell LiPo battery hybrid gizmo. And that’s about it. The rest is just standard quadcopter stuff.

The secret to all of this is the miniaturized fuel cell, and how it works. Unfortunately, this is as close as we’re going to get (pdf) for a datasheet. Fuel cells are nifty devices that take hydrogen and oxygen and convert them into water, along with electricity. While that sounds simple, making one is not. And making a miniature one light enough for a quadcopter is down right hard.

How would you increase the flight time of quadcopters? Fuel cells are a great idea, but is this technology within the reach of the modern hacker? We’ve seen people make them from scraps out of a junkyard, but how would you miniaturize it and make it light enough to be used as a practical power supply for a quadcopter?

Thanks to [Joseph Rautenbach] for the tip!