Raspberry Pi

1918 Articles

Here Comes Santa Claws

December 24, 2015 by 4 Comments

Liberty Games in the UK was looking for a fun way to support charity for the holidays, and we think they succeeded. They decided to set up an arcade crane machine to run over the internet, with each type of toy snagged earning  a donation. Snag a bear, and they will donate £5 to St Mungos, a UK charity that works with homeless or at risk people. Snag one of the rarer Santa toys, and they will donate £20. It’s a great cause, and a nice hack. Behind the scenes, the Internet side of things runs on a Raspberry Pi connected to a PiRack and a couple of PiFace digital interface cards that are wired into the electronics of the crane machine so they could control the buttons on the machine from a Web interface. Unfortunately, it didn’t seem to be running when we tried it, but hopefully someone will give the machine a swift kick shortly to get it going until the Hackaday traffic invariably brings it down again.

One of the interesting thing that they discovered while working on these hacks: they have a pay-out ratio that is determined by the strength of the grabbing arm. The owner can tweak this so that the arm does not grab very firmly, which means a dropped bear. Want to torture your friends with hopes of snagging the best stuffed animals?. Follow the example of this claw machine build all from parts on hand.

Firing Up A Raspberry Pi Zero

December 23, 2015 by 38 Comments

I ordered a Raspberry Pi Zero from Adafruit in their Startup Pack right after they were released. There are a few Greater Than Zero Pis (GTZPi) already on my workbench so my purchase was driven by curiosity, not necessity. With no rush on delivery it eventually got here, and I finally got around to looking at it. My experience with the Pi family began with the Pi B+ and, shortly after that, the Pi 2. The speed difference between them was noticeable so I decided to dive in and further test the performance of the Zero.

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Raspberry Pi Laser Beam Profiler

December 21, 2015 by 3 Comments

[Anthony] at UCLA needed to verify the shape of a laser beam. Commercial units for this, as you would expect, are expensive. But a Raspberry Pi with a Pi Noir camera easily handles the task. Not only is the use of the Pi cool but so is the task – they are using lasers to cool molecules to study quantum effects. The Pi camera without the IR filter captures a wide bandwidth making it suitable for use with non-visible lasers. [Anthony] captures the beam along two axes and plots both curves on the LCD touchscreen. That data, based on the pictures, is also available on a host PC. All this in a super compact package with a 7″ touch screen display.

2D crystal of Yb ions.

One reason I find this fascinating is I did something similar 1977 at the University of Rochester Laboratory for Laser Energetics. My project was measuring the energy cross-section of a laser beam. The research goal of the Laboratory was the study of inertial confinement laser fusion. While [Anthony] uses an entire camera my project was limited to a 1 dimensional array of charge coupled devices (CCD). The output went to a Tektronix storage terminal and was printed on thermal paper for reference. He uses Python running on the target system. My work used a Z80 development system the size of a tower PC to write my program in assembly language which was then executed on a single board computer. We’ve come a long way. My code is long gone but you can get [Anthony’s] on GitHub.

Yet Another Pi Zero USB Hub

December 19, 2015 by 36 Comments

It’s quite fascinating to see the world of hackers rise up and start messing around with new hardware as soon as it’s released. As everyone knows, the Raspberry Pi Zero only has two micro USB ports… a bit lacking for any computer — even one the size of a credit card. While there will probably be an official USB hub coming out someday, we’ve already seen a few home-made versions — though we think this might be the nicest layout so far!

[Richard Hawthorn] threw this PCB design together to give the Pi Zero four USB 2.0 ports. It can be attached by either a USB connector, or by soldering 4 pins between the two boards. It can either be powered off of the Pi Zero, or with an external power connector jack. In a future design he hopes to add pogo pins so it can just be attached and detached whenever you need it.

It’s a bit more involved than simply strapping a mini USB hub to the back of your Pi, but if you’re interested in a more sleek solution, [Richard’s] got all the details on his GitHub.

Open Sesame Raspberry Pi Style

December 17, 2015 by 5 Comments

[Don] installed an Android tablet into his wife’s vehicle and realized he wanted to allow it to operate and monitor the garage door. His biggest challenge? Meeting the (what he refers to) as the WAF or Wife Acceptance Factor. He decided to use a Web app on a Raspberry Pi, along with a handful of switches and a relay. His list of goals were straightforward:

  • Provide the status of the door (open/closed/unknown)
  • Open and close the door
  • Work across multiple platforms
  • Secure enough to connect to the Internet
  • Reliable and simple

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Maker Barn Organizer Creates Makerspace Access Control System

December 13, 2015 by 15 Comments

The MakerBarn is a new makerspace between The Woodlands and Tomball, TX (north of Houston). [George Carlson], one of the founders and a retired design engineer, wanted to make sure only members certified on a machine could use it. He worked with [Kolja Windeler] to create the MACS or Makerspace Access Control System. He has one video explaining MACS and, after the break, another explaining the browser based user interface for the system.

20151205_181615A control box, [George] calls them stations, controls the power to a machine. Member badges have an RFID tag that is read when inserted into the station’s reader. If the member is authorized to use the machine, the power is enabled. For safety, the member’s badge must remain in the reader to maintain power. The reader uses a Photon board from Particle with a WiFi link to a Raspberry Pi server.

[Kolja] developed a Pi system to maintain a database of member numbers and the machines they can use. The list is sent to the stations periodically or when updates occur. The user interface is browser based on the MakerBarn’s LAN so it can be maintained by a computer or smartphone in the space. Presently 21 MACS modules have been built with some going to Hanover University in Germany for their auto hobby shop.

Not only did [George] lead the effort on creating MACS but has been key to getting the construction done inside a pole barn to make the MakerBarn a reality.

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Raspberry Pi Communication Via LASER

December 12, 2015 by 28 Comments

[Nick Touran] wanted to make two Raspberry Pi’s communicate wirelessly. There are lots of options, but [Nick] used a LASER and a photoresistor, along with Morse code. If you don’t find Morse code fancy enough, you could always refer to it as OOK (on/off keying). The circuit uses a common LASER module and an ordinary photoresistor that varies in resistance based on light. A resistor forms a voltage divider with the photoresistor and an external A/D reads the resulting voltage.

The circuit works, but we couldn’t help but notice a few items. Not all photoresistors are as sensitive to the same light wavelengths, so for the maximum range you’d want to pick a particular photoresistor.  While the analog to digital converter is certainly workable, we couldn’t help but wonder if you couldn’t set up the divider to use the inherent threshold of the Raspberry Pi’s input pins for a simpler circuit. Of course, if you used the same technique with an Arduino, you could use the built-in A/D converter, and the A/D converter is probably easier to get working.

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