#modmypi

Raspberry Pi re-seller ModMyPi acquired by The Pi Hut

Interesting news in the Pi world today. Official re-seller ModMyPi has been acquired by fellow re-seller The Pi Hut. What this means in the long term is anyone’s guess, but in the official announcement on the ModMyPi website, they have stated that the entire ModMyPi product range will shortly be available at The Pi Hutand that products manufactured by ModMyPi will continue to be manufactured at…

Get a head-start on New Year’s Eve with ModMyPi’s fireworks tutorial for the Raspberry Pi and SenseHAT

Claire Pollard, who recently started work for Pi retailer ModMyPi has started to write some tutorials for their website. On 5th November, she published a great tutorial that uses the Raspberry Pi, together with the SenseHAT, to create a fireworks display. Now, obviously this was for the UK’s ‘Guy Fawkes Night’ celebrations, but it seemed a good idea to point it out to everyone now so that you…

So for anyone interested, these are the things that I ordered as a start believing it is all I need.

Raspberry Pi 2 Model B SBC 1GB Ram  Case - Black Raspberry Pi Modell B+ and RPI2- Multicomp  RPI Power Supply 2A - 5V Kingston 8GB microSD-kort Class10 WiFi USB dongel - for Raspberry Pi - WiPi RPI Noir Camera Lab package ModMyPi YouTubeX Camera house in black plastic

I’m in Sweden so these might not be available everywhere, or more likely there are more options everywhere else.

So, I had the Raspberry Pi set up and running Raspbian. Now what?

Going back to my original crazy thought of being able to control a robotic hand from my smartphone for the purpose of squeezing squaky toys, I started abstracting the specific idea to being able to control an external, motorized device from a smartphone. In order to make progress toward that goal, I started breaking down the problem into manageable chunks.

One piece of the puzzle was the communication between a smartphone (in this case a Windows Phone) and the RasPi. Both are WiFi-enabled, so that solves basics. After a bit of searching, I found Brian Dorey's blog, where he describes a central heating control system, implemented with RasPi and Windows Phone. His solution was to use HTTP and run an Apache server on the RasPi, and having previously worked with both, it seems like a nice & simple solution. Since this part seemed straightforward, I decided to defer working on it to focus on areas I'm less familiar with.

Then there's the issue of a connection between the RasPi and an external device. This is where one of RasPi's exciting features, the GPIO (General Purpose Input/Output) connector, comes into play. Like the name suggests, you can plug external devices and move data in and out between them and RasPi through this interface. Thus, learning how to use the GPIO became a priority. Also, using the GPIO brings me to the area I'm most unfamiliar with: building component-level electronic systems, i.e. real hardware hacking.

There are tutorials available about the details of GPIO on Adafruit and a wonderful GPIO cheat sheet on ModMyPi, but I felt I needed a simple, practical project to really get my hands dirty with GPIO and circuitry. Thankfully, through ModMyPi I found the perfect thing to get started with: the BerryClip by Matt Hawkins. The BerryClip is a simple add-on board which plugs into the GPIO connector on the Raspberry Pi, and includes 6 LEDs, a buzzer and a button. The best part: assembly required. The kit ships as components, which need to be first soldered onto a printed circuit board, a PCB. So, the BerryClip would give me something to use through the GPIO, and also require me to get some soldering practice. With a cost of £5.99, I ordered one from ModMyPi.

A few days later, this hit my mailbox. Next post, assembling the BerryClip.

Much has already been written about using the Motorola Atrix Lapdock (essentially a portable HDMI monitor with a built in powered USB keyboard, trackpad and hub) coupled together with a Raspberry Pi. The Pi being powered by a micro USB makes it a suitable candidate for using it as a low powered portable computer.

You can still pick up a Motorola Atrix Lapdock for a lot less than it's original £300 or so selling price, although I've noticed that prices have started to creep up - expect to pay between £60-£80 for one. There is a newer Motorola Razr Lapdock available which I believe uses the same ports, so hopefully these very useful devices will continue to be produced and supported in the future.

This week my ModMyPi case finally arrived - it's an injection moulded click together case which is beautifully made -

I have already hacked together a cable to connect the lapdock and pi together - but I wanted to make a more portable and neater version. Plus using an HDMI micro adapter would provide a mount to hold the Pi in place, in the same way that a phone would be docked:

The lapdock provides a USB micro male, and HDMI micro male connector (note - micro not mini!). The USB provides power and data over 4 wires, and the HDMI video and sound. To marry this to your Pi you'll need to take the power connection to a male micro USB plug, and data to a male USB plug. Most people who've done this modification have also broken the power connection to the data plug as a precaution. In my version, I've included a power switch to make it easy to turn the Pi on and off - opening the lid of the Lapdock also cycles the power. Obviously this is all entirely at your own risk.

Here's my wiring diagram:

To do this you'll need:

A micro HDMI female to HDMI male adapter / MicroHDMI = HDMI "D type"

A micro USB female to male adapter (these are surprisingly difficult to find - ebay is often your friend here)

A regular USB female to Male cable (or you could use a micro USB male to USB male cable - I wanted the flexibility to use different lengths of cable)

A switch (Maplin or ebay) two or three pin on / off - just not momentary.

Something to use as a wiring box - the HDMI adapter holds the Pi in place quite nicely, so you could just wrap a bit of insulation tape round everything. I made a box out of a plastic screwdriver holder that came from poundland)

A wire stripper - these 'automatic' wire-strippers work well

Soldering iron and solder (soldering isn't too hard, but a lot of people are put off by the idea of it - a bulkier but soldering iron free alternative would be to use terminal blocks)

Craft knife

Epoxy glue

 First off you need to get the two micro adapters to fit together - check with the lapdock and carefully trim away the surrounding plastic until they both fit together. Then glue the two adapters together, whilst they're plugged into the lapdock. Be very careful not to glue them to the lapdock itself. Then expose the wires from the micro USB adapter - you might have to trim into the plug itself to do this. USB cables consist of red, black, white and green cables sometimes with a metal sleeve around them - you can cut the sleeve away and discard it. Be careful not to go through any of the wires themselves.

Here's the underside of the adapter - showing the two trimmed plugs side by side, glued together with epoxy - the wires from the USB adapter on the left feed into the box where all the connections are made:

Then cut your usb cable in half and expose the individual wires. Strip the ends of all your wires together. Then solder them together as per the diagram above. The power USB cable needs red and black connected - the data USB cable needs white, green and black connected. Put the switch on the red wire between the lapdock and USB power cable.

Once everything is soldered together, you can give it a quick test by plugging in the Pi to the lapdock. If everything goes ok, once the lid is open and you can boot and test the keyboard. If it doesn't work, check the connections and that the HDMI adapter is fully plugged in.

The final result is the Pi sitting on the lapdock behind the screen.

For extra neatness you could always mount the switch on the case itself and route all the cables internally, but there you go - a practical portable Pi Laptop you could just chuck in a bag and take with you, and that doesn't alter the lapdock in any way.

Thanks to Chipmonger on the Pi forums for the source of the cables and Arc Software for the wiring diagram.