Four new Raspberry Pi Zero add-on boards

January 18, 2016

Another bunch of new PCB’s. This time for the Raspberry Pi Zero.

RPI_PCBs_201601_small

In no particular order, there’s a serial RS232 board, a GVS I/O board with ULN2803 for servo’s etc., a Breakout board (I2C, SPI, UART and GPIO) and another MIDI interface ;-).

More details/info shortly.

As usually you’ll find them on our Tindie store.


Setting up RPi MIDI and Fluid Synth (SoftSynth)

December 13, 2015

The first part of this post are some instructions I wrote back in 2014 (more here)

NOTE: Setting the 31250 baud-rate this way only works for Raspbian kernel 3.18.11, the newer kernel Raspbian 4.xx has some issues.

Getting a MIDI 31250 Baud Rate on a Pi is not easy as it should be as 31250 is not a standard Pi baud-rate. But you can trick your Pi into it if you overclock (or rather underclock) the UART clock.

Start a terminal session and type:

sudo nano /boot/config.txt

Add these lines to the end of the file

# Change UART clock to 2441406 for MIDI 31250 baud rate
 
init_uart_clock=2441406
init_uart_baud=38400

save and exit.

Once saved reboot your Pi.

Next we need to stop the serial UART being used by Raspbian for the shell console. Check my previous post “MiniPIiio RS232 set-up” on how to do this.

Finally we need to add the following to “cmdline.txt”

bcm2708.uart_clock=3000000

 

Once we’ve done this we can get on with installing the MIDI UART driver and the SoftSynth.

  1. Check audio ports & levels
  2. Install MIDI UART driver
  3. Install SoftSynth
  4. Get MIDI IN talking to SoftSynth

Open up a terminal window and first..

 

1. Check audio ports and levels

Use HDMI audio for sound

amixer cset numid=3 2

Check the volume if needed

alsamixer

 

2. Install MIDI UART Driver

sudo apt-get install libasound2-dev
wget http://www.varal.org/ttymidi/ttymidi.tar.gz
tar -zxvf ttymidi.tar.gz
cd ttymidi/

We need to modify the make file for the Raspberry Pi, so lets

sudo nano Makefile

add -lpthread to line

gcc src/ttymidi.c -o ttymidi -lasound

so it looks like

gcc src/ttymidi.c -o ttymidi -lasound -lpthread

save file with “ctrl-x” and “Y”

Lets run the Make file and install binary

make

sudo make install

 

3. Install Fluidsynth

sudo apt-get install fluidsynth

err, that’s it just wait into it downloads and installs its self.

 

4. Get MIDI IN talking to SoftSynth

Start MIDI UART driver

ttymidi -s /dev/ttyAME0 -b 38400 &

Start the SoftSynth

fluidsynth --audio-driver=alsa /usr/share/sounds/sf2/FluidR3_GM.sf2

Check what devices they are listed as

aconnect -io

With device numbers connect MIDI IN to SoftSynth using “aconnect xx:x yy:y” for example:

aconnect 128:0 129:0

New RPi MIDI board and a new MIDI Breakout board

December 13, 2015

RPi_PIIO_MIDI_PCB

I should have called this post “yet-another RPi MIDI board” as it’s includes my third iteration of a MIDI interface for the Pi. But YARMB doesn’t actually trip off the tongue :-)

So here we have a new RPi MIDI board. Briefly its spec is:

  • MIDI IN via 5-W DIN Connector
  • MIDI OUT via 5-W DIN Connector
  • 3.3V Operation
  • HAT foot print (65 x 56mm).
  • Four fixing holes.
  • ID EEPROM (not fitted)

 

In addition to the RPi MIDI, there’s also a MIDI break out board (BoB) board. It’s spec is:

  • MIDI IN via 5-W DIN Connector
  • MIDI OUT via 5-W DIN Connector
  • MIDI THRU via 5-W DIN Connector
  • On board 5V Voltage Regulator
  • Size 80 x 49mm.
  • Four fixing holes.

 


DIY micro USB Hub for Raspberry Pi Zero

December 4, 2015

After ordering the new Raspberry Pi Zero I suddenly realised I didn’t have a suitable micro USB cable adapter to connect either a keyboard or mouse to it. Now common sense would have been to go back on-line and order either suitable cables or a suitable micro USB hub but as the maker saying goes “necessity being the mother of invention” so I decide to make my own. In this case a non-powered micro USB hub.USB_Bits

Getting the base components was easy. A quick call into a “pound” (or the equivalent dollar, euro etc.) shop got me a micro USB data/charging cable and a USB hub as shown for the princely sum of £2.

Tools

The basic tools are:

Cutter
Screwdriver (flat and/or Philips)
Wire Strippers
Scalpel/Small knife
Soldering Iron
Solder

 

Open USB Hub case

USBHub OpenUSBHub_PCB

Depending on the screws used in the USB Hub case you may need a Philips screwdriver to open the plastic USB Hub enclosure. In my case, the Hub’s plastic enclosure was clipped together and a bit of squeezing and gentle persuading with a flat bladed screw driver saw it come apart.

 

De-solder USB Cable

USBHub_Desolder_Wires

Once the USB hub is apart you should see a small PCB with a number of USB connectors and a cable. Make a note of the wire colour and positions. De-solder the existing USB wires from the PCB. Carefully apply heat from the soldering iron to the soldered wire and when the solder melts, gently lift the wire away from the PCB pad.

 

Prepare micro USB cable

MicroUSB_Cable

MicroUSB_Cut_Cable

MicroUSB_Strip_Wires

With the wire cutters, cut the USB A connector (the bigger of the two USB connectors) off the cable. With the wire cutters or a small knife/scalpel cut back and remove about 2cm of the external cable insulation. Using the wire strippers, strip about 5mm of insulation from each of the individual wires. Finally, for each wire twist the copper strands and using the soldering iron, “tin” them and repeat for all wires.

 

Soldering the new cable

USBHub_Solder_WiresUSBHub_Wires

Remembering to use the info from the note you made earlier ;-), match the wire colour’s to the PCB pad and solder the first of the new wires from the micro USB cable back on to the USB Hub PCB. Repeat this for each of the wires in the micro USB cable. Once finished, check your work for any solder bridges and/or dry joins.

 

Putting it back together

Once you’re soldered all the wires back on the USB Hub PCB, reassemble it back into its plastic enclosure. You may want to add a tye-wrap to act as a strain relief for the micro USB cable.

MicroUSB_ReAssembleUSBHub_Finished

FIN


Raspberry Pi Zero != Zero but only £4 !!

November 29, 2015

Waking up on Thursday morning I didn’t expect to find a new version of the Raspberry Pi in the wild, let alone a new version which only cost £4 (~$6). The Raspberry Pi foundation are almost as tight lipped as Apple when it comes to new product announcements ;-)

There were reportedly 10,000 units made but at £4 it sold out quickly on all the online sites. It you were lucky to find a copy, it was free with this months edition of the MagPi magazine. It must be the first time you bought a computer magazine and actually got a free computer !!

R-Kade Proto5_4buttons

Spec wise, it’s basically a slightly faster version of the rev2 Raspberry Pi A & B but in a much smaller outline (65 x 30mm). It uses a 1GHz BCM2835, with 512MB of RAM, micro HDMI for video, micro USB for data and micro USB for power. All great except I think the choice of a micro USB for data is a mistake. You lose the advantage of the new smaller size and price point by needing a USB A to micro USB adapter or cable to connect keyboards, mice and WIFI dongles.

At 65 x 30mm makes it an great choice for many a small projects. At this size, it has allowed me to dust off a couple of retro gaming projects I’ve had sitting on the shelve.

I’ve ordered a couple so just waiting now for new stock at Farnell then I can add it to my every growing pile of Pi’s.

In the mean time you can check out the announcement here:

https://www.raspberrypi.org/blog/raspberry-pi-zero/


Son of R-Kade update

October 31, 2015

After five or so prototypes, I’ve finally arrived at a mini cabinet shape I’m happy with. The last few prototypes were made to experiment with the optimum viewing angle for the display, but I think I’ve got that right now.

R-Kade Proto5_4buttons

R-Kade Prototypes
Full size arcade joystick and buttons are a little too big for the mini cabinet so I’ve decided to go with a mini joystick and 16mm push buttons.

One of the design features I’m going for, is to have swappable control plates. I’ve mocked up a couple of control plates with various button combinations as well as a control plate with full size arcade joysticks and buttons.

R-Kade Control Plates
The next step is to cut the cabinet design from 6mm plywood and see how that looks.


Son of R-Kade

September 29, 2015

Sequels are always an interesting proposition. Some are as good or better than the original, for me the film Aliens is a great example of this. Some sequels take things in a different direction, again I’ll use Aliens as an example for this: action vs. horror. But in reality most sequels are just pants :-)

R-Kade_eDay4_1_small
So when the Raspberry Pi foundation announced their 7″ Touch LCD Screen, I knew I wanted to make a sequel to my Raspberry Pi powered bar top arcade cabinet: R-Kade.

I designed R-Kade for the Raspberry Pi way back in December 2012 after wanting to build an Arcade Cabinet but never having the space for a full size cab and the Pi’s small size offered me a chance to make something on a smaller scale. It was built it in early 2013 and took it to the Maker Faire UK in Newcastle in April of that year. It’s been to every Maker Faire UK since, Edinburgh Mini Maker Fire twice, eDay three times and numerous other maker events. I finally got around to updating its wiring earlier this year by designing and making “ArcadeIO”, an joystick and button input interface HAT-like board. Whilst it is built like a tank and has taken almost every abuse the eager punters have thrown at it, it was always a big and cumbersome thing to carry to events. So with new 7″ LCD in hand here goes…

opening sequence:

Son of R-Kade

R-Kade7_1_small

R-Kade7_2_small

p.s. Here’s hoping its not as bad as Phantom Menace (oh wait a minute that was that a prequel)


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