Monthly Archives: November 2018

Stand for Hannspree 13.3″ Tablet

I use a Hannspree 13.3″ Android tablet to store and display sheet music. It runs the excellent “MobileSheets” app that allows me to store PDF files of sheet music scans and store them in an indexed database. THe Hannspree tablet was about the largest screen I could find at the time. It’s not bad and nearly A4 size and so not too strenuous on the eyes.

I tried to find an adaptor to mount it on a photography tripod but they all seem too small for the tablet. I had to build one myself. Its not too hard. I found a scrap of plastic extrusion that had a channel to hold the bottom of the tablet and mounted this on a piece of wood. The top of tablet is held in place with a large padded washer and a wing nut. I used a spare table leg bracket to attach the wooden piece to the tripod. The tripod I have has a detachable bracket which has a bolt that screws into the table leg bracket.

Jobs a good’un ……

Front view of holder. The squares are pieces of felt padding.



Rear view of holder with attached tripod mount piece.

Tablet mounted on tripod running MobileSheets.



New Yamaha PSR S775 with MIDI mate

PSR S775

I have bought myself a Yamaha PSR S775 as an early christmas present. (But really for starting up a functions duo). This is the flagship “arranger” keyboard that has lots of realistic voices, auto accompaniment, USB interface, MIDI record/play and MP3 record/play.

I decided to buy this keyboard to replace the defunct BK7M (spit!!) and upgrade from an earlier Yamaha arranger keyboard that I bought in 1993. (and still works!!) The PSR 6000 was very good at the time and I used it successfully in a functions duo (keyboard/vocals, guitar/vocals). It unfortunately had a floppy disk drive to save and restore registrations and there was not enough memory to hold everything required for a gig. This meant that there was a frantic swapping of floppy disks during the gig.


Now, with a 25 year interval, you would have thought that the latest keyboard would be best in all respects, but it is not necessarily the case …..

Here are my Pros and Cons :-

  1. Obviously with better technology there is more memory, more and better voices and everything can be stored on a USB stick. [+]
  2. The S775 buttons are much smaller and spongier. There is too much use of LEDs behind the buttons so it looks like a christmas tree. The PSR6000 had nice thumb wheels to change parameters whereas the S775 has fiddly up/down buttons. The PSR775 parameter selection wheel has a really cheap feel to it. [-]
  3. The PSR6000 has nice rounded corners, looks more robust and is more appealing to look at. There is more space used for the controls. [-]
  4. The PSRS775 has two “live control” knobs to adjust effects on the fly. [+]
  5. The auto accompany function and styles has not really changed at all. The S775 can store a lot more styles.
  6. The keyboard size and touch is identical.
  7. The pitch change and modulation wheels on the S775 are not as good as the PSR6000. [-]
  8. I think that the layout and ergonomics are better on the PSR6000. [-]
  9. The music stand is the most cheap and nasty thing ever. Obviously just an after thought. [-]

Overall the technology has improved, but little consideration has been paid to ergonomics and style !!

Anyhow the keyboard sounds as cheesy as its predecessor and you soon get tired of the novelty of the styles. However, it is ideal for the function gig either as a one man band or a duo.


It didn’t take me long to hook up my Yamaha P120 electronic piano using a midi cable in order to provide a wider and touch weighted keyboard.

It didn’t take me long also to realise that a “MIDI mate” would allow me to have two keyboard setups with different sounds. So I have written some firmware for my “MIDI mate” that allows me to some nifty functions by simply pressing keys on the keypad.


Midi Mate with keypad

The MIDI mate is connected in between the Piano and the S775 using standard MIDI cables. No battery or power is required, as it is able to obtain a small amount of power from the MIDI interface. The next picture shows the insides. I have used my AK47M pcb. You can see it is sparsly populated with one microcontroller chip a capacitor and 5 resistors.


The next picture shows my keyboard setup with the “Midi Mate” in place. There is also a screenshot of the MIDI configuration required on the PSR S775 :-

The nifty functions are as follows :-

  1. Press the “#” key and the piano keyboard duplicates the PSR S775 keyboard.
  2. Press the “*” key and the entire piano keyboard is independent to the S775 keyboard.
  3. Press keys “1” to “9” and a right hand voice is selected independent to the S775 keyboard. e.g 1=piano 4=strings 5=jazz organ. The piano keyboard is split so that the left hand can control the auto accompany.
  4. Press key “0” followed by two digit number to select a voice as in (3). The voice is stored for key press “9”.¬† Press key “0” three times to double up last two voice selections.

Function “4” may change as I explore what works.

This works really well by having a basic pallette of solo instruments on the piano keyboard and being able to swap quickly without any fiddling about. It also means I have a decent keyboard to play and plenty of space for the auto accompany left hand.


I mentioned the music stand was tacky – well this is what I meant ……

The Real book causes it to wobble like a demented penguin.



AK47M project part 10 (Prototype ready)

I have completed the prototype AK47M and the first versions of firmware and controller software. I used an old cigar box as the enclosure. I have tested the unit using my Yamaha electronic piano and a keyboard amplifier. It works as expected and I am currently  writing a user manual which will explain the operation in greater detail.

The front panel is a piece of laminated paper glued onto some thin MDF. The front panel comprises of a 3×4 keypad, a 2 line LCD display and a row of 4 push buttons.


On the back is from left to right:

  1. The USB power cable.
  2. A pair of jack sockets for the stereo output for the auto accompany synth.
  3. A pair of jack sockets for the stereo output for the solo (right hand) synth.
  4. A 5 way DIN socket for the MIDI input

The following shows a series of screen shots of the AK47 LIVE software that either runs on a Windows PC or the internal Raspberry PI on-board computer.

The windows version simulates the keypad using the PC numeric keypad.


This is the initial screen with control for the solo lead voices and the left right hand split.

The buttons along the bottom deal with navigating the performance file and editing the current performance file.

The green boxes allow for easy selection of a voice for a part. The blue boxes are volume control sliders.


These two screens control the selected style parameter. The style file assigned to the current performance is shown in red text. The individual style parts may be independently controlled

This screen shows the BIAB file selection and the BIAB editor with a chord sequence for “Ain’t Misbehavin”