samedi 26 mars 2016

Changing the LCD screen on a MC 505 Roland Groovestation

I own since few months a ROLAND MC 505 Groovestation.  I love this synth (YES ! it is a true synth not dedicated to DJs !!!) because there are a lot of knobs and buttons you can interact with.

Since I own this device, the LCD has some missing lines and dots, and that is because the original LCD screen from Roland is a very poor quality one.  So, after reading many posts about how to DIY, i did it, and that was not so much a pain...

You have to buy a LCD Display Character Module 2 lines / 16 characters, compatible with the HD44780 protocol.  You can find this kind of parts on Aliexpress for few euros, or around 10 euros with Europeans electronics resellers. 


Then you have to remove the existing one.  Start by unmounting the back cover :

You can see the LCD white flat cable, on the right of the two blacks.
Carefully unplug all flat cables using a small screw driver. Go slowly as sometimes it is not so easy. Do not force anything.

Then remove the motherboard. You must loosen all plastic bolts at the back of the MC 505 plus some screws. Again, stay cool !!  Plastic bolts are fragile.

So you should be here.  No you can push carefully on the window covering the LCD screen from the inside with a small plastic tool, then finish the job from the outside with the same plastic tool.  The LCD window is stuck with adhesive double sided tape. I prefer this aproach rather than trying to take off the window only from the outside at the risk of damaging the case.  More work, but less risks.

Then you have access to the LCD screws, and you can remove it.

As there is not enough room to place the generic LCD board, you will have to cut some small pieces of metal.  Use a metal saw blade. not cutting pliers !! And again, go slowly....

The schematic below shows the connection mapping between the generic LCD and the MC 505.
With a good solder iron, desolder the flat cable from the original LCD screen and resolder, wire by wire to a flat cable, like those used for IDE hard disk.

Before remounting you new LCD screen, make some tests with the contrast (screen tested and connected to the MC). It is possible you will have to change the 10K resistor value to another, depending on your screen ratio.

The final result with a blue LCD  :


dimanche 24 janvier 2016

Adding gamepads support to MXQ S805 Android TV box

I recently bought an Android TV BOX from a chinese vendor for less than 30 euros. The model is the MXQ one, embedding an Amlogic S805 quad core UC under Android 4.4 (kitkat).
Board model is "m201".

Connected via HDMI to a Samsung flat screen, I can say it does the job. I can browse my LAN with the 10/100M ethernet to watch HD movies , and that is much faster than using any WIFI connection. It also supports external NTFS USB2 hard drive.
Specifications :
  • Chipset: Am logic S805 Quad-Core Cortex-A5 at 1.5GHz
  • GPU: Quad-Core Mali-450 at 600MHz+
  • USB host: 4 High speed USB 2.0,support U DISK and USB HDD
  • Card reader: SD/SDHC/MMC cards
  • High Definition video output: SD/HD max.1920×1080 pixel
  • LAN: Ethernet:10/100M, standard RJ-45 / Wireless: Built in WiFi
  • HDMI: HDMI 1.4b with CEC / AV: Support / SPDIF/IEC958: Coaxial

I have installed the Archos Video Player app from the Google market. This small piece of software is perfect for the box, and much faster and simplier than the XBMC app on Android. It allows me to browse my SMB shares with a really cool GUI, designed especially for TV.

I own 2 PC Logitech cordless rumble pad,
so I wanted to use them with MAME, to play retro-games. But no luck. The Linux kernel of the beast doesn't include any game pad drivers, so Android apps can't see them. I tested also my Xbox 360 game pad : same result.

After a full kernel recompilation, I have now full gamepad support for both Logitech and Xbox gamepads !!

Hopefully, the box is pre-rooted, so you don't have to hack it to get superuser permissions.
Drivers can be loaded as module with the "insmod" shell command, in a terminal session (use adb or a terminal Android app). You must be in su mode.
for instance: 

insmod ff-memless.ko
insmod xpad.ko
insmod hid-logitech.ko

will load Xbox gamepads support (ff-memless is the force feedback driver) + HID Logitech support.

You have to install some "keylayout" to the /system/usr/keylayout directory if you want to use the gamepad to navigate in Android menu and applications.  The kl file maps gamepad events to keys events that Android will interpret. You can edit the mapping to build you customized controls.
To copy theses files , you must remount the system partition as writeable.

I made a zip pack containing all games pads drivers as ko modules I was able to compile with the kernel,  a set of keylayout. and a script to launch modules. I recommend to unzip on the /sdcard and to not modify system/lib.  Modules can be loaded from the sdcard.

To launch modules at each boot, you can use SManager (Script manager), an app on the market, and making the sh script to be "boot" and "root".  It is the most easy and safe way.

Download here
Enjoy !!

lundi 18 janvier 2016

Mon chappy 13F LB 50

Comme les vacances sont propices à la réflexion, ,et bien , je me suis acheté un nouveau jouet, fourni par un de mes amis, fana du modèle :  un chappy 13F LB 50, de 1981, entièrement d'origine.

J'ai eu le plaisir de l'essayer un peu avant : c'est assez fun à conduire, idéal pour les vacances au soleil !

L'étape suivante a consisté à chercher toute la documentation possible sur le web concernant ce modèle, en vue de quelques modifications et améliorations.

Comme d'habitude, on trouve beaucoup de petits rigolos pas très malins qui veulent se faire de l'argent en vendant les manuels techniques en PDF sur Ebay ou autre.  C'est super agaçant, mais on finit quand même par trouver ce que l'on cherche.  Alors pour vous éviter à votre tour de chercher pendant des heures, je mets à disposition tous ce que j'ai trouvé ici, en espérant n'enfreindre aucun copyright.

Bonne lecture.
Docs Chappy et autres 50 cm3 Yamaha

ODB2 on a 1999 BMW Z3 2 liters

Subject : Trying to connect an OBD2 diagnostic tool on my Z3;
Getting some errors when trying to connect to IKE and EWS.

The BMW diagnostic connector, 20 pins,  under the hood.
20 pin car OBD2 proprietary of BMW OBD II  vehicle diagnostic connector connector layout
used in all BMW models in 1988-2000's
Engine rotation speed
OBD-II diagnostic
Oil service and Inspection reset
External starter turn on
Battery power
ISO 9141-2 L Line
RXD- Diagnostic Data link
Ignition +12V
ISO 9141-2 K Line
Programming line
ISO 9141-2 K Line
TXD - Diagnostic data link

The specific BMW OBD-II pinout in the car :

16 pin J1962 OBD-2 car proprietary of BMW OBD-II diagnostic interface connector layout
used in all BMW models produced after 2000's
Ignition(in run or start)
chassis ground
Signal ground

ISO 9141-2 K-LINE
engine (ISO-9141 and ISO-14230), automatic transmission diagnostic (in some models)
ISO 9141-2 K-LINE
IKE/KOMBI, ABS, ABS/ASR, ABS/ABD, ESP, DSC, Airbag and other electronic equipment
(AFTER 2001 )
Engine rotation speed
Battery power

For BMW cars before 2001 having the OBD2 DLC in vehicle, as  shown on the above figure, it is not possible to acces the IKE, EWS, ABD, and maybe others modules because the “TXD” is not connected to the OBD2 plug.
Note that you need to close the cap of the 20 pins diag connector to establish the connection between TXD II and the OBD plug (the #17 and # 2 are connected when the cap is closed).   

If you are using some tools like BMW scanner, you will only be able to read the DME module, most of the time.
To enable the reading of all module FROM THE OBD2 in the vehicule, you have, with a thin wire, to brigde the 17 TXDII and 20 TXD and 2 on the 20 pins diag connector, or only bridge 17+20 and close the cap if the wire is thin enough.    Then, IKE, EWS and other modules become accessibles.

Volca Sample MIDI OUT mod - Step by step.

STEP 1 : Removing the back cover

. remove the battery cover
. remove batteries
. Unscrew the 7 screws as shown below


STEP 2 : Adding the mini-jack female connector


The picture above is showing how the mini jack female connector is attached to the Volca sample box.  BEFORE SOLDERING ANYTHING, you have to drill carefully a small hole, and make a flat surface inside the box with a “Dreymel like” tool.  GO Slowly.

Try to put the connector in place, with its locking ring, tighted by hand, then try to put the Volca box carefully.

I recommend to protect the PCB under the connector with insulating tape, to avoid tearing or rubbing the surface soldered components.


I don’t give any measure here as the connector you will get may be different than mine.
So, make your own measure with precision.


Once everything is ok, you can remove the connector, and solder the 3 wires on the connector.  I recommend to bend the connector pins against the connector box to facilitate the passage in the housing.  Put the connector in place, and tight ( not to much !!) the locking ring externally with a small pliers. 

STEP 3 : Soldering wires on the Volca PCB

. Locate the MIDI OUT print on the PCB : you will find 3 pads names GND, TX, VD
. Solder the 3 wires from the mini-jack connector on the PCB as shows the picture above

. Check connections with an  ohm-meter.  Ideally, use a male mini-jack inserted into the female connector to test point to point, from the PCB to the external mini-jack.

. Put the PCB in the case, carefully inserting the mini-jack connector between the two PCB, and screw the back cover.  Then take the time to print a nice “Midi Out” sticker to finish the job properly 

STEP 3 : Build a mini-jack to MIDI DIN 5 cable adaptor

You have to connect  : 
- TX (red) to the MIDI DIN PIN 5
- VD (white) to the MIDI DIN PIN 4
- GND (green) to the MIDI DIN PIN 2

Warning : do not use DIN 5 to mini-jack adapter sold on the web as they are not compatible with MIDI. 
 DIN-Adaptateur double coupleur à 5 pôles port/port 

You can also use a DIN5 female to DIN 5 female adapter to get a midi female DIN 5 for your Volca sample, connected to your cable.  You can make a short cable (e.g. 10 cm), for this kind of use.

The "mini-jack standard" allows us to get rapidly a MIDI THRU with this kind of splitter :
 Dexlan Doubleur adaptateur jack 3.5 mm stéréo Câble 15 cm

Build a second cable, and you get a MIDI THRU (in fact 2 OUT),  but use it with only one equipement in the MIDI THRU chain to avoid MIDI latency.
About MIDI OUT on the Volca Sample

  1. The MIDI clock is sent to any device connected to the MIDI OUT despite the chart above

  2. Know that the Volca Sample uses permanently 10 MIDI channels : one per part, as it is a sampler, and not a drums box.  You can play the part 1 on the channel 1, the part 2 on the channel 2, and so on..on the full range of an external keyboard connected to the midi in. On the other hand, the Volca sample will trig notes from parts to the MIDI OUT.  So, you have to set the global midi channel of other instruments connected upper # 10, to avoid “note on” effect.  For example, if I set my Microbrute to global channel 1 and want to use the internal step sequencer, the Volca “resets” the sequence by sending a “note on” from the part 1 to the synth (nb : i set the sequence reset from the Microbrute configuration software because I feel better like that !!).  Then I set the global channel to 11, and everything is working fine.

  3. The “motion capture” is not sent externally (e;g. when you turn the PAN knob when recording motion on a part) , but you can send CC from an external device.