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[Frakk]

Senator, if we're using the original layout we dont need the supply pins. I just thought it would be a nice feature for additional things like switches with leds or additional parts on a dashboard.

George, the variable pot besides the analog inputs is for the analog reference voltage adjustment. In the original design Vcc or 5V is the only reference which limits the inputs. With this adjustment you can turn a 270deg pot into 90deg or whatever you need, without loosing resolution.

[Senetor]

Frakk,
the MJoy16 gets it's power from the USB port on the computer, and can only supply between 100 to 500 milliamps, depending on the port, so it is not a good idea to power LED's and extra switches from it. You are better to supply your extra devices from another power source that can handle the extra load.

Regards Senetor.

[Frakk]

500mA is still enough for a lot of applications. I agree that a lot of ppl wont really need it and an external supply is a better choice. Time and testing in simulators will tell if it is really needed or not. Others please add your opinion too.

[Senetor]

All in One, measures 143mm x 86mm.

Regards Senetor.

[Frakk]

Looking good! Now its time to build and test it! I will be getting the parts soon to hook it up on a protoboard, hopefully I can make the board too.

[GeorgeBoles]

Hello Chaps,

I have not quite got my head around the "diodes and matrix" thing. I am just trusting everyone's advice.

I have been busy designing my version of the project. I am going to have to use mainly hard-wiring of the switches in my old CH Joystick and throttle (otherwise there will be too many wires between the joystick and the throttle), but I will have the option of a smaller matrix for later additions.

My question:

On the matrix diagram it appears that the diodes only go on the "columns", with the anode of the

diode facing the column and cathode facing the switch. In other words the diode comes on the postive

side of the switch, like this:

Column --- (+Diode-) ------- Switch ------ Row (As in Mindaugas' original diagram)


Does it matter if I put the diode on the "negative" side of the switch does it, as long as the diodes

are still "anode to Column" and "Cathode to Row"? Or like this:

Column --- Switch------- (+Diode-) ------ Row


Would this option work, or would I get "phantom" button presses coming up?

All advice greatfully appreciated,

Regards,
George

[Frakk]

Hi George

The position of the diodes doesn't matter, only the polarity. The matrix key system is basically a scanning operation. The IC progressively outputs a voltage (high) on the columns, and scans on the row's for any high input. If a voltage input is detected, it records the column that the output was high on, and the row that the input came in at that particular moment. These two numbers define the exact switch that was pressed and this data will be sent to the pc. The diodes will prevent any reversed voltage and current, and also introduce a .7V forward drop to block any noise and interference under this voltage.

[Senetor]

Here's a couple of diagrams,

Regards Senetor.

[Senetor]

All in One MJoy16-16

Updated 11-6-2009

Here are the files.

MJoy16-16 All in One Project.pdf

(450.51 KiB) Downloaded 1174 times

MJoy16-16 All in One Project PCB.pdf

(53.77 KiB) Downloaded 922 times

Rows and Columns.pdf

(172.05 KiB) Downloaded 800 times

MJoy16-16 All in One.rar

(56.66 KiB) Downloaded 701 times

MJoy16-C1 Users Manual.part1.rar

(200 KiB) Downloaded 681 times

MJoy16-C1 Users Manual.part2.rar

(98.02 KiB) Downloaded 610 times

Programming MJoy16.pdf

(196.42 KiB) Downloaded 1112 times

MJoy16-16 Hex v1.3.zip

(7.5 KiB) Downloaded 693 times

Regards Senetor.

[GeorgeBoles]

Hi Folks,

This is my project as attached. The board sits within my CH Pro Throttle base. The top 15 pin Dsub takes information from my CH F-16 Fighterstick, the lower one takes information from my rudder pedals and up to 25 other buttons (none of which I have) and the other connectors take the information from the Throttle itself. I think the wiring is correct, but if anyone would like to check it I would appreciate it. (I have yet to join the Ground wire to the USB pins. I also have to put in jumpers to cope with Centre, Mode, and and On/Off button - the last one so that I do not have to connect/disconnect the USB port to work the initialize and re-centre functions.)

I am going to have little flying jumpers (made from ribbon cable) for many of the connections from the 15 pin Dsub connections, especially if I stay with a single sided board.

As for the diodes, you are saying that they are just to help eliminate little spikes as buttons are pressed and released? That would make sense, because otherwise I could see no "logical" reason that we should need them. (Edit: see later posts. The diodes and some "hidden" 10k resistors are very important)

Regards,
George.