USB Joystick Interface

Discussion in 'Embedded Systems and Microcontrollers' started by monster_catfish, Mar 20, 2011.

  1. monster_catfish

    Thread Starter Active Member

    Mar 17, 2011
    This is my first post here, so I'll try not to make a total fool of myself. Summing up, I plan to construct a throttle quadrant for my heavy metal flight sim sessions.

    It will comprise six potentiometers, and six buttons, for the functionality of twin throttles with dual thrust reversers ( triggered by momentary on switches ), along with stab trim, rudder trim, speed-brakes, and flaps.

    If all goes well with the metal work, I also intend to add dual TOGA buttons, and dual Autothrust Disengage buttons, with each pair run through OR gates.

    After a long internet search, I found a schematic that is close in functionality to what I seek, and which I hope to modify to suit my configuration. Here is the link to the schematic I located :

    I held out reasonable hope that this project could be a success, until I took one look at the 38 pages of program code that was needed to get the joystick in the above link USB readable, at which point the wind definitely dropped out of the sails for me.

    As an engineering undergraduate back when dinasaurs roamed the earth, I dabbled with 8085 assembly language, but that shallow knowledge was of no help at all as I tried to make head or tail of the code used by the author of the project in the above link.

    I am writing here to see if there is anyone who might be aware of pre-written code packages that could be modified by a bone-head like me, and used to interface my planned throttle quadrant with USB protocol. I have enclosed the slightly modified version of the schematic I would like to use, in case that might help narrow down the options that would work for this idea.

    The non-inverting opamp amplifiers I included in my schematic adaptation are there because the 100K linear single turn pots on all the levers will only get about 60 degrees of travel from the lever articulations, and I want to be sure that a full 0 to 5 volt output is produced from each pot. Finally, I intend to use an ATMEga8 chip, which has identical pinouts to the one shown in the schematic.
    Last edited: Mar 20, 2011
  2. monster_catfish

    Thread Starter Active Member

    Mar 17, 2011
    Finally, thanks to a more patient archive search here, I stumbled on a pre-wired, programable HID-USB interface board which comes with the capacity for 50 joystick inputs, that may be either analog pots, or buttons. Talk about having Eureka moment...

    I instantly mothballed by DIY plans in the above thread, deciding not to re-invent the wheel, even though the pre-fabricated board is a bit steep at $79 a pop, as opposed to the total parts tally of $25 that the DIY board would have cost. After a moment of thought, I figured the extra $50 I'll be shelling out for this ready-to-use HID-USB interface module is still preferable to getting lost in a sea of code without a paddle, had I opted for the DIY route.

    To the guy who posted the link I copied below, I tip my hat and offer my sincere thanks. And fer sure before I ask any future questions here, I'll wear out that search button BEFORE waving the white flag.