With the new Myo Connect update, we added support for the scroll wheel. This was really all that was missing from my Mouse Control Script (grab it in the Myo Market now), so for this week's #MyoCraft I thought I'd add it in. Check it out:

  
scriptId = 'com.undercoveryeti.ultimatemousecontrol'  
    scriptTitle = "Ultimate Mouse Control"  
    scriptDetailsUrl = "https://market.myo.com/app/557af681e4b0910e1dcf8482"

    -- Set this to false to disable automatic locking when your arm is down at your side
    DROPLOCK = true

    -- Set this to false to disable vibration feedback, or just comment out notifyUser calls in places you really don't want it.
    HAPTIC_FEEDBACK = true

    SCROLL_ACCELERATION_RATE = 2  
    SCROLL_INTERVAL = 100  
    scrolling = 0

    description = [[  
    Mouse Control Script

    Control the mouse with your Myo armband! If you want this to be on all the time, make sure you put this at the BOTTOM of your Application Manager list, or nothing else will work. 

    If you would like this to only work for certain applications, follow the directions in onForegroundWindowChange.

    If you don't like the droplock behaviour, disable it by setting DROPLOCK = false

    Questions or problems? Talk to us (@thalmicdev)  
    ]]

    link = [[ ]]

    controls = [[  
    Controls:  
     - Move arm to control mouse
     - Fist to left click
     - Fingers spread to right click
     - Wave in scroll down
     - Wave out to scroll up
     - Double tap to enable or disable cursor control
     - Drop your arm to your side to disable control
     ]]

    knownIssues = [[  
     ]]

    function notifyUser(edge)  
        if (HAPTIC_FEEDBACK and edge == "down") then
            myo.notifyUserAction()
        end
    end

    function leftClick(edge)  
        notifyUser(edge)
        myo.mouse("left",edge)
    end

    function rightClick(edge)  
        notifyUser(edge)
        myo.mouse("right",edge)
    end

    function scrollUp(edge)  
        notifyUser(edge)
        scrolling = edge == "down" and 1 or 0
        scrollAcceleration = 0
    end

    function scrollDown(edge)  
        notifyUser(edge)
        scrolling = edge == "down" and -1 or 0
        scrollAcceleration = 0
    end

    function lockMyo(edge)  
        myo.controlMouse(false)
        myo.lock()
    end

     STANDARD_BINDINGS = {
        fist            = leftClick,
        fingersSpread   = rightClick,
        waveOut         = scrollUp,
        waveIn          = scrollDown,
        doubleTap       = lockMyo
    }
    --STANDARD_BINDINGS = true

    bindings = STANDARD_BINDINGS

    function onForegroundWindowChange(app, title)  
        -- To make this work for a specific application rather than all applications, take these steps:

        -- 1) Delete the following line
        return true

        -- 2) Uncomment (ie, delete -- from) the following line.
        --myo.debug(app)

        -- 3) Load your script into the Application Manager
        -- 4) Turn on Developer Mode in Myo Connect -> Preferences
        -- 5) Open the application you want to control
            -- You should see something pop up in the Myo Debug console along the lines of
            -- something.exe
            -- on Windows, or 
            -- com.something.somethingelse
            -- on Mac. EG: Powerpoint will show you:
            -- POWERPNT.EXE
            -- or
            -- com.microsoft.Powerpoint
        -- 6) Copy and paste the line for your app, and replace YOUR_APP_HERE (leaving the quotes) in the following line
        --return app == "YOUR_APP_HERE"

        -- 8) Turn off developer mode, comment out or delete the myo.debug line from step 2, and save and reload your script in the Application Manager. Done!

        -- OPTIONAL
        -- Get stuck or want to do more? Try this tutorial series:
        -- https://www.thalmic.com/blog/myo-script-tutorial-roundup/
    end

    function onPeriodic()  
        deltaTime = myo.getTimeMilliseconds() - lastScrollTime
        if (scrolling ~= 0 and deltaTime > SCROLL_INTERVAL - scrollAcceleration) then
            lastScrollTime = myo.getTimeMilliseconds()
            myo.mouseScrollBy(scrolling)
            scrollAcceleration = scrollAcceleration + SCROLL_ACCELERATION_RATE;
        end

        if (DROPLOCK and myo.isUnlocked() and myo.getPitch() < -1) then
            lockMyo();
        end
    end

    function activeAppName()  
        return scriptTitle
    end

    function onUnlock()  
        myo.unlock("hold")
        myo.controlMouse(true)
    end

    function onPoseEdge(pose, edge)  
        --pose = conditionallySwapWave(pose)
        --myo.debug("onPoseEdge: " .. pose .. ": " .. edge)
        fn = bindings[pose]
        if fn then
            keyEdge = edge == "off" and "up" or "down"
            fn(keyEdge)
        end
    end  

You can see I also snuck in my own drop-lock mechanism. To make it easier to turn off mouse control when you aren't using it, you simply drop your arm down to your side and the Myo armband locks automatically. You can disable that by setting DROPLOCK = false, but I quite like it.

That's it for #MyoCraft! Don't forget to submit your ideas to MyoCraft@thalmic.com.

Otherwise, see you next week!