Results 1 to 2 of 2
  1. #1
    75+ Posting Member
    Join Date
    Nov 2005
    Bombay, India VABB
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site

    HiPowered Autothrottle Servos using Simple H from Robotpower and hacked hitec servo

    HI -

    After a lot of experiments, I’ve had some success with my auto throttle – I have a original 747 200 quadrant, and therefore needed a heavier motor/servo to run the AT – basically, Ive used the Phidgets4motor servo, a hacked Hitec Servomotor and a Simple H amplifier. Using this, I can run a dc motor upto 24V/25A, controlled by FS2Phidgets

    Here’s what I needed:
    One Phidgets 4 motor servo card
    One hitec servomotor (does not matter which one, but I’ve used the HS815BB (what I really needed was the circuit and pot inside)
    One Robotpower Simple H amplifier - – great little device
    One 24V DC motor - (V and RPM depends on your linkage/gear/system)

    My main problem was that I needed a heavier motor to run my OEM throttles – the available options (as described on the forums) were to weak to do this – plus (most importantly), I needed to use FS2Phidhets to get the servo to talk to FS, and for calibration -

    I knew that the system works fine with the 815BB, I’ve tested it running with FS, and it tracks the AT correctly (as posted by many simmers) – the Hitec consists of a circuit board, a pot connected to the final output shaft, gears and a small dc motor – the leads from the Phidgets4motor servo and the onboard pot are connected internally to the Hitec circuit board. What I really needed to do was to use the output to the hitec motor and boost it to a higher voltage for the larger motor, and set the pot remote on the throttle lever for position.

    I cut the leads to the hitec motor and connected them to the input on the Simple H – the H sees this output as a variable voltage signal, and will boost it to any output (24V, 25A max) depending on the power you give to the Simple H independently.

    Next, I cut the leads to the pot, and set it remote on the #1 throttle lever, to track the position. The attached diagram shows the connections -you can also download it here:

    Configuration: (how I did it, each setup would be different) -

    Remove the motor from the gearbox assembly, keep it next to you @ the FS2P screen
    Attach pot to Throttle lever (say #1)
    Wire up the cards as per the diagram, and enable the Simple H with +5v
    Set the aircraft in-flight, say at FL10 – speed 250 – with AT on
    Set a max climb thrust, say 4000fpm @300Knots
    Verify that the onscreen FS throttles are at the max position, and the FS value (0 > +16384) is in the upper end values (use offset 089A and not 088C!)
    Note that the motor is turning
    Place throttle lever just 1/2 inch shy of the forward stop
    Adjust the Servo Range of Travel slider for the upper limit till the motor stops turning, ie, the error signal is null
    Next, set the aircraft into a decent where the on screen levers are at idle, and FS value is close to 0
    Note the motor turning in the opposite direction
    Set the throttle levers to 1/2 inch shy of the idle stop end
    Adjust the Servo Range of Travel slider for the lower limit till the motor stops turning, ie, error signal is null
    You have your Servo Range
    While re attaching the motor to the linkage, set max thrust in FS and place the levers to the forward position (1/2 inch shy, or till the motor stops turning) and then attach the motor to the linkage in that position – (you coud do this with FS at full idle as well) as long as the pot to throttle lever position remains fixed, this will hold -
    If needed, for safety, you can fix limit switches at either end of the throttle lever travel to cut out the motor, if for some reason there’s a spike somewhere.

    Using the Simple H frees you to use higher voltage motors, right upto 24V/20A continuous, and lets you use FS2P to control – in effect FS2P sees this rig as a Hitec Servo -



  2. Thanks Flying_Fox, Melnato, Kitsok, Photon thanked for this post
  3. #2
    75+ Posting Member
    Join Date
    Nov 2005
    Bombay, India VABB
    Contribute If you enjoy reading the
    content here, click the below
    image to support MyCockpit site.
    Click Here To Contribute To Our Site


    In Addition, you can use the Enable (EA, +5V) pin to power the motor on/off, depending on the AT state - This can be done easily using the FS2P logic function, and a relay or a digital out from a 0/16/16 or 8/8/8



Similar Threads

  1. 180 degree servo acts as 90 degress servo
    By ke6jzs in forum FS2Phidget Users
    Replies: 2
    Last Post: 04-03-2011, 05:11 PM
  2. OpenCockpits Servo Controller Board (with 2 x servos)
    By cjellwood in forum Off Site Articles For Sale
    Replies: 0
    Last Post: 09-11-2010, 08:36 AM
  3. Planning to start simple - not as simple as I thought!
    By Skylar in forum Where to Start Building a Home Cockpit
    Replies: 3
    Last Post: 01-12-2010, 04:47 AM
  4. Avsim hacked!
    By warvet in forum MyCockpit Crew Rest (Off topic chat forum)
    Replies: 1
    Last Post: 05-18-2009, 06:48 AM
  5. Bigger servos with "Servo 4-Motor"
    By drit in forum Phidgets & Cockpit Simulator Builder
    Replies: 4
    Last Post: 07-17-2004, 09:31 AM