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  • Servo Hawk Control Board

      Directly and independently control up to 8 standard servos with the Servo Hawk . There are also 7 switching type outputs capable of switching devices up to 30v and 500mA including transient suppression facilities for those inductive devices (such as motors, solenoids and relays)

    Servos are rotational devices that allow the angular position of rotation to be specified. Once specified the servo will “hold” that position against external forces. The way the position is specified is by supplying a variable width pulse at regular intervals. The width of the pulse determines the angular position. The accepted standard for the pulse width is to have the centre position defined by a width of 1.5ms , the extreme anti-clockwise position as 1.0ms and the extreme clockwise position as 2.0ms. The vast majority of servos adhere to this standard although the amount of rotation corresponding to extreme clockwise or anti-clockwise varies according to the servo design. Typically this ranges from +/-90 degrees to almost +/- 180 degrees with the most common ones falling somewhere in between.

    Servos are also fairly standard in the type of connector they use for connecting the servo to the controller (eg servo hawk), especially the hobbyist RC servo type. The connector is a three way socket as shown on the right. The three wires are usually (but not always) coloured black, red and yellow. The black wire is the ground (or common), the yellow is the pulse width modulated signal for position control and the red is the power supply positive terminal connection. i.e. apart from the pulse width signal that tells the servo where to move to, it also requires its own power source for driving its internal motor and control circuitry. The voltage and current requirements of the servo power supply will vary from servo to servo with the ones producing the highest torque having the highest current requirements. To accommodate this variability, servo hawk does not supply any power to the servo. It simply provides a convenient way of connecting an external power source to all eight servos that it controls. Servo Hawk provides 8 connection points for taking the standard three way connector from each of the eight servos that it will control. The control signals are “driven” by the on-board microcontroller whilst the power connections (the black and red wires) are simply routed to a pair of screw terminals where the external servo power supply can be connected. Although most servos only require a few hundred milli-amps the power connections can handle up to 5A, which would accommodate even very high specification servos

    As mentioned above, connecting a servo to the Servo Hawk is simply a matter of plugging in the standard three way socket attached to the servo to one of the eight on board three pin header connections. The header connections are labelled Servo 1 to Servo 8. Up to 8 servos can be connected to the Servo hawk at any one time, with identification of an individual servo on a given board by the number of the header it is connected to. Always check the specifications of the servo you are connecting to make sure the socket has the same pin configuration as the on board header (i.e the standard servo connection).

    Once your servos are connected you also need to connect the servo power supply to the terminal block labelled “Servo Power”. This will distribute the power to each of the connected servos. The servo power supply ground (or negative) terminal should be connected to one of the terminals marked “GND” and the positive terminal of the power supply to the “V+” terminal.

    In addition to the servo outputs on the servo hawk there are 7 high voltage switching outputs. These allow a wide range of relatively low power DC devices to be controlled in addition to the servos. These devices can be any DC operated device with a current requirement of less than 500mA and a voltage of less than 30v. Many useful devices can be used here including DC motors, solenoids and the very useful relays, allowing switching of even larger and more powerful devices.

    Connecting these devices simply requires a common ground connection with the device being connected between the output and the positive terminal of an external power supply chosen to match the devices characteristics for voltage and current. This is illustrated below.

    Software and Programming:   The Hawkeye software, supplied with the board, provides a PC based application allowing full control of all facilities on the Servo Hawk including the position of all servos. This, in itself, provides a very useful control facility which can be applied to a wide range of projects.

    However, the real power of the board becomes available when it provides those facilities to the programmer writing his own control software using the supplied DLL function library. This DLL allows user programs written in a wide range of languages (eg C, C++ and Visual Basic), to have easy access to it's facilities. This gives the programmer simple to use functions like ..

    Sys_Initialise( )

    Servo_SetServos(BoardNumber, Servo1Position, Servo2Position, ..... Servo8Position)

    Servo_SetOutputs(BoardNumber, Outputs)

    .. rather than having to address the tricky USB comms protocols. Multiple hawk boards of any type on the same PC are automatically accommodated and made available by a simple board number allocation.

    More information on programming in Visual Basic and also in C++ is available within the manual, which may be downloaded below. .

    (Note: This is not a "kit of parts" , it is fully assembled and tested)

    Compatible with Windows XP, Vista, 7, 8 and 10
        To download a copy of the user manual for this board, right click on the link on the right and choose "save target as". This will allow you to download a PDF copy of the manual

        You will need Adobe Reader installed on your PC to read this document. Adobe reader is available for free download from Adobe using the link to the right..

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