dimanche 9 décembre 2007

i-SOBOT controller overview (2)

To finish with the controller top side, here is a first detail of the servo connections. Each servo is connected with 4 wires: battery supply for motor power(VCC in red), electronic supply (VDD in yellow, to be confirmed), signal (to be confirmed) and ground (GND in black). There are 2 extra signals on the head connector for LEDs.
Note header CON1 which is probably the programming connector for on-board chips.

On the other side of the board, we find the power section, the speaker amplifier and the gyroscope PCB.
The gyroscope is a Murata device. Package is similar to Gyrostar series but the reference C720 is not mentionned in the datasheet (www.murata.com/catalog/s42e.pdf). Assuming they are similar, this gyroscope measures rotation on axis along the longest side of the package. So the way the board is mounted in I-SOBOT, it measures rotation of its chest. I just don't understand why it is mounted on a daughter board, it could measure the same rotation mounted on the main PCB. Signal amplification (such as mentionned in the datasheet) is performed with a Unisonic Technologies LMV358L rail-to-rail operationnal amplifier(www.utc-ic.com/spec/LMV358.pdf).
Last thing we see clearly on this side, the 2mm pitch headers for servo connection.

Let's see how servos are wired to the dispatchers.
Note the star wiring for optimal power of each servo. Servos are wired in parallel from a dispatcher as shown on the picture below.
Each servo has four ultra flexible wires: red, green, blue and orange as mentionned by the letters R, G, B and O on the dispatcher. The meaning is:
Blue = GND = Battery -
Red = VCC = Battery +
Orange = VDD
Green = Signal

1 commentaire:


i am Gaurav Garg From ShareCash Downloader 2011 V13
i like your web site or all available content but i like this post the most..
thanks for providing this information in this open way..

Gaurav garg

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