Parallax Stingray Manual page 20

Battery Pack Socket [ 8 ] and Barrel Jack Connector [ 9 ]
The Battery Pack Socket accepts the connector on the Stingray
Battery Pack. The Barrel Jack Connector is for use with a 6-15 VDC
wall-mount power supply, with a center positive 2.1 mm barrel
connector. NOTE: Using the Barrel Jack Connector temporarily
disables the Battery Pack Socket.
CAUTION: The input voltage (VIN) is also the motor voltage.
For this reason you should not use a wall adapter or battery higher
than 7.5 VDC when enabling the motors (power switch moved to the
third (right) position, see below). Voltages higher than 7.5 VDC can
severely reduce the life of the motors and potentially damage them.
Power Good/Fail Indicator LEDs [ 10 ]
There are actually two LEDs for power indication on the control board, one red and one green (see the
figure above). The green LED means the power is good. If the input voltage falls below approximately 6
VDC the green LED goes out and the red LED above it comes on. You may also notice when switching the
power on/off that the red LED briefly blinks while the power supply rails stabilize.
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3-position Power Switch [ 13 ]
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Headers to 24 Available I/O Pins (P0 – P23) [ 14 ]; Voltage Translators [ 15 ]
The 24 available I/O pins are connected to three TXB0108 8-bit bidirectional voltage level translators that
convert the voltage from 3.3 V at the Propeller chip to 5 V at the I/O headers and provides some short
circuit protection with built-in 4 kΩ resistors. These fully bidirectional pins are grouped as three ports with
eight I/O lines each: P0–P7, P8–P15 and P16–P23.
Copyright © Parallax Inc.
LT3501-based Dual Switching Supply [ 11 ]
The power supply uses the LT3501 Dual Tracking 3 A Switching Regulator
to provide the 3.3 V and 5 V used on the control board. This supply
regulates the 6 – 15 VDC on the input down to the desired voltages at up
to 3 A of current per supply.
Reset Button [12]
This button resets the Propeller chip, initiating its boot up procedure (see
the Propeller Help). Be aware that if the motors are running, this will cause
them to go into brake mode (see Table 1 on page 19).
The first (left) position, marked ALL OFF, turns off power to the Control Board, I/O
headers when set to 5 V, and motors. In this position the power LED is out. The
second (middle) position, marked POWER ON / MOTORS OFF, turns on power to the
control board and I/O headers, but disables the H-Bridge, effectively turning the
motors off. The last (right) position on the power switch, marked POWER ON /
MOTORS ON, turns on power to the control board, I/O headers and motors. Note
that the 3-position switch has no effect on VIN availability at the I/O headers set to
VIN, nor at the VIN power supply tap (see VIN, 5 V, and 3.3 V Power Access
Headers [ 17 ] on page 21).
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Stingray Robot (#28980)
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v1.1 10/6/2009 Page 20 of 26