20) Infrared Receiver Sockets (IR RX)
There are four 3-pin IR Receiver sockets spaced around the front edges of the SumoBot
PCB. Each turned-pin style socket with 0.1” pitch is compatible with the Infrared
Receivers (#350-00039) included in the SumoBot WX Competition Kit.
Each socket has 5V, GND, and an I/O pin connection for the IR receiver to send data to
the Propeller. The center GND pin is identified by a logo representing the IR receiver,
which shows the correct orientation for the receiver.
21) Infrared Transmitter Sockets (IR TX)
There are four 2-pin Infrared transmitter sockets spaced around the front edges of the
SumoBot PCB. Each is a turned-pin style socket with 0.1” pitch, compatible with the
Parallax IR Transmitter LEDs (#350-00003) included in the SumoBot WX Competition
Kit.
Each socket has a PWM-GND and an I/O pin connection for the Propeller to supply a
voltage signal to the IR Transmitter LED.
The PWM-GND pin is a special feature of the SumoBot WX, and enables fine control
over the IR TX LED brightness. Refer to the PWM-GND Op-Amp description below and
the schematic download at the SumoBot WX product page for more details.
22) PWM-GND Op-Amp
The four IR TX LEDs have a common GND connection controlled by an onboard
Op-Amp to allow fine control over the LED brightness and therefore IR receiver range.
To use the LEDs you must either set P23 low (for maximum brightness), or use PWM
code to set the voltage level higher, which will reduce the LEDs' brightness.
The LEDs have a nominal forward voltage of 1.4 V and the positive side of the LEDs are
driven at 3.3V, so you can raise the GND voltage from 0 V up to the difference between
the two, 1.9 V, to adjust the brightness. Experimentation is encouraged!
Specifications
Symbol
Description
Minimum
Typical
Maximum
Units
VIN
*
Supply Voltage at DC Input Jack
4.8
6
8.4
V
IOUT_3.3V
Total available current output from all
headers marked as 3.3V
250
mA
IOUT_5V
Total available current output from all
headers marked as 5V
250
mA
VOUT_SERVO
Output voltage at servo headers
VIN - 0.3
V
* DO NOT exceed the maximum voltage rating of your servo motors!
Copyright © Parallax Inc.
SumoBot WX Board (#32132)
v1.1 8/17/2020 Page 7 of 9