Waveshare AlphaBot User Manual page 18

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AlphaBot User Manual
Infrared control protocol:
The 32-bit binary code made up of logical "0" and logical"1" should be
secondary modulated with a 38kHz robotrier frequency, in order to enhance the
transmitting efficiency and reduce the power consumption. The secondary
modulated code will be transmitted in the form of infrared light by a infrared
transmitter, as the figure shows below.
| Boot code | User ID | Radix-minus-one complement of user ID | Op code | Radix-minus-one
complement of op code|
Firstly, a 9ms high level pulse is transmitted, and a 4.5ms low level pulse is followed.
Later coming are a 8bit address code (LSB first) and its radix-minus-one
complement (for checking). The last are a 8bit command code (LSB first) and its
radix-minus-one complement.
Each command will only be transmitted once, even you keep pressing the key on
the controller. But it will send out a duplication code every 110mS, until you release
the key on the controller. The format of the duplication code is a 9mS of AGC pulse,
a 2.25mS of interval and a 560uS of pulse.
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