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I. Preface
This is a gimbal infrared remote control, and the control scheme of the gimbal is completed through infrared light also has certain advantages, such as no need to lay network cables. Only a centralized IR transmitter module is required. Now make a copy of its sending encoding. The relevant parameters of the signal replication of the infrared remote control are recorded below. for future design references.
2. Signal parameters
First, the signal from the infrared remote control is directed to the breadboard through the wire. Use an oscilloscope to directly observe the signal waveform. You can see that the signal is a modulated waveform. However, this modulation pulse signal does not drop to 0V. This is presumably caused by the voltage induced by the LED. To do this, a 4.7k ohm resistor is connected in parallel to the infrared LED output signal port to re-measure the output signal. Due to the increased load resistance, it can be seen that the output signal can be reduced to 0V, and the amplitude of the signal is approximately 1.7V. This amplitude is less than the high level threshold for an ordinary 3.3V microcontroller. Later, when using a single-chip microcomputer to read the signal, it is necessary to add a DC voltage of about 0.5V to it.
▲ Figure 1.2.1 Direct measurement of LED waveform
▲ Figure 1.2.2 Signal waveform after adding 4.7k ohms
The parameters of the pulse signal are measured below, a pulse is captured with a single trigger, and the oscilloscope cursor is used to measure the replication of the pulse to 1.75V at a frequency of 37.87kHz.
● Infrared LED pulse parameters:
Amplitude: 1.75V
频率：37.87kHz
3. Coding parameters
Modify the single-chip microcomputer software, it can convert the received infrared coding time into data output through the serial port, which can be used for other single-chip microcomputer infrared control program applications. At the same time, it will modulate the code and then connect an infrared light-emitting tube output through the port to test whether the coding is correct. The encoding of the output forms a fixed C array format. It can be copied directly to a microcontroller program. At this point, the PTZ infrared control code has been extracted.
※Summary※
This article records the process of extracting the encoding of the gimbal IR remote control. The parameters of the infrared LED signal were observed, all the remote control signal codes were extracted from the AT32F421 microcontroller circuit board made a few days ago, and the tests were carried out. These signal codes are stored in the CSDN blog post, and based on these codes, the next step is to design the network PTZ infrared remote control.
Resources
[1]
HDMI Multi-Switching IR Controller: https://zhuoqing.blog.csdn.net/article/details/138367483
[2]
Zigbee Network Multiplex HDMI Switcher: https://zhuoqing.blog.csdn.net/article/details/138376275
[3]
Four Camera Motion IR LED Transmitter: https://zhuoqing.blog.csdn.net/article/details/138198827