This paragraph in conjunction with remote data transmission + + ground stations triple multifunctional handheld terminals (referred to HGS_3IN1) open source products is unknown Creative Technology Ltd. in Wuhan, following previous open source: open source flight control, open source QT ground station, the open-source machine vision after Another brand-new masterpiece aims to provide a complete one-stop drone learning program for the majority of drone learners, paving the way for Mengxin to become a drone "full stack engineer" .
1. Introduction to the communication module
HGS_3IN1 uses a high-power, high-sensitivity 2.4G wireless module based on NRF24L01+PA+LNA, and adds high-power RFX2401C power amplifier chip and LNA chip, radio frequency switch and band-pass filter so that the module can achieve long-distance transmission and the maximum air transmission rate 2Mbps, multi-frequency points can satisfy multi-point communication and FM communication.
The receiver + data transmission terminal adopts the integrated wireless radio frequency module ML01SP4, which adopts the original imported chip nRF24L01+PA, which is made of high-precision resistors, capacitors, and inductance patches, with a metal shield to ensure extreme complexity in the air end of the drone Stable data transmission under electrical conditions.
2. Introduction of remote control hardware resources and interfaces
The remote control adopts the 32-bit microprocessor STM32F103RBT6 of the main control chip mainstream enhanced ARM Cortex-M3 MCU, the main frequency is 72MHz, the chip has 128 KB Flash and 20 KB SRAM, two 12-bit ADCs, three general-purpose 16-bit timers and one PWM timer is equipped with standard and advanced communication interfaces: two I2C and SPI, up to 5 serial ports, one USB and one CAN, etc. At the same time, the remote control is equipped with 2K external EEPROM for storing setting data and realizing user operation memory function.
The remote control comes with a 5V/1A power management chip, which can be directly inserted into the MICRO USB port to charge the remote control battery. It is equipped with a large-capacity lithium battery of 880mAh, which can achieve up to 600 minutes of long-lasting work when fully charged.
Equipped with a 128*84 resolution OLED display screen, with the remote control open source GUI system, it can realize friendly human-machine interaction.
Equipped with 0955 pocket version buzzer used to cooperate with the button to realize the alarm function of single click, long press and save under special conditions.
Equipped with roll, pitch, throttle, and yaw direction stick potentiometers. In addition, there are four-way two-gear button switches SWA, SWD, SWC, SWD, and two left and right dial potentiometers for analog output. VRA, VRB.
For beginners flying in a model airplane simulator, the remote controller is equipped with an AUDIO 3.5mm audio earphone port, which is used to connect computer audio or a dongle to realize the simulated flight operation on the PC side.
The remote USB virtual serial port and URT1 serial port can be used to transparently transmit data from the data transmission terminal to the ground station. With the anonymous innovative open source ground station, it can realize functions such as status display, data waveform, parameter debugging, flight control calibration, and basic serial port transceiver.
Serial port 3 is used to connect to the GPS module. The remote controller can send GPS data parsed by itself to the flight control terminal to realize the functions of drone flight and dynamic tracking of ground-side objects. Serial port 4 is a spare serial port, and the LINK interface is used for SWD download and debug interface.
There are 8 independent buttons on the board for turning the display screen, changing parameters, maintaining parameters, restoring defaults, etc. The function of each button is listed below.
| button | dog | Press |
|---|---|---|
| K1 | no | no |
| K2 | Single self-addition of parameters | Continuously add parameters |
| K3 | no | Send GPS data |
| K4 | Parameter once | Parameter continuous decrement |
| K5 | Page up | Restore default parameters |
| K6 | Cut one line | no |
| K7 | Page down | Save current parameters |
| K8 | Cut up and down | no |
3. Routine operation and setting of remote control
3.1 Code matching between the remote control and the receiver
When the receiver enters the code matching state, you need to press the receiver code button while the receiver is powered on, and the receiver indicator will enter a fast flashing state.
When the remote control enters the code matching state, the operation is as follows. When the remote control is off, keep pressing the K7 button, and then turn on the remote control switch, the remote control will enter the code matching state, and the RGB status indicator red light will enter the flashing state. After the code is successfully coded, the buzzer chairman will enter the normal working interface with a beep.
After the remote control enters the code matching state, it will send the unique remote control channel + communication address generated by the chip ID to the receiver that is currently in the code matching state. After the remote control successfully parses to the successful sending flag bit, the code will be automatically checked successfully. . After the receiver receives the remote control channel and communication address, it will save the data in the internal FLASH. When the receiver is normally powered on, it will read the channel and address data and configure NRF to realize pairing with the remote control.
3.2 Homepage key data display
The remote control homepage mainly displays key data such as communication connection quality, GPS satellite positioning, unlock status, battery power, flight altitude/radius, climb/cruise speed, attitude angle, temperature control system temperature, etc. The interface is as follows.
3.3 Setting of communication channel and address
The default communication channel and address of the remote control are generated based on the unique ID of the chip. When there are multiple devices in the same environment in the same or similar devices, there may be interference in the data. Therefore, when the remote control and the receiver are found to be unobstructed at close range When the analog RSSI of the communication signal is not 100%, you can manually adjust the communication channel or communication address. The setting interface is as follows:
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3.4 Failsafe setting
The remote control runaway protection is used to force a channel of the remote control to output a preset runaway value when the communication between the remote control and the receiver is completely lost or the communication RSSI is less than 15%. The flight control program can judge the data of this channel and make automatic Operations such as returning home and landing on the spot. The usual practice is to correspond the channel number and channel value to the flight control one-key return channel, or it can be judged separately.
3.5 Low pressure alarm
The low voltage alarm is used to set the safe power of the remote control and the safe power of the aircraft, and judge the current voltage value in real time. When the voltage is lower than the set safe value, the buzzer of the remote control will sound to remind the operator to perform the return and landing operations in time .
3.6 Mode channel settings
Function mode channel mapping setting is used to set the sequence of 5, 6, 7, 8, 9, and 10 channels output by the remote control. Each channel can be selected with switch positions SWA, SWB, SWC, SWD and analog channel VRA , VRB, users can map by themselves according to the actual aircraft mode.
3.7 Direction channel stroke and offset setting
The stroke and offset can be set for the first four channels of the remote control. The offset can be set to [-100,100], the minimum stroke setting range is [900,1500], and the minimum stroke setting range is [1500,2100] ], when the range to be adjusted is relatively large, you can long press the plus and minus button, the longer the time, the greater the acceleration and deceleration.
It should be noted that all the above setting operations need to be saved for a long time, that is, when the last setting is still saved after power off and restart, you need to long press K7 to save after setting, otherwise it will only be valid for the current time. When you need to restore the default parameters, long press the K5 button to restore the factory default parameters.
3.8 Other data pages
The user data channel display, IMU data display, GPS positioning radar display, onboard GPS data display and other interfaces are as follows:
4. The use of receiver and data transmission
When used as a receiver only, you only need to solder the delivered connecting wire to the pad on the back of the module. The black wire is connected to GND (labeled GD), the red wire is connected to 5V, and the white wire is selected according to the signal type supported by the actual flight controller. Marked PM) or SBUS (marked SB) solder joints, the final completed picture is as follows:
At the same time, the receiving module also supports the transparent transmission function of the serial port. Since the maximum data volume of NRF24L01 single transmission is 32 bytes, when used as a transparent transmission function, the single frame data should not exceed 32, otherwise the data communication will be blocked and affect the final communication quality . When the transparent serial port of the receiver is connected to the Wuming Innovation series flight control products, Wuming Innovation TI's full series of open source flight control products are as follows:
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The remote control terminal can output corresponding transparent transmission data through the USB virtual serial port and serial port 1, and the wireless serial port data transmission function can be realized when connected to an anonymous ground station.
Appendix to this article:
Remote control open source information github link:
https://github.com/wustyuyi/HGS_HP
https://download.csdn.net/download/u011992534/12868948
Remote control function demonstration tutorial:
https://www.bilibili.com/video/BV1Gz4y1Q7gn
Anonymous innovative open source ground station tutorial:
https://blog.csdn.net/u011992534/article/details/105341638/
Anonymous innovative dream chaser H7 high-end open source flight control learning platform DreamerPilot (master control STM32H743VIT6)
https://www.bilibili.com/video/BV19T4y1L7j9#reply3509591146
https://www.bilibili.com/video/BV1Pi4y1u7Rd
Dreamcatcher H7 high-end open source flight control dual IMU redundancy
Accelerometer/gyro: BMI088, ICM20689
Magnetometer: IST8310, AK8975 Barometer: SPL06, FBM320
Main core algorithm attitude calculation + integrated navigation: extended Kalman filter (EKF)
Control algorithm: ADRC+PID
Sensor filtering: 8KHz sampling + high-order digital filtering (low pass, band rejection)
Sensor fault diagnosis: dynamic real-time monitoring of root mean square error, variance, etc., and select the optimal fusion scheme
Support a variety of ground stations: unnamed ground station + MP/QGC support indoor and outdoor optical flow/GPS fixed point, radar terrain tracking, fixed speed cruise, waypoint flight, SDK command control mode