Adding coarse plates to a manipulator increases the friction between the manipulator and the object it is holding. Why didn't I think about it right away?

The bug was in the button checking code and was causing the debounce filter to work every cycle of infinite loop.

bool button_pressed(button_t *btn)
{
    bool pressed = FALSE;
    BitStatus current_status = !!GPIO_ReadInputPin(btn->gport, btn->gpin);

    if (btn->_last_status != current_status) {
        delay_ms(5);
        current_status = GPIO_ReadInputPin(btn->gport, btn->gpin);
    }
    ...

There is a typo here that gets compiled and causes an increase in the response time of the remote by 30 ms (6 buttons, 5 ms for debouncing). The GPIO_ReadInputPin() function returns not a bool value, but a bitmask, i.e. 0 if logic level on the pin is low and (1 << pin) if the logic level on the pin is high.

So the right code looks like that:

bool button_pressed(button_t *btn)
{
    bool pressed = FALSE;
    BitStatus current_status = !!GPIO_ReadInputPin(btn->gport, btn->gpin);

    if (btn->_last_status != current_status) {
        delay_ms(5);
        // Forgot to normalize to 0..1
        current_status = !!GPIO_ReadInputPin(btn->gport, btn->gpin);
    }
    ...

Photos

FPV photos:

FPV Videos:

A huge update for robot and RC is just released. I was working on it since summer (but not only on it of course).

Hardware update:

An extension board added. The board provides an easy way to connect different modules to power lines with different voltage and data interface lines (SPI, I2C, 1-Wire) without soldering.

FPV Camera has been moved to a place with a better view. So, the robot has become a little more compact.

Powerful lighting LED instead of 4 green LEDs which actually don't provide enough light to make the camera see anything in the darkness.

Small constructive improvements to the remote control case. No impressing photos.

---

Software update:

of robot: https://github.com/Danya0x07/DUMRON/releases/tag/v2.0 (in Russian)

• Refactoring names and CodeStyle, how can we do without it!)
• Moving the code for interaction with NRF24L01 + and DS18B20 into separate, cross-platform super-duper libraries with documentation, examples and other benefits of humanity;
  
• The DS18B20 library implements checksum verification, so the heresy about temperature no longer comes to the RC.
• Added power-on self test;
• Added debug logs to UART and runtime errors indication;
• Detected and fixed a stack overflow in one of the tasks;
  
• Various local optimizations (eg. uint8_t -> uint_fast8_t);
  
• Battery charge measurement now works not "head-on", but through DMA;
  
• Optimized manipulator control, now, when it does not move, its software timer does not spin idle, but stopped;
  
• The communication protocol with the RC has been rethought and optimized, the encapsulation of data from the rear rangefinder has been improved.
  
• Added detection of mechanical failure of the rear rangefinder;
  
• Migration to CMSIS-RTOS APIv2;
  
• Added the ability to change the radio frequency channel by command from the RC.
  

of remote control: https://github.com/Danya0x07/DUMRON_RC/releases/tag/v2.0 (in Russian)

• Migration to the PlatformIO build system;
• Moving the Nokia display Interaction code into a standalone PCD8544 cross-platform library;
• Added energy saving measures (redundant microcontroller subsystems are disabled);
• Added scanning of the radio frequency range after power on and switching the RC and the robot to the new selected clear channel;
• GUI updated and improved;
• Refactoring and optimization of various kinds;