RoboRally/docs/2_ROBOT_SETUP.md

Robot setup

This file explains how to setup the software for the robots. It assumes that you already assembled your robot according to the instructions in 1_ASSEMBLY.md

1 Install esptool

The chip on the Wemos D1 mini is a Esp8266. In order to flash programs on this chip we will use esptool by Espressif. You can install it using pip:

$ pip install esptool

2 Update Motor shield firmware

The Wemos motor shield comes with a buggy firmware which has problems with the I2C communication ([see here](buggy firmware)). Luckily, some guys figured out how to update the firmware of the STM32 on the motor shield with a custom one that fixes these issues.

These are the necessary steps:

Install arm compiler:

$ sudo add-apt-repository ppa:team-gcc-arm-embedded/ppa
$ sudo apt-get update
$ sudo apt-get install gcc-arm-embedded

Build the firmware:

Get the firmware from: https://github.com/pbugalski/wemos_motor_shield

$ make

-> motor_shield.bin

Upload empty firmware to Wemos D1 mini

We will program the STM32 on the motor shield using the serial USB connection from the Wemos D1 mini. The D1 mini should just pass through the serial communication to the STM32. For this we need to upload a dummy firmware to the D1 mini.

1. Make sure the RTS and 3V port of the Wemos motor shield are connected by a wire (you should already have done this in the assembly instructions). Also make sure that the I2C bridge connection on the motor shield is set.

2. Plug the Wemos D1 mini on top of the motor shield and then connect it to your PC using a micro USB cable

3. Compile the sketch below into a .bin file using the Arduino IDE -> dummy_sketch.ino.d1_mini.bin or use the one from bin/dummy_sketch.ino.d1_min.bin

Note: If you you compile it yourself make sure you choose the Wemos D1 mini board as target for the build.

void setup() {
  // just some dummy code
}

void loop() {
  // just some dummy code
}

4. Erase flash on the chip:

$ esptool.py --port /dev/ttyUSB0 erase_flash

5. Flash the dummy sketch:

$ esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 dummy_sketch.ino.d1_mini.bin/dummy_sketch.ino.d1_mini.bin.ino.d1_mini.bin

Install stm32flash utility:

To upload a new firmware to the STM32 that is running on the motor shield we need the STM32 flash utility. You can download from: https://sourceforge.net/projects/stm32flash/files/ You should then build and install it using the usual:

$ make
$ make install

Connect the motor shield to D1 mini:

Use some jumper cables to connect the motor shield and the D1 mini in the following way.

Wemos D1 mini	Motor shield
TX	D1
RX	D2
3V	3V
GND	GND

In addition on the motor shield connect 3V to RTS Also make sure that the I2C bridge connection on the motor shield is set.

Then, connect the D1 mini to your PC using a micro USB cable.

Flash the new firmware on the STM32:

1. Check if you can communicate with the STM32:

$ stm32flash /dev/ttyUSB0

Output should be:

Interface serial_posix: 57600 8E1
Version      : 0x31
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0444 (STM32F03xx4/6)
- RAM        : 4KiB  (2048b reserved by bootloader)
- Flash      : 32KiB (size first sector: 4x1024)
- Option RAM : 16b
- System RAM : 3KiB

2. Unlock shield:

$ stm32flash -k /dev/ttyUSB0

Output should be:

stm32flash 0.5

http://stm32flash.sourceforge.net/

Interface serial_posix: 57600 8E1
Version      : 0x31
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0444 (STM32F03xx4/6)
- RAM        : 4KiB  (2048b reserved by bootloader)
- Flash      : 32KiB (size first sector: 4x1024)
- Option RAM : 16b
- System RAM : 3KiB
Read-UnProtecting flash
Done.

3. Flash new motor driver:

$ stm32flash -f -v -w motor_shield.bin /dev/ttyUSB0

Output should be:

stm32flash 0.5

http://stm32flash.sourceforge.net/

Using Parser : Raw BINARY
Interface serial_posix: 57600 8E1
Version      : 0x31
Option 1     : 0x00
Option 2     : 0x00
Device ID    : 0x0444 (STM32F03xx4/6)
- RAM        : 4KiB  (2048b reserved by bootloader)
- Flash      : 32KiB (size first sector: 4x1024)
- Option RAM : 16b
- System RAM : 3KiB
Write to memory
Erasing memory
Wrote and verified address 0x08000be8 (100.00%) Done.

Cleaning up

Finally, you can remove the wire between RTS and 3V. At this point, please make sure that the I2C bridge on the Wemos Motor shield is connected. This is necessary for I2C to work correctly.

Flash Micropython to the Wemos D1 mini

The next step is to flash the micropython firmware to

$ esptool.py --port /dev/ttyUSB0 erase_flash
$ esptool.py --port /dev/ttyUSB0 --baud 460800 write_flash --flash_size=detect 0 esp8266-20190125-v1.10.bin

Setting up webrepl: Connect using picocom:

  $ picocom /dev/ttyUSB0 -b115200

3. Connect via picocom and enable Webrepl

>>> import webrepl_setup

-> enable, set password and reboot

Connect to local wifi:

  >>> import network
  >>> sta_if = network.WLAN(network.STA_IF)
  >>> sta_if.active(True)
  >>> sta_if.connect("<SSID>", "<PW>")
  >>> sta_if.ifconfig() # this prints the IP

Use access point to connect:

  >>> import network
  >>> ap_if = network.WLAN(network.AP_IF)
  >>> ap_if.active(True)
  >>> ap_if.ifconfig() # this prints the IP

Default password for the access point: micropythoN

Connect via online WebREPL:

• Enter IP from above and click connect. Login with password.
• Upload boot.py via Webrepl to automatically connect to wifi and start webrepl after reboot
• You can also upload a file called main.py or just work in the webrepl terminal.

4. Connect via webpage and upload boot.py, main.py, etc. Modify boot.py before uploading!

5. Connect to the robot and test the connection

The next step is to setup the position detection using ROS. For this see the ROS_SETUP.txt