Embedded

Bolinho uses a microcontroller esp32-s3 for controlling the hardware.

For more info check the Granulado repository.

Serial communication

The microcontroller communicates via serial to the host, and is responsible for reading the load cell and controlling the stepper motor.

This communication is done via interrogation, so that the host prompts the peripheral for data and it complies.

Protocol:

These are the available commands for the communication between the host and the peripheral.

A instruction is divided in three parts:

command data \n

• command is a 1 byte character.
• data is the payload as a string it can be also empty.
• \n is the line terminator to identify the end of an instruction.

Bolinho -> Granulado

• p -> Ping

• m[str] -> Moves stepper motor x millimeters.

  str is an int in string format.

• s -> Stop

• t -> Move to top

• g -> Get motor position millimeters.

• r -> Get instantaneous reading.

• @ -> Tare load cell

• w -> Calibrate known weight

• x[str] -> Set known weight

  str is an int with the weight in grams in string format.

• y[str] -> Set z-axis length

  str is an int with the length of the z-axis in millimeters in string format.

• j -> Get z-axis length

• d -> Get delta load

• l[str] -> Set max load

  str is an int with the maximum experiment load in grams in string format.

• v[str] -> Set max travel

  str is an int with the maximum experiment travel in mm in string format.

• a[str] -> Set max delta load

  str is an int with the maximum experiment delta load in grams / second in string format.

• e[str] -> Set motor speed

  str is an int with the maximum experiment travel in RPM in string format.

• - -> Nothing

Granulado -> Bolinho

• p -> Ping Response

• e[str] -> Erro.

  str is an string with the description of the error.

• r[str] -> Returns current reading

  str is an int in grams in string format.

• g[str] -> Returns current position in millimeters

  str is an int in string format.

• j[str] -> Returns z-axis length

  str is an int in string format.

• b -> Bottom interrupt was triggered

• t -> Top interrupt was triggered

• d[str] -> Returns delta load

  str is an int in string format.

• s -> Response to the stop command

• i[str] -> Debug info

  str is any string to be shown on the terminal.