/FugaraSensor

Primary LanguageEagle

FugaraSensor

General

This repository hosts the FugaraSensor project - which samples the Fluid Self's "Neurons" for touch events. Touch sensing is implemented by BMP180 based barometers. Upon a sudden change of the read barometer value, a touch event should be reflected to the host PC, via Modbus-RTU over RS485.

FugaraSensor project

This project contains the code for the touch sensing. It has a few responsibilities:

  • Periodic sampling of up to 4 barometers for air pressure reading, including calibration, stabilization disconnects, etc. Since all barometers are BMP180's with the same I2C address, we had to use Software I2C mapped to GPIO pins. The details of this are implemented in SoftI2cBmp180.*.
  • Recognition of touch event according to last N barometer samples. This should be done by looking at the past N pressure readings for each barometer independently.
  • Answer modbus RTU "read register" requests from host PC (modbus master), with the timestamp of the latest "touch" event. Each barometer corresponds to one register. Timestamps are in milliseconds since arduino's boot (enough for 46 days of consecutive operation).
  • Modbus RTU slave address is stored in the lower two bytes of the EEPROM (offset 0 - address, offset 1 - bitwise NOT of the address). This may be modified using the SlaveAddress utility (included).

FugaraSensor tweaking & customization

These files should be modified when getting ready for bringing up the project:

  • Definitions.h - pin definitions, timeouts, delays, thresholds, serial config, debug prints etc. See documentation inside that file.
  • Bmp180Pressure.cpp (bool detectTouch()) - modify the implementation of detectTouch() to handle real-world barometer pressure data. true should be returned exactly once for each touch event. If no new touch event has been recognized, should return false. Use Sample Bmp180Pressure::getSample(i) to read the sample value of the i-th recent sample (i=0 is latest, i=1 the one before it, etc).

Just incase we need to switch out the barometer for a different type of sensor, the same program layout can be used. Implement a new IPressure class, and in FugaraSensor.ino create instances of these and set pointers to them inside IPressure* pressureSensors[SENSORS_NUM].

SlaveAddress project

A small utility program to write the slave address into the device's EEPROM memory.

  1. Open the SlaveAddress sketch
  2. Modify the SLAVE_ADDR constant to the desired address (between 1-31).
  3. Compile & Upload
  4. Open Serial Monitor (baud 38400 by default)
  5. Verify the address has been written correctly (serial monitor prints).
  6. Profit.

More info