GY-63_MS5611/libraries/M5ANGLE8

M5ANGLE8

Arduino library for M5 8ANGLE 8x12 bit potentiometers.

Description

Experimental

M5ANGLE8 is an Arduino class to read the potentiometers of the M5 8ANGLE module. It also provides means to write RGB values to the 9 LED's in the same module.

The potentiometers can be read with 8 bit (faster) or 12 bit. Derived from these two resolutions this library also supports resolutions from 1 to 12 bit. So the range can be chosen to match your application. Furthermore the library can reverse the range from 0..n => n..0.

The library has a wrapper function selectionRead(channel, steps) around the analogRead to make a selection between 0..steps-1.

The library can read the state of the mini switch.

The library can set the RGB value and brightness of the 9 LEDS.

First tests are done and the library looks stable now. Missing is an interrupt signal e.g. on change. One has to poll all channels for changes which is not efficient. A single byte register that showed change since last read would allow to monitor all 8 potentiometers in one call.

Feedback is welcome!

I2C

The address range is in theory from 0..127, however the I2C specification states it should be between 8 and 119 as some addresses are reserved. The default address is 0x43 or 67.

clock	works	notes
100 KHz	yes
200 KHz	yes
400 KHz	yes	max speed advised
600 KHz	no

See log file performance sketch.

Accuracy

The potentiometers in my test setup were quite stable and have little noise. At 12 bit resolution I got most of the time 2 bits or less noise.

The angle of 280° for 4095 values is 14~15 steps per degree, that makes it pretty difficult to set a value exactly.

The update performance of LEDs looks stable up to 40x per second in total. Beyond that frequency some blocking effects occur. Roughly determined with led_demo.

Related

• https://github.com/RobTillaart/GAMMA
• https://github.com/RobTillaart/map2colour
• https://github.com/RobTillaart/M5Angle8
• https://github.com/RobTillaart/M5ROTATE8

Interface

#include "M5ANGLE8.h"

Constructor part

• M5ANGLE8(uint8_t address = M5ANGLE8_DEFAULT_ADDRESS, TwoWire *wire = &Wire) constructor. Default address = 0x43, default Wire.
• bool begin(int sda, int scl) ESP32 et al.
• bool begin() initialize I2C, check if connected.
• bool isConnected() checks if address is on the I2C bus.
• bool setAddress(uint8_t address = M5ANGLE8_DEFAULT_ADDRESS) set a new address for the device. Default 0x43.
• uint8_t getAddress() convenience function.
• uint8_t getVersion() get firmware version from device.

Analog part

• uint16_t analogRead(uint8_t channel, uint8_t resolution = 12) Read a potentiometer, resolution can be set from 1..12 bit, constrained.
• void setReverse(bool reverse) reverse the range of the potentiometers. Default is false == 0..n (true == n..0) - think right turn.
• bool getReverse() get the current setting.
• uint16_t selectorRead(uint8_t channel, uint8_t steps) maps the analogRead upon 0..steps-1 steps.

Input switch part

• uint8_t inputSwitch() read status of the switch.

LED part

• bool writeRGB(uint8_t channel, uint8_t R, uint8_t G, uint8_t B, uint8_t brightness) Set the RGB value and brightness of a specific LED.
  channel = 0..8
  brightness - 0..100
• bool setAll(uint8_t R, uint8_t G, uint8_t B, uint8_t brightness) set all LEDS.
• bool allOff() switch all LEDs off. Returns true.

Future

Must

• improve documentation
• keep in sync with M5ROTATE8 where possible.

Should

• error handling
• bool writeBrightness(channel)
• bool readRGB(channel, &R, &G, &B, &brightness)
  • or uint32_t readRGB(uint8_t channel)
• improve on return values of functions.
• improve performance
  • faster allOff() writing 2x 16 bytes dedicated.
  • read all analog ports in one call. (array of values).
• investigate address changes

Could

• add examples
  • complex wave generator (freq, p0..p6 7 harmonics)
  • digital lock - 4096^8 possibilities in theory. 256^8 = 2^64 is enough... even 8^8 = 16 million. switch => verify trigger
  • dynamic "multi-mapping", set 8 points to match a curve.
  • equalizer 2x4 band (stereo)
  • LED colour mapping green -> yellow -> red.
• investigate pulsating LED, how much performance costs?
• investigate "optimal" polling frequency
• add unit tests

Wont (unless)

• write separate colour channels?
• caching?
  • version (not interesting),
  • RGB values = 32 bytes