matrixorbital / eve-knob

An Arduino Project. A simple AS5048 based infinitely rotating knob that you can add to any electronics project

A small quantity of joy is added to the Universe each time a knob is spun.

Using the AS5048B from AMS allows the knob to rotate freely and infinitely while reading the position via I2C. AMS makes a handy and inexpensive eval-board which is available from Mouser: 985-AS5048A-TS_EK_AB

In essence, this is a rotational encoder capable of 1/20th degree resolution (7300 counts per revolution). The technology is also useful in robotics to quantify wheel rotation or joint extension.

• Designed for Matrix Orbital EVE2 SPI TFT Displays

  https://www.matrixorbital.com/ftdi-eve

• This code makes use of the Matrix Orbital EVE2 Library found here:

  https://github.com/MatrixOrbital/EVE2-Library

  • While a copy of the library files (Eve2_81x.c and Eve2_81x.h) is included here, you may look for updated files if you wish. This is optional, but the Eve2-Library is likely to contain an extension of what you have here in case you wish to make some more advanced screens.

• Matrix Orbital EVE2 SPI TFT display information can be found at: https://www.matrixorbital.com/ftdi-eve

• An Arduino shield with a connector for Matrix Orbital EVE2 displays is used to interface the Arduino to Eve.
  This shield includes:

  • 20 contact FFC connector for Matrix Orbital EVE2 displays
  • 3 pushbuttons for application control without requiring a touchscreen (useful for initial calibration)
  • Audio amplifier and speaker for audio feedback
  • SD card holder
  • Additionally, the shield board is automatically level shifted for 5V Arduino and works with 3.3V Parallax Propeller ASC+

  Support Forums

  http://www.lcdforums.com/forums/viewforum.php?f=45

  

eve-knob's Issues

Cmd_Keys not implemented

I have not found CMD_KEYS implemented in any MatrixOrbital code. I did find it implemented in the Riverdi code and extrapolated to get it into the Matrix Orbital code (nearly identical to the Cmd_Text). However the implementation seems to be somehow flawed. It shows the keys but with the extra "stacking" issue shown below.

Given a single row of keys, each key appears to be on top of a stack of (the same shaped) keys each shifted by a few pixels vertically.
Given multiple rows of keys, just the bottom row appears as above.

Is the EVE engine in the MatrixOrbital hardware not capable of this (hence the lack of current cmd_keys) or is it this implementation?

Here is my implementation..

void Cmd_Keys(uint16_t x, uint16_t y, uint16_t w, uint16_t h, uint16_t font, uint16_t options, const char * str)
{
  
  uint16_t DataPtr, LoopCount, StrPtr;
  uint16_t length = (uint16_t)strlen(str);
  if(!length) 
    return;

  // Create a data the same size as the string only make it in 32 bit chunks instead of 8 bit.
  uint32_t* data = (uint32_t*) calloc((length/4)+1, sizeof(uint32_t));
  // With a length of three this allocates int(3/4 + 1) == 1 uint32.

  // Loop over the incoming  string and combine 4 consecutive elements into a single data element.
  StrPtr = 0;
  //for(DataPtr=0; DataPtr<(length/4); DataPtr++, StrPtr += 4)
  for(DataPtr=0; DataPtr<(length/4); DataPtr++, StrPtr += 4)
    data[DataPtr] = (uint32_t)str[StrPtr+3]<<24 | (uint32_t)str[StrPtr+2]<<16 | (uint32_t)str[StrPtr+1]<<8 | (uint32_t)str[StrPtr];
  
  // insert the remaining (less than 4) characters into the last element in data array.
  for(LoopCount=0; LoopCount<(length%4); LoopCount++, StrPtr++)
    data[DataPtr] |= (uint32_t)str[StrPtr] << (LoopCount * 8);

  //printf("-- CMD_KEYS -- Size(%d), DataPtr(%d), LoopCount(%d), Data0(%x)\n", sizeof(data[0]), DataPtr, LoopCount,  data[0]);
 
  Send_CMD(CMD_KEYS);
  Send_CMD( ((uint32_t)y << 16) | x ); // Put two 16 bit values together into one 32 bit value - do it little endian
  Send_CMD( ((uint32_t)h << 16) | w );
  Send_CMD( ((uint32_t)options << 16) | font );
  
  // Loop over the data array and send each 32 bit chunk to the display.
  for (LoopCount = 0; LoopCount <= length / 4; LoopCount++)
  {
	  Send_CMD(data[LoopCount]);
  }

  free(data);

}

No need to wait after a Wire.requestFrom().

In the file "EveKnob.ino" in the function "AS5048_GetRaw()", there is a while-statement after a Wire.requestFrom().
That while-statement can be removed, there is nothing to wait for, it is nonsense code.
Explanation: Common-mistakes#1

The while-statement is at the moment at line 413: https://github.com/MatrixOrbital/EVE-Knob/blob/master/EveKnob.ino#L413

won't compile with win10 arduino 1.8.5

First you need to rename the ino file to EVE-Knob.ino (arduino IDE complains if ino filename name doesn't match directory name)

After opening EVE-Knob.ino, compiling for uno gives this error
C:\tmp\EVE-Knob\Eve-Knob.ino:6:24: fatal error: Arduino_AL.h: No such file or directory

File Arduino_AL.h is in the same directory as ino file, but error occurs. At a loss, might be a filename case issue. Please fix.

ps. compiles fine ubuntu 16.04 arduino 1.8.9