Add Laser Based I2C Ammeter Feature (#21835)

Marlin/Configuration_adv.h

     //#define AIR_ASSIST_PIN            44     // Override the default Air Assist pin
   #endif
 
+  //
+  // Laser I2C Ammeter (High precision INA226 low/high side module)
+  //
+  //#define I2C_AMMETER
+  #if ENABLED(I2C_AMMETER)
+    #define I2C_AMMETER_IMAX            .1     // Calibration value for the expected current range in Amps (use float e.g. 1.0)
+    #define I2C_AMMETER_SHUNT_RESISTOR  .1     // Calibration shunt resistor value in ohms
+  #endif
+
   //#define SPINDLE_SERVO                      // A servo converting an angle to spindle power
   #ifdef SPINDLE_SERVO
     #define SPINDLE_SERVO_NR   0               // Index of servo used for spindle control

Marlin/src/feature/ammeter.cpp

+  /**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "../inc/MarlinConfig.h"
+
+#if ENABLED(I2C_AMMETER)
+  #include "ammeter.h"
+
+  INA226 ina;
+
+  Ammeter ammeter;
+
+  float Ammeter::scale;
+  float Ammeter::current;
+
+  void Ammeter::init() {
+    ina.begin();
+    ina.configure(INA226_AVERAGES_16, INA226_BUS_CONV_TIME_1100US, INA226_SHUNT_CONV_TIME_1100US, INA226_MODE_SHUNT_BUS_CONT);
+    ina.calibrate(I2C_AMMETER_SHUNT_RESISTOR,I2C_AMMETER_IMAX);
+  }
+
+  float Ammeter::read() {
+      scale = 1;
+      current = ina.readShuntCurrent();
+      if (current <= .0001) current = 0;  // Cleanup lsb bit amplification errors
+      if (current < .1) scale = 1000; 
+      return current * scale;
+  }
+
+#endif //I2C_AMMETER

Marlin/src/feature/ammeter.h

+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+#include "../inc/MarlinConfigPre.h"
+
+#include <Wire.h>
+#include <INA226.h>
+
+#ifndef I2C_AMMETER_IMAX    
+  #define I2C_AMMETER_IMAX      .500 // Calibration range 500 Milli Amps
+#endif
+
+class Ammeter {
+private:
+    static float scale;
+
+public:
+    static float current;
+    static void init();
+    static float read();
+ 
+};
+
+extern Ammeter ammeter;

Marlin/src/feature/spindle_laser.cpp

   #include "../module/servo.h"
 #endif
 
+#if ENABLED(I2C_AMMETER)
+  #include "../feature/ammeter.h"
+#endif
+
 SpindleLaser cutter;
 uint8_t SpindleLaser::power;
 #if ENABLED(LASER_FEATURE)
   #if ENABLED(AIR_ASSIST)
     OUT_WRITE(AIR_ASSIST_PIN, !AIR_ASSIST_ACTIVE);                    // Init Air Assist OFF
   #endif
+  #if ENABLED(I2C_AMMETER)
+    ammeter.init();                    // Init I2C Ammeter
+  #endif
+  
 }
 
 #if ENABLED(SPINDLE_LASER_PWM)

Marlin/src/lcd/HD44780/marlinui_HD44780.cpp

   #include "../../feature/cooler.h"
 #endif
 
+#if ENABLED(I2C_AMMETER)
+  #include "../../feature/ammeter.h"
+#endif
+
 #if ENABLED(AUTO_BED_LEVELING_UBL)
   #include "../../feature/bedlevel/bedlevel.h"
 #endif
 
 #if ENABLED(LASER_COOLANT_FLOW_METER)
   FORCE_INLINE void _draw_flowmeter_status() {
-    lcd_put_u8str("~ ");
+    lcd_put_u8str("~");
     lcd_put_u8str(ftostr11ns(cooler.flowrate));
     lcd_put_wchar('L');
   }
 #endif
 
+#if ENABLED(I2C_AMMETER)
+  FORCE_INLINE void _draw_ammeter_status() {
+    lcd_put_u8str(" ");
+    ammeter.read();
+    if (ammeter.current <= .999) {
+      lcd_put_u8str(ftostr3ns(ammeter.current));
+      lcd_put_u8str("mA");
+    } else {
+      lcd_put_u8str(ftostr12ns(ammeter.current));
+      lcd_put_wchar('A');
+    }
+  }
+#endif
+
 FORCE_INLINE void _draw_bed_status(const bool blink) {
   _draw_heater_status(H_BED, TERN0(HAS_LEVELING, blink && planner.leveling_active) ? '_' : LCD_STR_BEDTEMP[0], blink);
 }
       #if ENABLED(LASER_COOLANT_FLOW_METER)
         _draw_flowmeter_status();
       #endif
+      #if ENABLED(I2C_AMMETER)
+        _draw_ammeter_status();
+      #endif
 
     #endif // LCD_WIDTH >= 20
 

Marlin/src/lcd/dogm/dogm_Statusscreen.h

   #define STATUS_FLOWMETER_BYTEWIDTH BW(STATUS_FLOWMETER_WIDTH)
 #endif
 
-
+//
+// Laser Ammeter
+//
+#if !STATUS_AMMETER_WIDTH && ENABLED(I2C_AMMETER)
+  #include "status/ammeter.h"
+#endif
+#ifndef STATUS_AMMETER_WIDTH
+  #define STATUS_AMMETER_WIDTH 0
+#endif
+#ifndef STATUS_AMMETER_BYTEWIDTH
+  #define STATUS_AMMETER_BYTEWIDTH BW(STATUS_AMMETER_WIDTH)
+#endif
 
 //
 // Bed
   #endif
 #endif
 
+#if ENABLED(I2C_AMMETER)
+  #if STATUS_AMMETER_WIDTH
+
+    #ifndef STATUS_AMMETER_X
+      #define STATUS_AMMETER_X (LCD_PIXEL_WIDTH - (STATUS_AMMETER_BYTEWIDTH + STATUS_FLOWMETER_BYTEWIDTH + STATUS_FAN_BYTEWIDTH + STATUS_CUTTER_BYTEWIDTH + STATUS_COOLER_BYTEWIDTH) * 8)
+    #endif
+
+    #ifndef STATUS_AMMETER_HEIGHT
+      #define STATUS_AMMETER_HEIGHT(S) (sizeof(status_ammeter_bmp1) / (STATUS_AMMETER_BYTEWIDTH))
+    #endif
+
+    #ifndef STATUS_AMMETER_Y
+      #define STATUS_AMMETER_Y(S) (18 - STATUS_AMMETER_HEIGHT(S))
+    #endif
+
+    #ifndef STATUS_AMMETER_TEXT_X
+      #define STATUS_AMMETER_TEXT_X (STATUS_AMMETER_X + 7)
+    #endif
+
+    static_assert(
+      sizeof(status_ammeter_bmp1) == (STATUS_AMMETER_BYTEWIDTH) * STATUS_AMMETER_HEIGHT(0),
+      "Status ammeter bitmap (status_ammeter_bmp1) dimensions don't match data."
+    );
+  #endif
+#endif
+
 //
 // Bed Bitmap Properties
 //
 #if ENABLED(LASER_COOLANT_FLOW_METER)
   #define DO_DRAW_FLOWMETER 1
 #endif
+#if ENABLED(I2C_AMMETER)
+  #define DO_DRAW_AMMETER 1
+#endif
 
 #if HAS_TEMP_CHAMBER && STATUS_CHAMBER_WIDTH && HOTENDS <= 4
   #define DO_DRAW_CHAMBER 1

Marlin/src/lcd/dogm/status/ammeter.h

+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2020 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#pragma once
+
+//
+// lcd/dogm/status/ammeter.h - Status Screen Laser Ammeter bitmaps
+//
+#if ENABLED(I2C_AMMETER)
+
+  #define STATUS_AMMETER_WIDTH 20
+
+  const unsigned char status_ammeter_bmp_mA[] PROGMEM = {
+  B00000000,B11111100,B00000000,
+  B00000011,B00000011,B00000000,
+  B00000100,B00000000,B10000000,
+  B00001000,B00000000,B01000000,
+  B00010000,B00000110,B00100000,
+  B00010000,B00001001,B00100000,
+  B00100000,B00001001,B00010000,
+  B00100011,B01001111,B00010000,
+  B11100010,B10101001,B00011100,
+  B00100010,B10101001,B00010000,
+  B00100010,B10101001,B00010000,
+  B00010000,B00000000,B00100000,
+  B00010000,B00000000,B00100000,
+  B00001000,B00000000,B01000000,
+  B00000100,B00000000,B10000000,
+  B00000011,B00000011,B00000000,
+  B00000000,B11111100,B00000000
+  };
+
+const unsigned char status_ammeter_bmp_A[] PROGMEM = {
+  B00000000,B11111100,B00000000,
+  B00000011,B00000011,B00000000,
+  B00000100,B00000000,B10000000,
+  B00001000,B00000000,B01000000,
+  B00010000,B00000000,B00100000,
+  B00010000,B00110000,B00100000,
+  B00100000,B01001000,B00010000,
+  B00100000,B01001000,B00010000,
+  B11100000,B01111000,B00011100,
+  B00100000,B01001000,B00010000,
+  B00100000,B01001000,B00010000,
+  B00010000,B01001000,B00100000,
+  B00010000,B00000000,B00100000,
+  B00001000,B00000000,B01000000,
+  B00000100,B00000000,B10000000,
+  B00000011,B00000011,B00000000,
+  B00000000,B11111100,B00000000,
+};
+
+#endif

Marlin/src/lcd/dogm/status/cooler.h

   #define STATUS_COOLER_WIDTH 22
 
   const unsigned char status_cooler_bmp2[] PROGMEM = {
-    B00000100,B00000010,B00000000,
-    B00000100,B10010010,B01000000,
-    B00010101,B00001010,B10000000,
-    B00001110,B00000111,B00000000,
-    B00111111,B10111111,B11000000,
-    B00001110,B00000111,B00000000,
-    B00010101,B00001010,B10000000,
-    B00100100,B00100010,B01000000,
-    B00000100,B00100000,B00000000,
-    B00000001,B00100100,B00000000,
-    B00000000,B10101000,B00000000,
-    B00000000,B01110000,B00000000,
-    B00000111,B11111111,B00000000,
-    B00000000,B01110000,B00000000,
-    B00000000,B10101000,B00000000,
-    B00000001,B00100100,B00000000
+    B00000001,B00000000,B10000000,
+    B00000001,B00100100,B10010000,
+    B00000101,B01000010,B10100000,
+    B00000011,B10000001,B11000000,
+    B00001111,B11101111,B11110000,
+    B00000011,B10000001,B11000000,
+    B00000101,B01000010,B10100000,
+    B00001001,B00001000,B10010000,
+    B00000001,B00001000,B00000000,
+    B00000000,B01001001,B00000000,
+    B00000000,B00101010,B00000000,
+    B00000000,B00011100,B00000000,
+    B00000001,B11111111,B11000000,
+    B00000000,B00011100,B00000000,
+    B00000000,B00101010,B00000000,
+    B00000000,B01001001,B00000000
   };
   const unsigned char status_cooler_bmp1[] PROGMEM = {
-    B00000100,B00000010,B00000000,
-    B00000100,B10010010,B01000000,
-    B00010101,B00001010,B10000000,
-    B00001010,B00000101,B00000000,
-    B00110001,B11011000,B11000000,
-    B00001010,B00000101,B00000000,
-    B00010101,B00001010,B10000000,
-    B00100100,B00100010,B01000000,
-    B00000100,B00100000,B00000000,
-    B00000001,B00100100,B00000000,
-    B00000000,B10101000,B00000000,
-    B00000000,B01010000,B00000000,
-    B00000111,B10001111,B00000000,
-    B00000000,B01010000,B00000000,
-    B00000000,B10101000,B00000000,
-    B00000001,B00100100,B00000000
+    B00000001,B00000000,B10000000,
+    B00000001,B00100100,B10010000,
+    B00000101,B01000010,B10100000,
+    B00000010,B10000001,B01000000,
+    B00001100,B01110110,B00110000,
+    B00000010,B10000001,B01000000,
+    B00000101,B01000010,B10100000,
+    B00001001,B00001000,B10010000,
+    B00000001,B00001000,B00000000,
+    B00000000,B01001001,B00000000,
+    B00000000,B00101010,B00000000,
+    B00000000,B00010100,B00000000,
+    B00000001,B11100011,B11000000,
+    B00000000,B00010100,B00000000,
+    B00000000,B00101010,B00000000,
+    B00000000,B01001001,B00000000
   };
 
 #endif

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

   }
 #endif
 
+#if DO_DRAW_AMMETER
+  FORCE_INLINE void _draw_centered_current(const float current, const uint8_t tx, const uint8_t ty) {
+    const char *str = ftostr31ns(current);           
+    const uint8_t len = str[0] != ' ' ? 3 : str[1] != ' ' ? 2 : 1;
+    lcd_put_u8str(tx - len * (INFO_FONT_WIDTH) / 2 + 1, ty, &str[3-len]);
+  }
+#endif
+
 #if DO_DRAW_HOTENDS
 
   // Draw hotend bitmap with current and target temperatures
   }
 #endif
 
+#if DO_DRAW_AMMETER
+  FORCE_INLINE void _draw_ammeter_status() {
+    if (PAGE_CONTAINS(28 - INFO_FONT_ASCENT, 28 - 1))
+      _draw_centered_current(ammeter.read(), STATUS_AMMETER_TEXT_X, 28);
+  }
+#endif
+
 //
 // Before homing, blink '123' <-> '???'.
 // Homed but unknown... '123' <-> '   '.
         u8g.drawBitmapP(STATUS_FLOWMETER_X, flowmetery, STATUS_FLOWMETER_BYTEWIDTH, flowmeterh, blink && cooler.flowpulses ? status_flowmeter_bmp2 : status_flowmeter_bmp1);
     #endif
 
+    // Laser Ammeter
+    #if DO_DRAW_AMMETER
+      const uint8_t ammetery = STATUS_AMMETER_Y(status_ammeter_bmp_mA),
+                    ammeterh = STATUS_AMMETER_HEIGHT(status_ammeter_bmp_mA);
+       if (PAGE_CONTAINS(ammetery, ammetery + ammeterh - 1))
+        u8g.drawBitmapP(STATUS_AMMETER_X, ammetery, STATUS_AMMETER_BYTEWIDTH, ammeterh, (ammeter.current < .1) ? status_ammeter_bmp_mA : status_ammeter_bmp_A);
+    #endif
 
     // Heated Bed
     TERN_(DO_DRAW_BED, _draw_bed_status(blink));
     // Flowmeter
     TERN_(DO_DRAW_FLOWMETER, _draw_flowmeter_status());
 
+    // Flowmeter
+    TERN_(DO_DRAW_AMMETER, _draw_ammeter_status());
+
     // Fan, if a bitmap was provided
     #if DO_DRAW_FAN
       if (PAGE_CONTAINS(STATUS_FAN_TEXT_Y - INFO_FONT_ASCENT, STATUS_FAN_TEXT_Y - 1)) {

Marlin/src/libs/numtostr.cpp

   return &conv[2];
 }
 
+// Convert unsigned float to string with 123 format
+const char* ftostr3ns(const_float_t f) {
+  const long i = UINTFLOAT(f, 3);
+  conv[4] = DIGIMOD(i, 100);
+  conv[5] = DIGIMOD(i, 10);
+  conv[6] = DIGIMOD(i, 1);
+  return &conv[4];
+}
+
 // Convert signed float to fixed-length string with 12.34 / _2.34 / -2.34 or -23.45 / 123.45 format
 const char* ftostr42_52(const_float_t f) {
   if (f <= -10 || f >= 100) return ftostr52(f); // -23.45 / 123.45

Marlin/src/libs/numtostr.h

 // Convert unsigned float to string with 123.4 format
 const char* ftostr41ns(const_float_t x);
 
+// Convert unsigned float to string with 123 format
+const char* ftostr3ns(const_float_t x);
+
 // Convert signed float to fixed-length string with 12.34 / _2.34 / -2.34 or -23.45 / 123.45 format
 const char* ftostr42_52(const_float_t x);
 

ini/features.ini

 NEOPIXEL_LED                           = adafruit/Adafruit NeoPixel@~1.8.0
                                          src_filter=+<src/feature/leds/neopixel.cpp>
 TEMP_.+_IS_MAX31865                    = Adafruit MAX31865 library@~1.1.0
+I2C_AMMETER                            = peterus/INA226Lib@1.1.2
 USES_LIQUIDCRYSTAL                     = fmalpartida/LiquidCrystal@1.5.0
 USES_LIQUIDCRYSTAL_I2C                 = marcoschwartz/LiquidCrystal_I2C@1.1.4
 USES_LIQUIDTWI2                        = LiquidTWI2@1.2.7