0.1.2 DMM

libraries/DMM/.github/workflows/arduino-lint.yml

@@ -6,7 +6,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: arduino/arduino-lint-action@v1
         with:
           library-manager: update

libraries/DMM/.github/workflows/arduino_test_runner.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.6

libraries/DMM/.github/workflows/jsoncheck.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: json-syntax-check
         uses: limitusus/json-syntax-check@v1
         with:

libraries/DMM/CHANGELOG.md

@@ -6,14 +6,22 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.1.2] - 2023-02-03
+- add OHM measurements functions
+  - **setReferenceR(ohm), readOhm(times), readKiloOhm(times)**
+- update GitHub actions
+- update license 2023
+- refactor
+- update readme.md
+
+
 ## [0.1.1] - 2022-12-19
 - initial release...
 - renamed initial class to DMM
-- add setGain() and getGain()
-- add getNoise
+- add **setGain()** and **getGain()**
+- add **getNoise()**
 - add examples
 
-
 ## [0.1.0] - eons ago
 - initial version
 - started as a VoltMeter only class

libraries/DMM/DMM.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: DMM.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.1
+// VERSION: 0.1.2
 //    DATE: 2022-12-19
 // PURPOSE: Library for a DMM class for Arduino UNO.
 //     URL: https://github.com/RobTillaart/DMM
@@ -49,18 +49,28 @@ float DMM::getGain()
 }
 
 
+/////////////////////////////////////////////////
+//
+//  READ VOLTAGE
+//
 float DMM::readVolts(uint8_t times)
 {
   uint32_t total = 0;
-  if (times == 0) times = 1;
+  if (times == 0) 
+  {
+    times = 1;
+  }
   for (int i = 0; i < times; i++)
   {
     total += analogRead(_pin);
   }
-  float v = (total * _voltageStep) / times;
+  float volts = (total * _voltageStep) / times;
 
-  if (_gain != 1.0) v *= _gain;
-  return v;
+  if (_gain != 1.0) 
+  {
+    volts *= _gain;
+  }
+  return volts;
 }
 
 
@@ -89,6 +99,32 @@ float DMM::readNoise(uint8_t times)
 }
 
 
+/////////////////////////////////////////////////
+//
+//  READ OHM
+//
+void DMM::setReferenceR(float ohm)
+{
+  _ReferenceR = ohm;
+}
+
+
+float DMM::readOhm(uint8_t times)
+{
+  float voltage = readVolts(times);
+  
+  float R = _ReferenceR / voltage * _maxVoltage - _ReferenceR;
+  // float R = (_maxVoltage - voltage) * _ReferenceR / voltage;
+  return R;
+}
+
+
+float DMM::readKiloOhm(uint8_t times)
+{
+  return readOhm(times) * 0.001;
+}
+
+
 //  -- END OF FILE --
 
 

libraries/DMM/DMM.h

@@ -2,7 +2,7 @@
 //
 //    FILE: DMM.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.1
+// VERSION: 0.1.2
 //    DATE: 2022-12-19
 // PURPOSE: Library for a DMM class for Arduino.
 //     URL: https://github.com/RobTillaart/DMM
@@ -10,7 +10,7 @@
 
 #include "Arduino.h"
 
-#define DMM_LIB_VERSION        (F("0.1.1"))
+#define DMM_LIB_VERSION        (F("0.1.2"))
 
 
 class DMM
@@ -20,22 +20,30 @@ public:
 
   void begin(uint8_t pin, float maxVoltage, uint16_t maxSteps);
 
+
   //  CALIBRATION
   void  setMaxVoltage(float maxVoltage);
   float getMaxVoltage();
 
+
   //  GAIN e.g. due to voltage divider
   //  a 25V to 5V divider has a factor = 5.
   void  setGain(float factor = 1.0);
   float getGain();
 
-  //  READ
+
+  //  READ VOLTAGE
   float readVolts(uint8_t times = 1);
   float readMilliVolts(uint8_t times = 1);
-
   float readNoise(uint8_t times = 1);
 
 
+  //  READ OHM
+  void  setReferenceR(float ohm);
+  float readOhm(uint8_t times = 1);
+  float readKiloOhm(uint8_t times = 1); 
+
+
 private:
   uint8_t  _pin         = 14;  //  A0;
   float    _maxVoltage  = 5.0;
@@ -43,6 +51,8 @@ private:
   float    _voltageStep = _maxVoltage/_maxSteps;
 
   float    _gain        = 1.0;
+  
+  float    _ReferenceR  = 0;
 };
 
 

libraries/DMM/LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2022-2022 Rob Tillaart
+Copyright (c) 2022-2023 Rob Tillaart
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

libraries/DMM/README.md

@@ -8,7 +8,7 @@
 
 # DMM = Digital MultiMeter.
 
-Arduino library for a DMM class.
+Arduino library for a DMM (digital multimeter) class.
 
 
 ## Description
@@ -20,38 +20,86 @@ The first version only works as a voltmeter, DC only.
 It is meant to be extended in the future to be a complete Digital MultiMeter class.
 that includes amps ohms, diode testing etc.
 
-(this is an old 'toy' project, wrapped into a class)
+This is an old 'toy' project, wrapped into a class. 
+Do not expect high precision or accuracy.
 
 
-#### Related 
+#### Related
 
 - https://github.com/RobTillaart/ACS712 (current measurement).
 
 
 ## Interface
 
+```cpp
+#include "DMM.h"
+```
+
+#### Constructor
+
 - **DMM()** constructor.
 
 #### Configuration
-- **begin(uint8_t analogPin, float volts = 5.0, uint16_t maxADC = 1023)** configuration. 
+
+- **begin(uint8_t analogPin, float volts = 5.0, uint16_t maxADC = 1023)** configuration.
+Note these are the specifications of the ADC used. 
 - **void  setMaxVoltage(float maxVoltage)**
 - **float getMaxVoltage()**
 - **void  setGain(float factor = 1.0)** GAIN e.g. due to voltage divider.
-a 25V to 5V divider has a factor = 5.
+A 25V to 5V divider has a factor = 5.
 - **float getGain()** returns the set gain.
 
-#### Read
-- **float readVolts(uint8_t times = 1)** read voltage. 
+
+#### ReadVolts
+
+One must connect GND of Arduino to the GND of the device.
+```
+    [A0]---- V unknown
+   [GND]---- GND
+
+or with a divider => setGain(x)
+
+    [A0]----[divider]---- V unknown
+   [GND]----[divider]---- GND
+
+```
+
+- **float readVolts(uint8_t times = 1)** read voltage.
 Times can be set to average multiple measurements.
 - **float readMilliVolts(uint8_t times = 1)** convenience wrapper.
+- **float readNoise(uint8_t times = 1)** measure the noise on the wire.
+Assumes connected to constant voltage e.g. GND.
+
+
+#### ReadOhm
+
+The schema for measuring resistors is based on a simple voltage divider.
+See below. This schema can be extended with a selector switch that can
+switch between different reference resistors.
+
+```
+   [GND] ----[ R reference ]----[A0]----[ R unknown ]----[+5V]
+```
+
+- **void setReferenceR(uint32_t ohm = 1000)** set the reference resistor.
+units are Ohm, default = 1K.
+- **uint32_t readOhm(uint8_t times = 1)** read ohm.
+Times can be set to average multiple measurements.
+- **uint32_t readKiloOhm(uint8_t times = 1)** read ohm.
+Times can be set to average multiple measurements.
+
+Character ohm = Ω  (ALT-234 or ALT-0216 might work)
+
 
 #### Calibration
+
 - **float readNoise(uint8_t times = 1)** get noise level for accuracy.
 
+
 ## Operation
 
-Basic operation is to connect the Arduino GND to the projects GND (or -)
-and use the configured analog pin to measure (positive) voltage.
+Basic operation is to connect the Arduino GND to the projects GND (or - )
+and use the configured analog pin to measure a (positive) voltage.
 
 By adding a voltage divider one can measure larger voltages.
 The divider factor can be set with **setGain(factor)**.
@@ -63,20 +111,29 @@ To elaborate.
 ## Future
 
 #### Functional
+
 - AMPS  (how -> measure voltage over a known resistor)
-- OHM   (how -> known divider)
-- DIODE (how -> 5V or 0V)
 - CAPS  (how -> RC timing)
+  - RC (load 5 seconds)
+  - disconnect
+  - measure drop rate / time in micros.
+- DIODE (how -> 5V or 0V)
+  - DigitalRead(INPUT PULLUP) => HIGH or LOW
+  - or 0.7 volt drop from 5V
 
 
 #### Must
+
 - update documentation
 - update examples
-- add use of AREF 
+- add use of AREF
   - external or internal 1.1 Volt
+- **float setOffset(float offset)** adjust the voltage used.
+  - this is not the voltage the ADC uses internally.
 
 
 #### Should
+
 - investigate noise
 - analogReference(EXTERNAL) for external voltage for build in ADC
 - support external ADC e.g. ADS1115 for 16 bit resolution.
@@ -84,8 +141,9 @@ To elaborate.
 
 
 #### Could
+
 - multichannel compare
-- schema for 
+- schema for
 - scope functionality?
 
 

libraries/DMM/examples/DMM_ohm_demo/DMM_ohm_demo.ino

@@ -0,0 +1,48 @@
+//
+//    FILE: DMM_ohm_demo.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: demo DMM
+//     URL: https://github.com/RobTillaart/DMM
+//
+//     SCHEMA
+//
+//     [GND] ----[ R reference ]----[A0]----[ R unknown ]----[+5V]
+//
+
+#include "DMM.h"
+
+
+DMM dmm;
+
+
+void setup()
+{
+  while (!Serial);
+  Serial.begin(115200); 
+  Serial.println(__FILE__);
+  Serial.print("DMM_LIB_VERSION: ");
+  Serial.println(DMM_LIB_VERSION);
+
+  dmm.begin(A0, 5.000, 1023);  //  Arduino UNO, adjust if needed
+  dmm.setReferenceR(998);      //  R reference, adjust if needed
+}
+
+
+void loop()
+{
+  float voltage = dmm.readVolts();
+  float ohm = dmm.readOhm(3);
+  float Kohm = dmm.readKiloOhm(3);
+  Serial.print("voltage: ");
+  Serial.print(voltage);
+  Serial.print("\tohm: ");    //  Ω 
+  Serial.print(ohm);
+  Serial.print("\tKohm: ");
+  Serial.print(Kohm);
+  Serial.println();
+
+  delay(1000);
+}
+
+
+//  -- END OF FILE --

libraries/DMM/examples/Voltmeter_demo_millivolts/Voltmeter_demo_millivolts.ino

@@ -19,7 +19,7 @@ void setup()
   Serial.print("DMM_LIB_VERSION: ");
   Serial.println(DMM_LIB_VERSION);
 
-  dmm.begin(A0, 5, 1023);
+  dmm.begin(A0, 5.000, 1023);
 }
 
 
@@ -34,4 +34,4 @@ void loop()
 }
 
 
-// -- END OF FILE --
+//  -- END OF FILE --

libraries/DMM/examples/Voltmeter_demo_noise/Voltmeter_demo_noise.ino

@@ -35,4 +35,4 @@ void loop()
 }
 
 
-// -- END OF FILE --
+//  -- END OF FILE --

libraries/DMM/examples/Voltmeter_demo_volts/Voltmeter_demo_volts.ino

@@ -19,7 +19,7 @@ void setup()
   Serial.print("DMM_LIB_VERSION: ");
   Serial.println(DMM_LIB_VERSION);
 
-  dmm.begin(A0, 5, 1023);
+  dmm.begin(A0, 5.000, 1023);
 }
 
 
@@ -34,4 +34,4 @@ void loop()
 }
 
 
-// -- END OF FILE --
+//  -- END OF FILE --

libraries/DMM/examples/Voltmeter_demo_volts_gain/Voltmeter_demo_volts_gain.ino

@@ -3,6 +3,8 @@
 //  AUTHOR: Rob Tillaart
 // PURPOSE: demo DMM 
 //     URL: https://github.com/RobTillaart/DMM
+//
+//  add a 25 -> 5 volt converter before A0
 
 
 #include "DMM.h"
@@ -19,10 +21,14 @@ void setup()
   Serial.print("DMM_LIB_VERSION: ");
   Serial.println(DMM_LIB_VERSION);
 
-  dmm.begin(A0, 5, 1023);
+  dmm.begin(A0, 5.000, 1023);
 
   //  add a 25 -> 5 volt converter before A0
   dmm.setGain(5);
+
+  //  alternative
+  //  dmm.begin(A0, 25.000, 1023);
+
 }
 
 
@@ -39,4 +45,4 @@ void loop()
 }
 
 
-// -- END OF FILE --
+//  -- END OF FILE --

libraries/DMM/keywords.txt

@@ -17,6 +17,10 @@ readMilliVolts	KEYWORD2
 
 readNoise	KEYWORD2
 
+setReferenceR	KEYWORD2
+readOhm	KEYWORD2
+readKiloOhm	KEYWORD2
+
 
 # Constants (LITERAL1)
 DMM_LIB_VERSION	LITERAL1

libraries/DMM/library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/DMM.git"
   },
-  "version": "0.1.1",
+  "version": "0.1.2",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",

libraries/DMM/library.properties

@@ -1,5 +1,5 @@
 name=DMM
-version=0.1.1
+version=0.1.2
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=DMM (digital multimeter) library for Arduino.

libraries/DMM/test/unit_test_001.cpp

@@ -36,6 +36,7 @@ unittest_setup()
     fprintf(stderr, "DMM_LIB_VERSION: %s\n", (char *) DMM_LIB_VERSION);
 }
 
+
 unittest_teardown()
 {
 }
@@ -53,4 +54,4 @@ unittest(test_first)
 unittest_main()
 
 
-// -- END OF FILE --
+//  -- END OF FILE --