Category:

Code

Arduino Due and MCP3421 A/D converter example

by shedboy71 27th June 2019

written by shedboy71

The MCP3421 ADC can be used for various high accuracy analog-to-digital data conversion applications where ease of use, low power consumption and small footprint are major considerations.The MCP3421 is a single channel low-noise, high accuracy delta-sigma A/D converter with differential inputs and up to 18 bits of resolution in a small SOT-23-6 package.

The on-board precision 2.048V reference voltage enables a differential input range of ±2.048V. The device uses a two-wire I2C™ compatible interface and operates from a single power supply ranging from 2.7V to 5.5V. The MCP3421 ADC performs conversions at rates of 3.75, 15, 60 or 240 samples per second with corresponding resolutions of 18, 16, 14 and 12 bits. The onboard programmable gain amplifier (PGA) provides gain up to 8x. The device has two conversion modes: Continuous mode and One-Shot mode. In One-Shot mode, the device enters a low current standby mode automatically after a conversion, greatly reducing power use.

Features

- 18-bit resolution
- Small 6-lead SOT-23 packaging
- Differential input operation
- On-board voltage reference with 5 ppm/°C drift
- On-board PGA, gains of 1, 2, 4, 8
- Programmable data rate options
  - 3.75 SPS (18 bits)
  - 15 SPS (16 bits)
  - 60 SPS (14 bits)
  - 240 SPS (12 bits)
- INL 10 ppm of FSR max
- Low current consumption, 145 µA at 3V
- One-shot or continuous conversion options
- Supports I²C™ serial interface
- Extended temperature range: -40°C to +125°C

Parts List

Part	Link
MCP3421	MCP3421 I2C SOT23-6 delta-sigma ADC Evaluation Board
Connecting cable	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire Dupont cablefor Arduino
Arduino Due	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino

Connection

Its an I2C device – I connected the VIN- to Gnd and Vin+ to Pin 6

Arduino Due	VEML6040 module
3v3	Vcc
Gnd	Gnd
SDA – 20	SDA
SCL – 21	SCL

Code

You need to download and install the following library – https://github.com/uChip/MCP342X

[codesyntax lang=”cpp”]

// Include libraries this sketch will use
#include  <Wire.h>
#include  <MCP342X.h>

// Instantiate objects used in this project
MCP342X myADC;
int outputPin = 6;

void setup() 
{
  Wire.begin();  // join I2C bus
  TWBR = 12;  // 400 kHz (maximum)
  
  Serial.begin(9600); // Open serial connection to send info to the host
  while (!Serial) {}  // wait for Serial comms to become ready
  Serial.println("Starting up");
  Serial.println("Testing device connection...");
  Serial.println(myADC.testConnection() ? "MCP342X connection successful" : "MCP342X connection failed");
    
  myADC.configure( MCP342X_MODE_CONTINUOUS |
                   MCP342X_CHANNEL_1 |
                   MCP342X_SIZE_16BIT |
                   MCP342X_GAIN_1X
                 );

  Serial.println(myADC.getConfigRegShdw(), HEX);
  
}  // End of setup()

void loop() {
  static int16_t  result;
  for(int i=0; i<=255; i++)
  {
    myADC.startConversion();
    analogWrite(outputPin, i);
    myADC.getResult(&result);
    Serial.print(i);
    Serial.print("  ");
    Serial.print(result);
    Serial.print("  ");
    Serial.println(result, HEX);
  }
  
}  // End of loop()

[/codesyntax]

link

Datasheet – http://ww1.microchip.com/downloads/en/DeviceDoc/22003e.pdf

27th June 2019 0 comment

Arduino Due

Arduino Due : AM2320 temperature and humidity sensor

by shedboy71 11th June 2019

written by shedboy71

Temperature and humidity combined sensor AM2320 digital temperature and humidity sensor is a digital signal output has been calibrated. Using special temperature and humidity acquisition technology, ensure that the product has a very high reliability and excellent long-term stability. Sensor consists of a capacitive moisture element and an integrated high-precision temperature measurement devices, and connected with a high-performance microprocessor .

AM2320 communication using a single bus, two communication modes standard I2C. Standard single-bus interface, the system integration becomes easy and quick. Ultra-small size, low power consumption, signal transmission distance up to 20 meters, making all kinds of applications and even the most demanding applications the best choice. I2C communication using standard communication sequence, the user can directly linked to the I2C communication bus without additional wiring, simple to use. Two communication modes are used as humidity, temperature, and other digital information directly CRC checksum temperature-compensated output, users do not need to calculate the secondary digital output, and no need for temperature compensation of the humidity, temperature and humidity can be accurately information. Two communication modes are free to switch, the user can freely choose, easy to use, wide range of applications.

Specifications

• Operating Voltage: 3.1 VDC to 5.5 VDC
• Operating Temperature Range: -40 ° C to + 80 ° C
• Humidity Range: 0 to 99.9% RH
• Accuracy ( 25 ° C environment)
Temperature: ± 0.5 ° C
Humidity: ± 3%
• RH (10 … 90% RH)
Resolution: Temperature: 0.1 ° C
Resolution: Humidity: 0.1% RH
• Attenuation values
Temperature: <0.1 ℃ / Year
Humidity: <1% RH / Year
• Response time: Temperature: 5s
• Response Time: Humidity: 5s 1 / e (63%)
• Output signal: single bus / IIC signal
• Housing material: PC plastic

Parts List

name	Link
Arduino Due	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino
AM2320	AM2320 Digital Temperature&Humidity Sensor Module Single Bus I2C
connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Connection

Arduino Due	AM2320 module
3v3	+
Gnd	–
SDA – 20	SDA
SCL – 21	SCL

Code

You will need to install the folllowing library from https://github.com/EngDial/AM2320

This is the default example

[codesyntax lang=”cpp”]

#include <AM2320.h>

AM2320 th(&Wire);

void setup() {
  Serial.begin(9600);
  Wire.begin();
}

void loop() {
  Serial.println(F("Chip = AM2320"));
  switch(th.Read()) {
    case 2:
      Serial.println(F("  CRC failed"));
      break;
    case 1:
      Serial.println(F("  Sensor offline"));
      break;
    case 0:
      Serial.print(F("  Humidity = "));
      Serial.print(th.Humidity);
      Serial.println(F("%"));
      Serial.print(F("  Temperature = "));
      Serial.print(th.cTemp);
      Serial.println(F("*C"));
      Serial.println();
      break;
  }
  delay(2000);
}

[/codesyntax]

Output

Open the serial monitor

Chip = AM2320
Humidity = 29.90%
Temperature = 29.60*C

Chip = AM2320
Humidity = 30.10%
Temperature = 29.40*C

Chip = AM2320
Humidity = 30.30%
Temperature = 29.30*C

Links

AM2320 Digital Temperature and Humidity Sensor Replace AM2302 SHT10

https://akizukidenshi.com/download/ds/aosong/AM2320.pdf

11th June 2019 0 comment

Arduino Due

GY-21P module example connected to an Arduino Due

by shedboy71 28th May 2019

written by shedboy71

The GY-21P is a module that combines a BMP280 sensor and an SI7021 sensor. The on-board BMP280+SI7021 sensor measures atmospheric pressure from 30kPa to 110kPa as well as relative humidity and temperature.

A quick look at both sensors

BMP280
Pressure range: 300-1100 hPa (9000 meters above sea level at -500m)
Relative accuracy (at 950 – 1050 hPa at 25 ° C): ± 0.12 hPa, equiv. to ± 1 m
Absolute accuracy (at (950 – 1050 hPa, 0 – +40 ° C): ± 0.12 hPa, equiv. To ± 1 m
Mains voltage: 1.8V – 3.6V
Power consumption: 2.7µA at 1Hz readout rate
Temperature range: -40 to + 85 ° C

SI7021
HVAC/R
Thermostats/humidistats
Respiratory therapy
White goods
Indoor weather stations
Micro-environments/data centers
Automotive climate control and defogging
Asset and goods tracking
Mobile phones and tablets
Size: 1.3*1cm/0.51*0.39″

Features:

Operation Voltage: 3.3V
I2C & SPI Communications Interface
Temp Range: -40C to 85C
Humidity Range: 0 – 100% RH, =-3% from 20-80%
Pressure Range: 30,000Pa to 110,000Pa, relative accuracy of 12Pa, absolute accuracy of 100Pa
Altitude Range: 0 to 30,000 ft (9.2 km), relative accuracy of 3.3 ft (1 m) at sea level, 6.6 (2 m) at 30,000 ft.

Parts List

name	Link
Arduino Due	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino
GY-21p module	Atmospheric Humidity Temperature Sensor Breakout Barometric Pressure BMP280 SI7021 for Arduino GY-21P
connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Connection

Arduino Due	GY21-p module
3v3	Vin
Gnd	Gnd
20 – SDA	SDA
21 – SCL	SCL

Code

You need to use a variety of Adafruit libraries, i basically took the default examples and made the following out of them

https://github.com/adafruit/Adafruit_Sensor

https://github.com/adafruit/Adafruit_BMP280_Library

https://github.com/adafruit/Adafruit_Si7021

[codesyntax lang=”cpp”]

#include <Wire.h>
#include <Adafruit_Sensor.h>
#include <Adafruit_BMP280.h>
#include "Adafruit_Si7021.h"

Adafruit_BMP280 bme; // I2C
Adafruit_Si7021 sensor = Adafruit_Si7021();

void setup() 
{
Serial.begin(9600);
Serial.println("BMP280 and SI7021 (GY-21p) test");

if (!bme.begin()) 
{ 
Serial.println("Could not find a valid BMP280 sensor, check wiring!");
while (1);
}

if (!sensor.begin()) 
{
Serial.println("Did not find Si7021 sensor!");
while (true);
}
}

void loop() 
{
Serial.println("BMP280 results");
Serial.print("Temperature = ");
Serial.print(bme.readTemperature());
Serial.println(" *C");
Serial.print("Pressure = ");
Serial.print(bme.readPressure());
Serial.println(" Pa");
Serial.print("Approx altitude = ");
Serial.print(bme.readAltitude(1013.25)); // this should be adjusted to your local forcase
Serial.println(" m");
Serial.println();

Serial.println("SI7021 results");
Serial.print("Humidity: "); 
Serial.println(sensor.readHumidity(), 2);
Serial.print("Temperature: "); 
Serial.println(sensor.readTemperature(), 2);
Serial.println();
delay(2000);
}

[/codesyntax]

Output

OPen the serial monitor

BMP280 results
Temperature = 27.26 *C
Pressure = 99042.63 Pa
Approx altitude = 191.78 m

SI7021 results
Humidity: 31.04
Temperature: 27.30

BMP280 results
Temperature = 28.43 *C
Pressure = 99044.82 Pa
Approx altitude = 191.60 m

SI7021 results
Humidity: 32.59
Temperature: 28.56

BMP280 results
Temperature = 28.17 *C
Pressure = 99037.41 Pa
Approx altitude = 192.22 m

SI7021 results
Humidity: 32.88
Temperature: 28.46

You can see the temperature output is close between the sensors

Links

Atmospheric Humidity Temperature Sensor Breakout Barometric Pressure BMP280 SI7021 for Arduino

28th May 2019 0 comment

Arduino Due

Arduino Due and BMP280 barometric pressure sensor example

by shedboy71 10th May 2019

written by shedboy71

BMP280 is an absolute barometric pressure sensor especially designed for mobile applications. The sensor module is housed in an extremely compact package. Its small dimensions and its low power consumption allow for the implementation in battery powered devices such as mobile phones, GPS modules or watches.

As its predecessor BMP180, BMP280 is based on Bosch’s proven Piezo-resistive pressure sensor technology featuring high accuracy and linearity as well as long term stability and high EMC robustness. Numerous device operation options offer highest flexibility to optimize the device regarding power consumption, resolution and filter performance. A tested set of default settings for example use case is provided to the developer in order to make design-in as easy as possible.

Applications

– Enhancement of GPS navigation (e.g. time-tofirst-fix improvement, dead-reckoning, slope detection)

– Indoor navigation (floor detection, elevator detection)

– Outdoor navigation, leisure and sports applications

– Weather forecast

– Health care applications (e.g. spirometry)

– Vertical velocity indication (e.g. rise/sink speed)

Parameter	Technical data
Operation range (full accuracy)	Pressure: 300…1100 hPa Temperature: -40…85°C
Absolute accuracy (Temp. @ 0…+65°C)	~ ±1 hPa
Relative accuracy p = 700…900hPa (Temp. @ +25…+40°C)	± 0.12 hPa (typical) equivalent to ±1 m
Average current consumption (1 Hz data refresh rate)	2.74 μA, typical (ultra-low power mode)
Average current consumption in sleep mode	0.1 μA
Average measurement time	5.5 msec (ultra-low power preset)
Supply voltage VDDIO	1.2 … 3.6 V
Supply voltage VDD	1.71 … 3.6 V
Resolution of data	Pressure: 0.01 hPa ( < 10 cm) Temperature: 0.01° C
Temperature coefficient offset (+25°…+40°C @900hPa)	± 0.12 hPa (typical) equivalent to ±1 m
Interface	I²C and SPI

Parts List

name	Link
Arduino DUE	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino
GY-21p module	Atmospheric Humidity Temperature Sensor Breakout Barometric Pressure BMP280 SI7021 for Arduino GY-21P
connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Layout

This is a layout diagram using an adafruit part, my module had clearly marked SDA and SCL connections and no SPI connection

arduino due and bmp280

Code

No libraries needed – this is a controleverything example. There are many libraries if you would rather use one of those

[codesyntax lang=”cpp”]

// Distributed with a free-will license.
// Use it any way you want, profit or free, provided it fits in the licenses of its associated works.
// BMP280
// This code is designed to work with the BMP280_I2CS I2C Mini Module available from ControlEverything.com.
// https://www.controleverything.com/content/Barometer?sku=BMP280_I2CSs#tabs-0-product_tabset-2

#include<Wire.h>

// BMP280 I2C address is 0x76(108)
#define Addr 0x76

void setup()
{
  // Initialise I2C communication as MASTER
  Wire.begin();
  // Initialise Serial communication, set baud rate = 9600
  Serial.begin(9600);
}

void loop()
{
  unsigned int b1[24];
  unsigned int data[8];
  for (int i = 0; i < 24; i++)
  {
    // Start I2C Transmission
    Wire.beginTransmission(Addr);
    // Select data register
    Wire.write((136 + i));
    // Stop I2C Transmission
    Wire.endTransmission();

    // Request 1 byte of data
    Wire.requestFrom(Addr, 1);

    // Read 1 byte of data
    if (Wire.available() == 1)
    {
      b1[i] = Wire.read();
    }
  }
  // Convert the data
  // temp coefficients
  unsigned int dig_T1 = (b1[0] & 0xFF) + ((b1[1] & 0xFF) * 256);
  int dig_T2 = b1[2] + (b1[3] * 256);
  int dig_T3 = b1[4] + (b1[5] * 256);

  // pressure coefficients
  unsigned int dig_P1 = (b1[6] & 0xFF) + ((b1[7] & 0xFF) * 256);
  int dig_P2 = b1[8] + (b1[9] * 256);
  int dig_P3 = b1[10] + (b1[11] * 256);
  int dig_P4 = b1[12] + (b1[13] * 256);
  int dig_P5 = b1[14] + (b1[15] * 256);
  int dig_P6 = b1[16] + (b1[17] * 256);
  int dig_P7 = b1[18] + (b1[19] * 256);
  int dig_P8 = b1[20] + (b1[21] * 256);
  int dig_P9 = b1[22] + (b1[23] * 256);

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select control measurement register
  Wire.write(0xF4);
  // Normal mode, temp and pressure over sampling rate = 1
  Wire.write(0x27);
  // Stop I2C Transmission
  Wire.endTransmission();

  // Start I2C Transmission
  Wire.beginTransmission(Addr);
  // Select config register
  Wire.write(0xF5);
  // Stand_by time = 1000ms
  Wire.write(0xA0);
  // Stop I2C Transmission
  Wire.endTransmission();

  for (int i = 0; i < 8; i++)
  {
    // Start I2C Transmission
    Wire.beginTransmission(Addr);
    // Select data register
    Wire.write((247 + i));
    // Stop I2C Transmission
    Wire.endTransmission();

    // Request 1 byte of data
    Wire.requestFrom(Addr, 1);

    // Read 1 byte of data
    if (Wire.available() == 1)
    {
      data[i] = Wire.read();
    }
  }

  // Convert pressure and temperature data to 19-bits
  long adc_p = (((long)(data[0] & 0xFF) * 65536) + ((long)(data[1] & 0xFF) * 256) + (long)(data[2] & 0xF0)) / 16;
  long adc_t = (((long)(data[3] & 0xFF) * 65536) + ((long)(data[4] & 0xFF) * 256) + (long)(data[5] & 0xF0)) / 16;

  // Temperature offset calculations
  double var1 = (((double)adc_t) / 16384.0 - ((double)dig_T1) / 1024.0) * ((double)dig_T2);
  double var2 = ((((double)adc_t) / 131072.0 - ((double)dig_T1) / 8192.0) *
                 (((double)adc_t) / 131072.0 - ((double)dig_T1) / 8192.0)) * ((double)dig_T3);
  double t_fine = (long)(var1 + var2);
  double cTemp = (var1 + var2) / 5120.0;
  double fTemp = cTemp * 1.8 + 32;

  // Pressure offset calculations
  var1 = ((double)t_fine / 2.0) - 64000.0;
  var2 = var1 * var1 * ((double)dig_P6) / 32768.0;
  var2 = var2 + var1 * ((double)dig_P5) * 2.0;
  var2 = (var2 / 4.0) + (((double)dig_P4) * 65536.0);
  var1 = (((double) dig_P3) * var1 * var1 / 524288.0 + ((double) dig_P2) * var1) / 524288.0;
  var1 = (1.0 + var1 / 32768.0) * ((double)dig_P1);
  double p = 1048576.0 - (double)adc_p;
  p = (p - (var2 / 4096.0)) * 6250.0 / var1;
  var1 = ((double) dig_P9) * p * p / 2147483648.0;
  var2 = p * ((double) dig_P8) / 32768.0;
  double pressure = (p + (var1 + var2 + ((double)dig_P7)) / 16.0) / 100;

  // Output data to serial monitor
  Serial.print("Pressure : ");
  Serial.print(pressure);
  Serial.println(" hPa");
  Serial.print("Temperature in Celsius : ");
  Serial.print(cTemp);
  Serial.println(" C");
  Serial.print("Temperature in Fahrenheit : ");
  Serial.print(fTemp);
  Serial.println(" F");
  delay(1000);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this – I sometimes get strange altitude readings – negative values, not sure why

Temperature in Celsius : 21.31 C
Temperature in Fahrenheit : 70.36 F
Pressure : 1331.70 hPa
Temperature in Celsius : 21.30 C
Temperature in Fahrenheit : 70.34 F
Pressure : 1331.70 hPa
Temperature in Celsius : 21.30 C
Temperature in Fahrenheit : 70.34 F
Pressure : 1331.26 hPa
Temperature in Celsius : 21.31 C
Temperature in Fahrenheit : 70.36 F
Pressure : 1331.04 hPa

Link

https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP280-DS001-18.pdf

1 piece I2C/SPI BMP280 3.3 Digital Barometric Pressure Altitude Sensor Module High Precision Atmospheric Module for Arduino

10th May 2019 0 comment

Arduino Due

Arduino Due and BME680 environmental sensor example

by shedboy71 30th April 2019

written by shedboy71

In this article we will connect a BME680 sensor to an Arduino Due

BME680 is an integrated environmental sensor developed specifically for mobile applications and wearables where size and low power consumption are key requirements. Expanding Bosch Sensortec’s existing family of environmental sensors, the BME680 integrates for the first time high-linearity and high-accuracy gas, pressure, humidity and temperature sensors. The gas sensor within the BME680 can detect a broad range of gases to measure air quality for personal well being.

This is the sensor that I purchased

Gases that can be detected by the BME680 include Volatile Organic Compounds (VOC) from paints (such as formaldehyde), lacquers, paint strippers, cleaning supplies, furnishings, office equipment, glues, adhesives and alcohol.

Parameter	Technical data
Package dimensions	8-Pin LGA with metal 3.0 x 3.0 x 0.93 mm³
Operation range (full accuracy)	Pressure: 300…1100 hPa Humidity 0…100% Temperature: -40…85°C
Supply voltage V_DDIO Supply voltage V_DD	1.2 … 3.6 V 1.71 … 3.6 V
Interface	I²C and SPI
Average current consumption (1Hz data refresh rate)	2.1 µA at 1 Hz humidity and temperature 3.1 µA at 1 Hz pressure and temperature 3.7 µA at 1 Hz humidity, pressure and temperature 0.09‒12 mA for p/h/T/gas depending on operation mode
Average current consumption in sleep mode	0.15 μA
Gas sensor Response time (τ 33-63%) Sensor-to-sensor deviation Power consumption Output data processing	< 1 s (for new sensors) +/- 15% +/- 15 < 0.1 mA in ultra-low power mode direct output of IAQ: Index for Air Quality
Humidity sensor Response time (τ0-63%) Accuracy tolerance Hysteresis	8 s ± 3 % relative humidity ≤ 1.5 % relative humidity
Pressure sensor RMS Noise Sensitivity Error Temperature coefficient offset	0.12 Pa (equiv. to 1.7 cm) ± 0.25 % (equiv. to 1 m at 400 m height change) ±1.3 Pa/K (equiv. to ±10.9 cm at 1°C temperature change)

Parts List

Name	Link
Arduino Due	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino
BME680	BME680 Sensor Module Temperature and Humidity Air Pressure Air Quality IAQ MCU680 Module
Connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Schematic

We use the I2C connection for the sensor

arduino due and bme680

Code

You will need to import the adafruit unified sensor and bme680 libraries for this example – you can add these using the library manager

My particular sensor which you can see in the picture earlier in the article used address 0x76, the default is 0x77 so you may have to change this line from if (!bme.begin(0x76)) to if (!bme.begin())

[codesyntax lang=”cpp”]

#include <Wire.h>
#include <SPI.h>
#include <Adafruit_Sensor.h>
#include "Adafruit_BME680.h"


#define SEALEVELPRESSURE_HPA (1013.25)

Adafruit_BME680 bme; // I2C

void setup() {
  Serial.begin(9600);
  while (!Serial);
  Serial.println(F("BME680 test"));

  if (!bme.begin(0x76)) 
  {
    Serial.println("Could not find a valid BME680 sensor, check wiring!");
    while (1);
  }

  // Set up oversampling and filter initialization
  bme.setTemperatureOversampling(BME680_OS_8X);
  bme.setHumidityOversampling(BME680_OS_2X);
  bme.setPressureOversampling(BME680_OS_4X);
  bme.setIIRFilterSize(BME680_FILTER_SIZE_3);
  bme.setGasHeater(320, 150); // 320*C for 150 ms
}

void loop() 
{
  if (! bme.performReading()) 
  {
    Serial.println("Failed to perform reading :(");
    return;
  }
  Serial.print("Temperature = ");
  Serial.print(bme.temperature);
  Serial.println(" *C");

  Serial.print("Pressure = ");
  Serial.print(bme.pressure / 100.0);
  Serial.println(" hPa");

  Serial.print("Humidity = ");
  Serial.print(bme.humidity);
  Serial.println(" %");

  Serial.print("Gas = ");
  Serial.print(bme.gas_resistance / 1000.0);
  Serial.println(" KOhms");

  Serial.print("Approx. Altitude = ");
  Serial.print(bme.readAltitude(SEALEVELPRESSURE_HPA));
  Serial.println(" m");

  Serial.println();
  delay(2000);
}

[/codesyntax]

Output

Open the serial monitor and you will see something like this

30th April 2019 0 comment

Arduino Due

Arduino Due and TMP102 digital temperature sensor example

by shedboy71 10th April 2019

written by shedboy71

In this article we look at the TMP102 digital sensor and we will connect it up to an Arduino Due

The TMP102 device is a digital temperature sensor ideal for NTC/PTC thermistor replacement where high accuracy is required. The device offers an accuracy of ±0.5°C without requiring calibration or external component signal conditioning. Device temperature sensors are highly linear and do not require complex calculations or lookup tables to derive the temperature. The on-chip 12-bit ADC offers resolutions down to 0.0625°C.

The TMP102 device features SMBus™, two-wire and I²C interface compatibility, and allows up to four devices on one bus. The device also features an SMBus alert function. The device is specified to operate over supply voltages from 1.4 to 3.6 V with the maximum quiescent current of 10 µA over the full operating range.

The TMP102 device is ideal for extended temperature measurement in a variety of communication, computer, consumer, environmental, industrial, and instrumentation applications. The device is specified for operation over a temperature range of –40°C to 125°C.

Layout

Another easy device to connect to our Arduino Due as you can see below

arduino due and TMP102

Parts List

Name	Link
Arduino Due	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino
TMP102 breakout	TMP102 Digital Temperature Sensor Breakout Board Module 12-bit 1.4V To 3.6VDC Sensor Module Temperature Module
connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Code

This is from the Arduino site with a few tweaks

[codesyntax lang=”cpp”]

#include "Wire.h"
#define TMP102_I2C_ADDRESS 72 /* This is the I2C address for our chip. This value is correct if you tie the ADD0 pin to ground. See the datasheet for some other values. */


void setup() 
{
  Wire.begin(); // start the I2C library
  Serial.begin(115200); //Start serial communication at 115200 baud
}


void loop() 
{
  getTemp102();
  delay(5000); //wait 5 seconds before printing our next set of readings. 
}

void getTemp102()
{
  byte firstbyte, secondbyte; //these are the bytes we read from the TMP102 temperature registers
  int val; /* an int is capable of storing two bytes, this is where we "chuck" the two bytes together. */ 
  float convertedtemp; /* We then need to multiply our two bytes by a scaling factor, mentioned in the datasheet. */ 
  float correctedtemp; 

  /* Reset the register pointer (by default it is ready to read temperatures)
You can alter it to a writeable register and alter some of the configuration - 
the sensor is capable of alerting you if the temperature is above or below a specified threshold. */

  Wire.beginTransmission(TMP102_I2C_ADDRESS); //Say hi to the sensor. 
  Wire.write(0x00);
  Wire.endTransmission();
  Wire.requestFrom(TMP102_I2C_ADDRESS, 2);
  Wire.endTransmission();


  firstbyte      = (Wire.read()); 
  /*read the TMP102 datasheet - here we read one byte from
   each of the temperature registers on the TMP102*/
  secondbyte     = (Wire.read()); 
  /*The first byte contains the most significant bits, and 
   the second the less significant */
    val = firstbyte;
    if ((firstbyte & 0x80) > 0) 
    {
      val |= 0x0F00;
    } 
    val <<= 4; 
 /* MSB */
    val |= (secondbyte >> 4);    
/* LSB is ORed into the second 4 bits of our byte.
Bitwise maths is a bit funky, but there's a good tutorial on the playground*/
    convertedtemp = val*0.0625;
    correctedtemp = convertedtemp - 5; 
    /* See the above note on overreading */


  Serial.print("firstbyte is ");
  Serial.print("\t");
  Serial.println(firstbyte, BIN);
  Serial.print("secondbyte is ");
  Serial.print("\t");
  Serial.println(secondbyte, BIN);
  Serial.print("Concatenated byte is ");
  Serial.print("\t");
  Serial.println(val, BIN);
  Serial.print("Converted temp is ");
  Serial.print("\t");
  Serial.println(val*0.0625);
  Serial.print("Corrected temp is ");
  Serial.print("\t");
  Serial.println(correctedtemp);
  Serial.println();
}

[/codesyntax]

Output

Open the serial monitor window and you should see something like this

firstbyte is 10100
secondbyte is 1110000
Concatenated byte is 101000111
Converted temp is 20.44
Corrected temp is 15.44

firstbyte is 10100
secondbyte is 1100000
Concatenated byte is 101000110
Converted temp is 20.37
Corrected temp is 15.38

Link

http://www.ti.com/lit/gpn/tmp102

10th April 2019 0 comment

Arduino Due

Arduino Due and Si1145 sensor example

by shedboy71 30th March 2019

written by shedboy71

In this exampl;e we look at the Si1145 sensor, we connect it to an Arduino Due and use the Arduino IDE for development

First the sensor in a little more detail

The Si1145/46/47 is a low-power, reflectance-based, infrared proximity, ultraviolet (UV) index, and ambient light sensor with I2C digital interface and programmable event interrupt output. This touchless sensor IC includes an analog-to-digital converter, integrated high-sensitivity visible and infrared photodiodes, digital signal processor, and one, two, or three integrated infrared LED drivers with fifteen selectable drive levels. The Si1145/46/47 offers excellent performance under a wide dynamic range and a variety of light sources including direct sunlight. The Si1145/46/47 can also work under dark glass covers.

The photodiode response and associated digital conversion circuitry provide excellent immunity to artificial light flicker noise and natural light flutter noise. With two or more LEDs, the Si1146/47 is capable of supporting multiple-axis proximity motion detection. The Si1145/46/47 devices are provided in a 10-lead 2×2 mm QFN package and are capable of operation from 1.71 to 3.6 V over the –40 to +85 °C temperature range.

Parts List

name	Link
Arduino Due	Black Due R3 Board DUE-CH340 ATSAM3X8E ARM Main Control Board with 50cm USB Cable CH340G for arduino
Si1145 breakout	SI1145 UV IR Visible Sensor I2C GY1145 Light Breakout Board Module
connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Layout

Simple to connect being an I2C device – I used 3v3 on my sesnor

arduino due and si1145

Code

This example requires the Adafruit Si1145 library, you can add this via the library manager or download from https://github.com/adafruit/Adafruit_SI1145_Library

[codesyntax lang=”cpp”]

#include <Wire.h>
#include "Adafruit_SI1145.h"

Adafruit_SI1145 uv = Adafruit_SI1145();

void setup() {
  Serial.begin(9600);
  
  Serial.println("Adafruit SI1145 test");
  
  if (! uv.begin()) {
    Serial.println("Didn't find Si1145");
    while (1);
  }

  Serial.println("OK!");
}

void loop() {
  Serial.println("===================");
  Serial.print("Vis: "); Serial.println(uv.readVisible());
  Serial.print("IR: "); Serial.println(uv.readIR());
  
  // Uncomment if you have an IR LED attached to LED pin!
  //Serial.print("Prox: "); Serial.println(uv.readProx());

  float UVindex = uv.readUV();
  // the index is multiplied by 100 so to get the
  // integer index, divide by 100!
  UVindex /= 100.0;  
  Serial.print("UV: ");  Serial.println(UVindex);

  delay(1000);
}

[/codesyntax]

Output

Open the serial monitor window – these readings were taken indoors

Adafruit SI1145 test
OK!
===================
Vis: 256
IR: 281
UV: 0.02
===================
Vis: 263
IR: 280
UV: 0.03
===================
Vis: 261
IR: 279
UV: 0.02
===================

Link

https://www.silabs.com/documents/public/data-sheets/Si1145-46-47.pdf

30th March 2019 0 comment

Micropython

Flashing the onboard LEDs on a PyBoard

by shedboy71 11th March 2019

written by shedboy71

The Pyboard comes with 4 on board LEDs, in this example we will flash them on and off, the example was written in uPyCraft

Pinouts

Parts List

Name	Link
Elecrow PyBoard	Elecrow Core Board For MicroPython Crow Pyboard Development Board STM32F405RG for Pyboard Python Learning Module Microcontroller

Code

First of all the various methods from the official docs

LED.intensity([value])

Get or set the LED intensity. Intensity ranges between 0 (off) and 255 (full on). If no argument is given, return the LED intensity. If an argument is given, set the LED intensity and return None.

Note: Only LED(3) and LED(4) can have a smoothly varying intensity, and they use timer PWM to implement it. LED(3) uses Timer(2) and LED(4) uses Timer(3). These timers are only configured for PWM if the intensity of the relevant LED is set to a value between 1 and 254. Otherwise the timers are free for general purpose use.

LED.off(): Turn the LED off.

LED.on(): Turn the LED on, to maximum intensity.

LED.toggle(): Toggle the LED between on (maximum intensity) and off. If the LED is at non-zero intensity then it is considered “on” and toggle will turn it off.

Now for the example showing this

[codesyntax lang=”python”]

from pyb import LED
import time

led1 = LED(1) # 1=red, 2=green, 3=yellow, 4=blue
led1.toggle()
led1.on()
time.sleep(1)
led1.off()
time.sleep(1)

led2 = LED(2) # 1=red, 2=green, 3=yellow, 4=blue
led2.toggle()
led2.on()
time.sleep(1)
led2.off()
time.sleep(1)

led3 = LED(3) # 1=red, 2=green, 3=yellow, 4=blue
led3.toggle()
led3.on()
time.sleep(1)
led3.off()
time.sleep(1)

led4 = LED(4) # 1=red, 2=green, 3=yellow, 4=blue
led4.toggle()
led4.on()
time.sleep(1)
led4.off()
time.sleep(1)

# LEDs 3 and 4 support PWM intensity (0-255)
LED(4).intensity()    # get intensity
LED(4).intensity(25) # set intensity to 25

[/codesyntax]

11th March 2019 0 comment

Micropython

Pyboard Micropython I2C Scanner

by shedboy71 25th February 2019

written by shedboy71

This is a simple very short code example in which we show how to create a basic I2CScanner in Micropython using the uPyCraft IDE for a Pyboard

The arduino equivalent is one that I use frequently and is one of the most useful sketches for figuring out why a sensor may not be working correctly with a library or code – usually because the default I2C address differs from the sensor address that you buy

Layout

An example connecting a sensor to a Pyboard

Code

[codesyntax lang=”python”]

from pyb import I2C

i2c = I2C(1, I2C.MASTER, baudrate=100000)
print('Scan i2c bus...')
devices = i2c.scan()

if len(devices) == 0:
  print("No i2c device !")
else:
  print('i2c devices found:',len(devices))
  
for device in devices:  
  print("Decimal address: ",device)
  print("Hex address: ",hex(device))

[/codesyntax]

Output

All going well you should output like the following in uPyCraft – this is a TMP175 connected to a PyBoard (not a BMP180 as the layout earlier)

Ready to download this file,please wait!
…
download ok
exec(open(‘i2cscanner.py’).read(),globals())
Scan i2c bus…
i2c devices found: 1
Decimal address: 55
Hex address: 0x37
>>>

25th February 2019 0 comment

Code Hardware

A look at the STM32F4DISCOVERY with an Arduino based example

by shedboy71 5th February 2019

written by shedboy71

In this example we look at the STM32F4DISCOVERY and in particular the STM32F407G-DISC1

Lets look at some key features

The STM32F4DISCOVERY kit leverages the capabilities of the STM32F407 high performance microcontrollers, to allow users to easily develop applications featuring audio.

It includes an ST-LINK embedded debug tool, one ST-MEMS digital accelerometer, a digital microphone, one audio DAC with integrated class D speaker driver, LEDs, push-buttons and an USB OTG micro-AB connector.

With the latest board enhancement, the new order code STM32F407G-DISC1 has replaced the old reference STM32F4DISCOVERY.

Key Features

STM32F407VGT6 microcontroller featuring 32-bit ARM^®Cortex^®-M4 with FPU core, 1-Mbyte Flash memory, 192-Kbyte RAM in an LQFP100 package
On-board ST-LINK/V2 on STM32F4DISCOVERY (old reference) or ST-LINK/V2-A on STM32F407G-DISC1 (new order code)
USB ST-LINK with re-enumeration capability and three different interfaces:
- Debug port
- Virtual Com port (with new order code only)
- Mass storage (with new order code only)
Board power supply: through USB bus or from an external 5 V supply voltage
External application power supply: 3 V and 5 V
LIS302DL or LIS3DSH ST MEMS 3-axis accelerometer
MP45DT02 ST-MEMS audio sensor omni-directional digital microphone
CS43L22 audio DAC with integrated class D speaker driver
Eight LEDs:
- LD1 (red/green) for USB communication
- LD2 (red) for 3.3 V power on
- Four user LEDs, LD3 (orange), LD4 (green), LD5 (red) and LD6 (blue)
- 2 USB OTG LEDs LD7 (green) VBUS and LD8 (red) over-current
Two push-buttons (user and reset)
USB OTG FS with micro-AB connector
Extension header for all LQFP100 I/Os for quick connection to prototyping board and easy probing
Comprehensive free software including a variety of examples, part of STM32CubeF4 package or STSW-STM32068 to use legacy standard libraries.

There are 4 coloured LEDs on the STM32F407G-DISC1 development board as stated above, these are locate dunder the microcontroller

PIN	NAME	COLOUR	POSITION
PD13	LD3	ORANGE	UP
PD14	LD5	RED	RIGHT
PD15	LD6	BLUE	DOWN
PD12	LD4	GREEN	LEFT

Parts List

STM32F4DISCOVERY Embeded ST-LINK/V2 STM32 Evaluation Development Board,Free shipping

Code

We used Atom IDE with Platform.IO installed and added support for the STM32 boards. This is an Arduino example (confused). You could add STM32 support to the Arduino IDE by adding stm32duino support but I like the look of Platform IDE so wanted to play about with the IDE

This is a fairly basic example to flash the LEDS off and on repeatedly

[codesyntax lang=”cpp”]

#include <Arduino.h>

void setup() {
  // put your setup code here, to run once:

  // Set the MCU's pin data direction.
  pinMode(PD13, OUTPUT);
  pinMode(PD14, OUTPUT);
  pinMode(PD15, OUTPUT);
  pinMode(PD12, OUTPUT);

  // Set all outputs LOW to have all LED's initially turned off.
  digitalWrite(PD13, LOW);
  digitalWrite(PD14, LOW);
  digitalWrite(PD15, LOW);
  digitalWrite(PD12, LOW);
}

void loop() {
  // put your main code here, to run repeatedly:

  // Turn off the GREEN LED, turn on the ORANGE LED and wait for 1000ms.
  digitalWrite(PD12, HIGH);
  digitalWrite(PD13, HIGH);
  digitalWrite(PD14, HIGH);
  digitalWrite(PD15, HIGH);
  delay(1000);

  digitalWrite(PD12, LOW);
  digitalWrite(PD13, LOW);
  digitalWrite(PD14, LOW);
  digitalWrite(PD15, LOW);
  delay(1000);

  // The code in the "loop()" statement will automatically repeat.
}

[/codesyntax]

Link

https://www.st.com/en/evaluation-tools/stm32f4discovery.html

5th February 2019 0 comment

Code

A look at the Arch from Seeed

by shedboy71 16th January 2019

written by shedboy71

In this article we look at the Arch from Seeed. Its an MBed compatible board with Arduino headers fitted and is reasonably low cost

Features

NXP LPC11U24 MCU
Low power ARM Cortex-M0 Core
48MHz, 32KB Flash, 8KB RAM, 4KB EEPROM
USB Device, 2xSPI, UART, I2C

Here is a pinout of the Arch

Code

Some simple flashy LED examples that use the mbed online compiler

To program the device you do the following

The button of Arch is specially designed to provide two functions:

Quick press to reset
Long press to enter USB ISP mode, a CRP DISABLD disk will pop up.
On Windows, replace firmware.bin with your program binary file generated from the MBed compiler

Example 1

[codesyntax lang=”cpp”]

#include "mbed.h"

DigitalOut myled1(LED1);
DigitalOut myled2(LED2);
DigitalOut myled3(LED3);
DigitalOut myled4(LED4);

int main() {
    while(1) {
        myled1 = 1;
        wait(0.2);
        myled1 = 0;
        wait(0.2);
        myled2 = 1;
        wait(0.5);
        myled2 = 0;
        wait(0.2);
        myled3 = 1;
        wait(0.7);
        myled3 = 0;
        wait(0.2);
        myled4 = 1;
        wait(0.9);
        myled4 = 0;
        wait(0.2);
    }
}

[/codesyntax]

Example 2

[codesyntax lang=”cpp”]

#include "mbed.h"

DigitalOut myled1(LED1);
DigitalOut myled2(LED2);
DigitalOut myled3(LED3);
DigitalOut myled4(LED4);

int main() {
    while(1) {
        myled1 = 1;
        myled2 = 1;
        myled3 = 1;
        myled4 = 1;
        wait(0.5);
        myled1 = 0;
        myled2 = 0;
        myled3 = 0;
        myled4 = 0;
        wait(0.5);

    }
}

[/codesyntax]

We will use this for MBed examples

16th January 2019 0 comment

Arduino Due

Arduino Due and VEML6075 sensor

by shedboy71 7th January 2019

written by shedboy71

Another VEML sensor, this time its a VEML6075 and again we connect it to an Arduino Due

The VEML6075 senses UVA and UVB light and incorporates photodiode, amplifiers, and analog / digital circuits into a single chip using a CMOS process. When the UV sensor is applied, it is able to detect UVA and UVB intensity to provide a measure of the signal strength as well as allowing for UVI measurement.

The VEML6075 provides excellent temperature compensation capability for keeping the output stable under changing temperature. VEML6075’s functionality is easily operated via the simple command format of I2C (SMBus compatible) interface protocol. VEML6075’s operating voltage ranges from 1.7 V to 3.6 V.

Parts List

Amount	Part Type
1	VEML6075
1	Compatible DUE R3 Board SAM3X8E 32-bit ARM Cortex-M3

Layout

arduino due and VEML6075 layout

Code

Again we use a library and again its an adafruit one

This is the full example

[codesyntax lang=”cpp”]

#include <Wire.h>
#include "Adafruit_VEML6075.h"

Adafruit_VEML6075 uv = Adafruit_VEML6075();

void setup() {
  Serial.begin(115200);
  Serial.println("VEML6075 Full Test");
  if (! uv.begin()) {
    Serial.println("Failed to communicate with VEML6075 sensor, check wiring?");
  }
  Serial.println("Found VEML6075 sensor");

  // Set the integration constant
  uv.setIntegrationTime(VEML6075_100MS);
  // Get the integration constant and print it!
  Serial.print("Integration time set to ");
  switch (uv.getIntegrationTime()) {
    case VEML6075_50MS: Serial.print("50"); break;
    case VEML6075_100MS: Serial.print("100"); break;
    case VEML6075_200MS: Serial.print("200"); break;
    case VEML6075_400MS: Serial.print("400"); break;
    case VEML6075_800MS: Serial.print("800"); break;
  }
  Serial.println("ms");

  // Set the high dynamic mode
  uv.setHighDynamic(false);
  // Get the mode
  if (uv.getHighDynamic()) {
    Serial.println("High dynamic reading mode");
  } else {
    Serial.println("Normal dynamic reading mode");
  }

  // Set the mode
  uv.setForcedMode(false);
  // Get the mode
  if (uv.getForcedMode()) {
    Serial.println("Forced reading mode");
  } else {
    Serial.println("Continuous reading mode");
  }

  // Set the calibration coefficients
  uv.setCoefficients(2.22, 1.33,  // UVA_A and UVA_B coefficients
                     2.95, 1.74,  // UVB_C and UVB_D coefficients
                     0.001461, 0.002591); // UVA and UVB responses
}


void loop() {
  Serial.print("Raw UVA reading:  "); Serial.println(uv.readUVA());
  Serial.print("Raw UVB reading:  "); Serial.println(uv.readUVB());
  Serial.print("UV Index reading: "); Serial.println(uv.readUVI());

  delay(1000);
}

[/codesyntax]

Output

Open the serial monitor – this is what I saw but I tested this indoors

VEML6075 Full Test
Failed to communicate with VEML6075 sensor, check wiring?
Found VEML6075 sensor
Integration time set to 50ms
Normal dynamic reading mode
Continuous reading mode
Raw UVA reading: 0.00
Raw UVB reading: 0.00
UV Index reading: 0.00
Raw UVA reading: 0.00
Raw UVB reading: 0.00
UV Index reading: 0.00

Links

https://www.vishay.com/docs/84304/veml6075.pdf

I2C Interface 3.3V Board Based on VEML6075 UVA UVB Light Sensor Module

7th January 2019 0 comment

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