Tag:

arduino

STM32 Nucleo and HDC2080 sensor example using the Arduino IDE

by shedboy71 29th May 2020

written by shedboy71

In this article we look at yet a HDC2080 humidity and temperature sensor from TI – we will connect up to an STM32 Nucleo and the example will again be using the Arduino IDE

Lets look at some of the technical information and data from TI

HDC2080 Information

The HDC2080 device is an integrated humidity and temperature sensor that provides high accuracy measurements with very low power consumption in a small DFN package. The capacitive-based sensor includes new integrated digital features and a heating element to dissipate condensation and moisture.

The HDC2080 digital features include programmable interrupt thresholds to provide alerts and system wake-ups without requiring a microcontroller to be continuously monitoring the system. Combined with programmable sampling intervals, a low power consumption, and a support for a 1.8-V supply voltage, the HDC2080 is designed for battery-operated systems.

The HDC2080 provides high accuracy measurement capability for a wide range of environmental monitoring and Internet of Things (IoT) applications such as smart thermostats and smart home assistants.

For applications with strict power-budget restrictions, Auto Measurement Mode enables the HDC2080 to automatically initiate temperature and humidity measurements. This feature allows users to configure a microcontroller into deep sleep mode because the HDC2080 is no longer dependent upon the microcontroller to initiate a measurement.

Programmable temperature and humidity thresholds in the HDC2080 allow the device to send a hardware interrupt to wake up the microcontroller when necessary. In addition, the power consumption of the HDC2080 is significantly reduced, which helps to minimize self-heating and improve measurement accuracy.

The HDC2080 is factory-calibrated to 0.2°C temperature accuracy and 2% relative humidity accuracy.

Features

Relative humidity range: 0% to 100%
Humidity accuracy: ±2% (typical), ±3% (maximum)
Temperature accuracy: ±0.2°C (typical), ±0.4°C (maximum)
Sleep mode current: 50 nA (typical), 100 nA (maximum)
Average supply current (1 measurement/second)
300 nA: RH% only (11 bit)
550 nA: RH% (11 bit) + temperature (11 bit)

Temperature range:
Operating: –40°C to 85°C
Functional: –40°C to 125°C
Supply voltage range: 1.62 V to 3.6 V

Parts Required

Name	Link
NUCLEO-L496ZG	1/PCS LOT NUCLEO-L496ZG Nucleo development board STM32L4 series development board
HDC2080	HDC2080 Temperature and Humidity Low Power Digital I2C Sensor
Connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Schematic/Connection

This is a 3.3v rated sensor even though the pin says Vcc

Nucleo	Sensor
3v3	Vcc
Gnd	Gnd
I2C1_SDA	SDA
I2C1_SCL	SCL

Code Example

I used the library from https://github.com/tinkeringtech/HDC2080_breakout

This is the default example with a few cosmetic changes

#include <HDC2080.h>

#define ADDR 0x40
HDC2080 sensor(ADDR);

float temperature = 0, humidity = 0;

void setup() {

  Serial.begin(9600);
  Serial.println("TinkeringTech HDC2080 Test");

  // Initialize I2C communication
  sensor.begin();
    
  // Begin with a device reset
  sensor.reset();
  
  // Set up the comfort zone
  sensor.setHighTemp(48);         // High temperature of 28C
  sensor.setLowTemp(2);          // Low temperature of 22C
  sensor.setHighHumidity(95);     // High humidity of 55%
  sensor.setLowHumidity(10);      // Low humidity of 40%
  
  // Configure Measurements
  sensor.setMeasurementMode(TEMP_AND_HUMID);  // Set measurements to temperature and humidity
  sensor.setRate(ONE_HZ);                     // Set measurement frequency to 1 Hz
  sensor.setTempRes(FOURTEEN_BIT);
  sensor.setHumidRes(FOURTEEN_BIT);
  
  //begin measuring
  sensor.triggerMeasurement();
}

void loop() {

  Serial.print("Temperature (C): "); 
  Serial.print(sensor.readTemp());
  Serial.print("\t\tHumidity (%): "); 
  Serial.println(sensor.readHumidity());
  
  // Wait 1 second for the next reading
  delay(2000);
  
}

Output

Open the serial monitor and you should see something like this

Temperature (C): 22.84 Humidity (%): 44.44
Temperature (C): 22.84 Humidity (%): 44.46
Temperature (C): 22.84 Humidity (%): 44.43
Temperature (C): 22.85 Humidity (%): 44.44
Temperature (C): 22.85 Humidity (%): 44.46

I do get some erratic readings at times, values like the following. I haven’t investigated this fully – I did try and increase and decrease the delay between readings with no luck.

Temperature (C): -40.00 Humidity (%): 0.00

Links

https://www.ti.com/lit/gpn/hdc2080

29th May 2020 0 comment

Code

STM32 Nucleo and LPS25H pressure sensor example using the Arduino IDE

by shedboy71 12th May 2020

written by shedboy71

In this article we look at a LPS25H pressure sensor and we will use an STM32 Nucleo and will look at an example of using this sensor with the Arduino IDE

Lets look at the sensor

The LPS25H is an ultra-compact absolute piezoresistive pressure sensor. It includes a monolithic sensing element and an IC interface able to take the information from the sensing element and to provide a digital signal to the external world.

The sensing element consists of a suspended membrane realized inside a single mono-silicon substrate. It is capable of detecting pressure and is manufactured using a dedicated process developed by ST.
The membrane is very small compared to the traditionally built silicon micromachined membranes. Membrane breakage is prevented by an intrinsic mechanical stopper.
The IC interface is manufactured using a standard CMOS process that allows a high level of integration to design a dedicated circuit which is trimmed to better match the sensing element characteristics.
The LPS25H is available in a cavity holed LGA package (HLGA). It is guaranteed to operate over a temperature range extending from -30 °C to +105 °C. The package is holed to allow external pressure to reach the sensing element.

Features

260 to 1260 mbar absolute pressure range
High-resolution mode: 1 Pa RMS
Low power consumption
Low-resolution mode: 4 μA
High-resolution mode: 25 μA
High overpressure capability: 20x full scale
Embedded temperature compensation
Embedded 24-bit ADC
Selectable ODR from 1 Hz to 25 Hz
SPI and I²C interfaces
Supply voltage: 1.7 to 3.6 V
High shock survivability: 10,000 g

Parts Required

Name	Link
NUCLEO-L496ZG	1/PCS LOT NUCLEO-L496ZG Nucleo development board STM32L4 series development board
LPS25H	Diybigworld LPS25HTR ST CJMCU-25 Miniature high Precision Pressure Sensor Temperature Compensation
Connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Schematic/Connection

Nucleo	Sensor
3v3	Vcc
Gnd	Gnd
I2C1_SCL	SCL
I2C1_SDA	SDA

Code Example

This uses the library from https://github.com/pololu/lps-arduino

#include <Wire.h>
#include <LPS.h>

LPS ps;

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

if (!ps.init())
{
Serial.println("Failed to autodetect pressure sensor!");
while (1);
}

ps.enableDefault();
}

void loop()
{
float pressure = ps.readPressureMillibars();
float altitude = ps.pressureToAltitudeMeters(pressure);
float temperature = ps.readTemperatureC();

Serial.print("p: ");
Serial.print(pressure);
Serial.print(" mbar\ta: ");
Serial.print(altitude);
Serial.print(" m\tt: ");
Serial.print(temperature);
Serial.println(" deg C");

delay(1000);
}

Output

Open the serial monitor and you should see something like this

p: 954.97 mbar a: 496.80 m t: 24.23 deg C
p: 954.99 mbar a: 496.62 m t: 24.20 deg C
p: 954.93 mbar a: 497.17 m t: 24.18 deg C
p: 954.94 mbar a: 497.08 m t: 24.14 deg C
p: 954.95 mbar a: 497.01 m t: 24.11 deg C

Links

https://www.st.com/resource/en/datasheet/lps25h.pdf

12th May 2020 0 comment

Code

STM32 Nucleo and LPS22HB absolute pressure sensor example using the Arduino IDE

by shedboy71 29th April 2020

written by shedboy71

In this article we look at another absolute pressure sensor – this time its the LPS22HB and once again we will connect this to a STM32 nucleo

The LPS22HB is an ultra-compact piezoresistive absolute pressure sensor which functions as a digital output barometer. The device comprises a sensing element and an IC interface which communicates through I²C or SPI from the sensing element to the application.

The sensing element, which detects absolute pressure, consists of a suspended membrane manufactured using a dedicated process developed by ST.
The LPS22HB is available in a full-mold, holed LGA package (HLGA). It is guaranteed to operate over a temperature range extending from -40 °C to +85 °C. The package is holed to allow external pressure to reach the sensing element.

Features

260 to 1260 hPa absolute pressure range
Current consumption down to 3 μA
High overpressure capability: 20x full-scale
Embedded temperature compensation
24-bit pressure data output
16-bit temperature data output
ODR from 1 Hz to 75 Hz

SPI and I²C interfaces
Embedded FIFO
Interrupt functions: Data Ready, FIFO flags, pressure thresholds
Supply voltage: 1.7 to 3.6 V
High shock survivability: 22,000 g

Parts Required

Name	Link
NUCLEO-L496ZG	1/PCS LOT NUCLEO-L496ZG Nucleo development board STM32L4 series development board
LPS22HB	Semoic Lps22Hb Pressure Resistance Pressure Sensor Module for High Intensity Industrial Control
Connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Schematic/Connection

I used 3v3, there is a Vin pin and I could have quite easily used 5v

Nucleo	Sensor
3v3	3v3
Gnd	Gnd
I2C1_SCL	SCL
I2C1_SDA	SDA

Code Example

This uses the library from hhttps://github.com/adrien3d/IO_LPS22HB

/***************************************************************************
This is a library for the LPS22HB Absolute Digital Barometer

Designed to work with all kinds of LPS22HB Breakout Boards

These sensors use I2C, 2 pins are required to interface, as this :
VDD to 3.3V DC
SCL to A5
SDA to A4
GND to common groud

Written by Adrien Chapelet for IoThings
***************************************************************************/

#include <Wire.h>

#include "IO_LPS22HB.h"

IO_LPS22HB lps22hb;

void setup()
{
Serial.begin(9600);
Serial.println("IoThings LPS22HB Arduino Test");

lps22hb.begin(0x5D);

byte who_am_i = lps22hb.whoAmI();
Serial.print("Who Am I? 0x");
Serial.print(who_am_i, HEX);
Serial.println(" (expected: 0xB1)");
if (who_am_i != LPS22HB_WHO_AM_I_VALUE) {
Serial.println("Error while retrieving WHO_AM_I byte...");
while (true) {
// loop forever
}
}
}

void loop()
{
Serial.print("P=");
Serial.print(lps22hb.readPressure());
Serial.print(" mbar, T=");
Serial.print(lps22hb.readTemperature());
Serial.println("C");
delay(300);
}

Output

Open the serial monitor and you should see something like this

IoThings LPS22HB Arduino Test
Who Am I? 0xB1 (expected: 0xB1)
P=954.86 mbar, T=27.43C
P=954.91 mbar, T=27.40C
P=954.86 mbar, T=27.37C
P=954.88 mbar, T=27.34C
P=954.89 mbar, T=27.34C
P=954.88 mbar, T=27.33C
P=954.90 mbar, T=27.27C
P=954.87 mbar, T=27.22C

Links

https://www.st.com/resource/en/datasheet/lps22hb.pdf

29th April 2020 0 comment

Code

STM32 Nucleo and SHTC1 digital humidity sensor example using the Arduino IDE

by shedboy71 12th April 2020

written by shedboy71

In this article we look at an SHTC1 digital humidity sensor and we will connect it to a Nucleo

Lets look at some information about the sensor

The SHTC1 is a digital humidity sensor designed especially for high-volume consumer electronics applications. This humidity sensor is strictly designed to overcome conventional limits for size, power consumption, and price-performance ratio, in order to fulfill the current and future requirements of the consumer electronics market.

Sensirion’s CMOSens® technology offers a complete sensor system on a single chip, consisting of a capacitive humidity sensor, a band-gap temperature sensor, analog and digital signal processing, A/D converter, calibration data memory, and a digital communication interface supporting I²C fast mode. The ultra-small, 2 × 2 × 0.75 mm³ DFN package enables applications to be placed in even the most limited of spaces. The sensor covers a humidity measurement range of 0 to 100 %RH and a temperature measurement range of –30°C to 100°C with a typical accuracy of ±3 %RH and ±0.3°C.

The operating voltage of 1.8 V and an energy budget below 1 µJ per measurement make the SHTC1 suitable for mobile or wireless applications running on the lowest power budgets. With the industry-proven quality and reliability of Sensirion’s humidity sensors and constant accuracy over a large measurement range, the SHTC1 humidity sensor offers an unprecedented price-performance ratio. Tape and reel packaging together with suitability for standard SMD assembly processes make the SHTC1 predestined for high-volume applications.

Features

Interface	I²C
Supply voltage	1.8 V
Power consumption	2µW (at 1 reading per second in low power mode)
Measuring range (RH)	0 – 100% relative humidity
Measuring range (T)	-30 to +100°C (-22 to +212°F)
Response time (RH)	8s (tau63%)

Parts Required

Name	Link
NUCLEO-L496ZG	1/PCS LOT NUCLEO-L496ZG Nucleo development board STM32L4 series development board
SHTC1	CJMCU-189 SHTC1 Digital Temperature and Humidity Humidity Temperature Sensor I2C Communication
Connecting wire	Free shipping Dupont line 120pcs 20cm male to male + male to female and female to female jumper wire

Schematic/Connection

Nucleo	Sensor
3v3	Vcc
Gnd	Gnd
I2C1_SDA	SDA
I2C1_SCL	SCL

Code Example

This uses the library from https://github.com/Sensirion/arduino-sht

[codesyntax lang=”cpp”]

#include <Wire.h>

#include “SHTSensor.h”

SHTSensor sht;
// To use a specific sensor instead of probing the bus use this command:
// SHTSensor sht(SHTSensor::SHT3X);

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

Wire.begin();
Serial.begin(9600);
delay(1000); // let serial console settle

if (sht.init()) {
Serial.print(“init(): success\n”);
} else {
Serial.print(“init(): failed\n”);
}
sht.setAccuracy(SHTSensor::SHT_ACCURACY_MEDIUM); // only supported by SHT3x

}

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

if (sht.readSample()) {
Serial.print(“SHT:\n”);
Serial.print(” RH: “);
Serial.print(sht.getHumidity(), 2);
Serial.print(“\n”);
Serial.print(” T: “);
Serial.print(sht.getTemperature(), 2);
Serial.print(“\n”);
} else {
Serial.print(“Error in readSample()\n”);
}

delay(1000);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this

init(): success
SHT:
RH: 42.01
T: 23.05
SHT:
RH: 42.04
T: 23.02
SHT:
RH: 42.06
T: 23.02

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

Hardware

RobotDyn SAMD21 M0 arduino compatible board

by shedboy71 19th October 2017

written by shedboy71

I’ve wanted either than an Arduino Zero or M0 for a while then i saw this board as I was browsing an online store, coming in at under $14 it seemed reasonably priced for an arduino type board with an ARM Cortex M0 microcontroller. Since it can be used with the ARduino IDE and potentially can use shields as well this seems a good option for beginners and hobbyists

Lets look at a bit of the blurb on the board

The RobotDyn SAMD21 M0 represents a powerful, 32-bit extension of the Arduino UNO platform. The board is powered by Atmel’s SAMD21 MCU, featuring a 32-bit ARM Cortex® M0 core.
Compatible with Arduino Zero and Arduino M0.

SAMD21 M0

The SAMD21 M0 board expands the family by providing increased performance, enabling a variety of project opportunities for devices, and acts as a great educational tool for learning about 32-bit application development.
The Zero applications span from smart IoT devices, wearable technology, high-tech automation, to crazy robotics. The board is powered by Atmel’s SAMD21 MCU, which features a 32-bit ARM Cortex® M0+ core. One of its most important features is Atmel’s Embedded Debugger (EDBG), which provides a full debug interface without the need for additional hardware, significantly increasing the ease-of-use for software debugging. EDBG also supports a virtual COM port that can be used for device and bootloader programming.

Features

Model Number:SAMD21-M0
Microcontroller:ATSAMD21G18, 48pins LQFP
Operating Voltage:3.3V
Clock Speed:48 MHz
Input Voltage:6-24V, USB 5V (recommended 7-9V)
Vout:3.3V/800mA
Digital I/O Pins:20
PWM Pins:All but pins 2 and 7
Analog In Pins:6, 12-bit ADC channels
Analog Out Pins:1, 10-bit DAC

Key thing in the specs is that the board I/O pins are rated at 3.3v, so take that into consideration.

You need to add support for this board via the Boards manager

This core is available as a package in the Arduino IDE cores manager. Just open the “Boards Manager” and install the package called:

“Arduino SAMD Boards (32-bit ARM Cortex-M0+)”

the RobotDyn is basically an Arduino/ Genuino M0 clone board (just cheaper)

Code

The standard blink sketch works for testing – you need to select your board as an Arduino M0 in the boards manager

[codesyntax lang=”cpp”]

// the setup function runs once when you press reset or power the board
void setup() {
  // initialize digital pin LED_BUILTIN as an output.
  pinMode(LED_BUILTIN, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
  digitalWrite(LED_BUILTIN, HIGH);   // turn the LED on (HIGH is the voltage level)
  delay(1000);                       // wait for a second
  digitalWrite(LED_BUILTIN, LOW);    // turn the LED off by making the voltage LOW
  delay(1000);                       // wait for a second
}

[/codesyntax]

Links

http://robotdyn.com/catalog/boards/samd21_m0/

SAMD21 M0. 32-bit ARM Cortex M0 core. Compatible with Arduino Zero, Arduino M0. Form R3.

19th October 2017 0 comment

Arduino Due

Arduino Due and SHT31 temperature and humidity sensor example

by shedboy71 24th June 2017

written by shedboy71

SHT31 is the next generation of Sensirion’s temperature and humidity sensors. It builds on a new CMOSens® sensor chip that is at the heart of Sensirion’s new humidity and temperature platform.

The SHT3x-DIS has increased intelligence, reliability and improved accuracy specifications compared to its predecessor. Its functionality includes enhanced signal processing, two distinctive and user selectable I2C addresses and communication speeds of up to 1 MHz. The DFN package has a footprint of 2.5 x 2.5 mm2 while keeping a height of 0.9 mm.

This allows for integration of the SHT3x-DIS into a great variety of applications.

Features

Fully calibrated, linearized, and temperature compensated digital output
Wide supply voltage range, from 2.4 V to 5.5 V
I2C Interface with communication speeds up to 1 MHz and two user selectable addresses

If you’re using an Arduino simply connect the VIN pin to the 3v3 voltage pin, GND to ground, SCL to I2C Clock (21) and SDA to I2C Data (20).

Layout

Code

This example uses the adafruit sht31 library – https://github.com/adafruit/Adafruit_SHT31

[codesyntax lang=”cpp”]

#include <Arduino.h>
#include <Wire.h>
#include "Adafruit_SHT31.h"

Adafruit_SHT31 sht31 = Adafruit_SHT31();


void setup() 
{
  Serial.begin(9600);
  if (! sht31.begin(0x44)) 
  {
    Serial.println("Couldn't find SHT31");
    while (1) delay(1);
  }
}


void loop() 
{
  float t = sht31.readTemperature();
  float h = sht31.readHumidity();

  if (! isnan(t)) 
  {
    Serial.print("Temp *C = "); Serial.println(t);
  } 
  else 
  { 
    Serial.println("Failed to read temperature");
  }
  
  if (! isnan(h)) 
  {
    Serial.print("Hum. % = "); Serial.println(h);
  } 
  else 
  { 
    Serial.println("Failed to read humidity");
  }
  Serial.println();
  delay(1000);
}

[/codesyntax]

Link
Free shipping SHT31 Temperature & SHT31-D Humidity Sensor module Breakout

24th June 2017 0 comment

Arduino Due

Arduino Due and HTU21 sensor example

by shedboy71 24th June 2017

written by shedboy71

The HTU21D(F) is a new digital humidity sensor with temperature output by MEAS. Setting new standards in terms of size and intelligence, it is embedded in a reflow solderable Dual Flat No leads (DFN) package with a small 3 x 3 x 0.9 mm footprint. This sensor provides calibrated, linearized signals in digital, I²C format. HTU21D(F) digital humidity sensors are dedicated humidity and temperature plug and play transducers for OEM applications where reliable and accurate measurements are needed. Direct interface with a micro-controller is made possible with the module for humidity and temperature digital outputs. These low power sensors are designed for high volume and cost sensitive applications with tight space constraints.

Every sensor is individually calibrated and tested. Lot identification is printed on the sensor and an electronic identification code is stored on the chip – which can be read out by command. Low battery can be detected and a checksum improves communication reliability.

Schematic

Code

This example uses the https://github.com/adafruit/Adafruit_HTU21DF_Library

[codesyntax lang=”cpp”]

#include <Wire.h>
#include "Adafruit_HTU21DF.h"

// Connect Vin to 3-5VDC
// Connect GND to ground
// Connect SCL to I2C clock pin (A5 on UNO)
// Connect SDA to I2C data pin (A4 on UNO)

Adafruit_HTU21DF htu = Adafruit_HTU21DF();

void setup() {
  Serial.begin(9600);
  Serial.println("HTU21D-F test");

  if (!htu.begin()) {
    Serial.println("Couldn't find sensor!");
    while (1);
  }
}


void loop() {
  Serial.print("Temp: ");
  Serial.print(htu.readTemperature());
  Serial.print("\t\tHum: ");
  Serial.println(htu.readHumidity());
  delay(500);
}

[/codesyntax]

Links

Humidity Sensor – HTU21 Breakout Board GY-21

24th June 2017 0 comment

Arduino Due

Arduino Due and HDC1008 example

by shedboy71 24th June 2017

written by shedboy71

The HDC1000 is a digital humidity sensor with integrated temperature sensor that provides excellent measurement accuracy at very low power. The device measures humidity based on a novel capacitive sensor. The humidity and temperature sensors are factory calibrated.

The sensing element of the HDC1000 is placed on the bottom part of the device, which makes the HDC1000 more robust against dirt, dust, and other environmental contaminants. The HDC1000 is functional within the full –40°C to +125°C temperature range.

Key Features

Relative Humidity (RH) Operating Range 0% to 100%
14 Bit Measurement Resolution
Relative Humidity Accuracy ±3%
Temperature Accuracy ±0.2°C
Supply Voltage 3 V to 5 V
I2C Interface

Schematic

Code

[codesyntax lang=”cpp”]

#include<Wire.h>

// HDC1008 I2C address is 0x40(64)
#define hdcAddr 0x40

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

  // Starts I2C communication
  Wire.beginTransmission(hdcAddr);
  // Select configuration register
  Wire.write(0x02);
  // Temperature, humidity enabled, resolultion = 14-bits, heater on
  Wire.write(0x30);
  // Stop I2C Transmission
  Wire.endTransmission();
  delay(300);
}

void loop()
{
  unsigned int data[2];

  Wire.beginTransmission(hdcAddr);
  // Send temp measurement command
  Wire.write(0x00);
  Wire.endTransmission();
  delay(500);

  // Request 2 bytes of data
  Wire.requestFrom(hdcAddr, 2);

  // Read 2 bytes of data for temperature
  if (Wire.available() == 2)
  {
    data[0] = Wire.read();
    data[1] = Wire.read();
  }

  int temp = (data[0] * 256) + data[1];
  float celsTemp = (temp / 65536.0) * 165.0 - 40;
  float fahrTemp = celsTemp * 1.8 + 32;


  Wire.beginTransmission(hdcAddr);
  // Send humidity measurement command
  Wire.write(0x01);
  Wire.endTransmission();
  delay(500);

  // Request 2 bytes of data
  Wire.requestFrom(hdcAddr, 2);
  // Read 2 bytes of data to get humidity
  if (Wire.available() == 2)
  {
    data[0] = Wire.read();
    data[1] = Wire.read();
  }

  // Convert the data
  float humidity = (data[0] * 256) + data[1];
  humidity = (humidity / 65536.0) * 100.0;

  Serial.print("Humidity : ");
  Serial.print(humidity);
  Serial.println(" %RH");
  Serial.print("Celsius : ");
  Serial.print(celsTemp);
  Serial.println(" C");
  Serial.print("Fahrenheit : ");
  Serial.print(fahrTemp);
  Serial.println(" F");
  delay(500);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this

Humidity : 43.26 %RH
Celsius : 28.07 C
Fahrenheit : 82.52 F
Humidity : 46.03 %RH
Celsius : 28.70 C
Fahrenheit : 83.67 F
Humidity : 48.71 %RH
Celsius : 29.38 C
Fahrenheit : 84.88 F
Humidity : 51.26 %RH
Celsius : 29.74 C
Fahrenheit : 85.53 F

Links
HDC1008 Digital Humidity and Temperature Sensor Breakout Board

24th June 2017 0 comment

Arduino Due

Arduino Due and HMC5983L example

by shedboy71 24th June 2017

written by shedboy71

The Honeywell HMC5983 is a temperature compensated three-axis integrated circuit magnetometer. This surface-mount, multi-chip module is designed for low-field magnetic sensing for applications such as automotive and personal navigation, vehicle detection, and pointing. The HMC5983 includes our state-of-the-art, high-resolution HMC118X series magnetoresistive sensors plus an ASIC containing amplification, automatic degaussing strap drivers, offset cancellation, and a 12-bit ADC that enables 1° to 2° compass heading accuracy.

The I²C or SPI serial bus allows for easy interface. The HMC5983 utilizes Honeywell’s Anisotropic Magnetoresistive (AMR) technology that provides advantages over other magnetic sensor technologies. Honeywell’s anisotropic, directional sensors excel in linearity, low hysteresis, null output and scale factor stability over temperature, and with very low cross-axis sensitivity. These sensors’ solid-state construction is designed to measure both the direction and the magnitude of magnetic fields, from milli-gauss to 8 gauss. Honeywell’s Magnetic Sensors are among the most sensitive and reliable low-field sensors in the industry

Here is a typical module

Schematic

The layout example shows a 5883L but the 5983L has exactly the same connection

Code

[codesyntax lang=”cpp”]

#include <Wire.h> //I2C Arduino Library
#define addr 0x1E //I2C Address for The HMC5983

void setup()
{
  Serial.begin(9600);
  Wire.begin();
  Wire.beginTransmission(addr); //start talking
  Wire.write(0x02); // Set the Register
  Wire.write(0x00); // Tell the HMC5883 to Continuously Measure
  Wire.endTransmission();
}

void loop()
{
  int x,y,z;
  //Tell the HMC what regist to begin writing data into
  Wire.beginTransmission(addr);
  Wire.write(0x03);
  Wire.endTransmission();
  //Read the data
  Wire.requestFrom(addr, 6);
  if(6<=Wire.available())
  {
    x = Wire.read()<<8; //MSB  x
    x |= Wire.read(); //LSB  x
    z = Wire.read()<<8; //MSB  z
    z |= Wire.read(); //LSB z
    y = Wire.read()<<8; //MSB y
    y |= Wire.read(); //LSB y
  }
  // Show Values
  Serial.print("X Value: ");
  Serial.println(x);
  Serial.print("Y Value: ");
  Serial.println(y);
  Serial.print("Z Value: ");
  Serial.println(z);
  Serial.println();
  delay(500);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this

X Value: 65463
Y Value: 65436
Z Value: 101

X Value: 38
Y Value: 65407
Z Value: 89

X Value: 65509
Y Value: 65455
Z Value: 135

X Value: 65459
Y Value: 4
Z Value: 106

X Value: 65427
Y Value: 65496
Z Value: 94

Links
GY-282 HMC5983 Replace HMC5883L High-precision High-sensitivity Temperature Compensation Triaxial Compass IIC SPI Module

24th June 2017 0 comment

Arduino Due

Arduino Due and BMP085 example

by shedboy71 24th June 2017

written by shedboy71

In this example we connect a BMp085 sensor to an Arduino Due, you can use this to measure barometric pressure and temperature

This sensor has been replaced by some newer versions but there are still many modules available so here is an example on how to use it

Schematics

Easy to connect up, you can see this in the layout below.

Code

I downloaded the library from https://github.com/adafruit/Adafruit-BMP085-Library and installed it

[codesyntax lang=”cpp”]

#include <Wire.h>
#include <Adafruit_BMP085.h>

Adafruit_BMP085 bmp;

void setup()
{
Serial.begin(9600);
if (!bmp.begin())
{
Serial.println("Could not find a BMP085 sensor!");
while (1) {}
}
}

void loop()
{
Serial.print("Temperature = ");
Serial.print(bmp.readTemperature());
Serial.println(" *C");

Serial.print("Pressure = ");
Serial.print(bmp.readPressure());
Serial.println(" Pa");

Serial.print("Altitude = ");
Serial.print(bmp.readAltitude());
Serial.println(" meters");

Serial.print("Real altitude = ");
Serial.print(bmp.readAltitude(101500));
Serial.println(" meters");

Serial.println();
delay(500);
}

[/codesyntax]

Output

Open the serial monitor and you should see something like this

Temperature = 27.30 *C
Pressure = 99058 Pa
Altitude = 190.05 meters
Real altitude = 204.46 meters

Temperature = 27.60 *C
Pressure = 99064 Pa
Altitude = 189.63 meters
Real altitude = 204.29 meters

Temperature = 27.90 *C
Pressure = 99062 Pa
Altitude = 189.54 meters
Real altitude = 203.78 meters

24th June 2017 0 comment

Hardware

STM32 development board and Arduino

by shedboy71 3rd February 2016

written by shedboy71

Being a sucker for a bargain and wanting to get into basic ARM development I’ve bought a couple of STM32 boards in the past, these tend to be low cost and one of the variants is below. Basically this is just the STM32 chip with breakout connectors attached. For ease of use I noticed that you can use the Arduino IDE to develop and upload simple test projects, probably not what the purists would like to see but for me a gentle introduction

The trouble with these low cost breakout boards is that the documentation is non existent but luckily some kind hearted people have been through the pain, here are some useful links. Here is the first one, it is commonly called – STM32 Minimum System Development Board for Arduino. Why Arduino, who knows other than trying to cash in on the popularity, it is possible as we will try and explain to add support to the Arduino IDE but this is never documented with the boards.

STM32Mini-annotated

I recommend you following the instructions at – http://www.rogerclark.net/stm32f103-and-maple-maple-mini-with-arduino-1-5-x-ide/

Newer Arduino IDE versions will need to do the following – http://www.rogerclark.net/work-around-for-arduino-stm32-with-ide-v-1-6-3-or-newer/ , basically you need to go to the Board Manager and install support for the ARduino Due.

Connection –

I connected a Prolific PL2303 USB-to-Serial port adapter to my STM32 like this. AN FTDI or Cp2102 are other common options, as long as there is a usable COM port it shouldn’t make a difference

usb-ttl1

3.3v – Any 3.3v on the board – usually marked 3.3
TX – A10
RX – A9
Gnd – Any Gnd on the board , I used the SWD one. Usually marked up as G on the board
Now at first I recieved an error message – Got NACK from device on command 0x43. Looking at the post at http://www.stm32duino.com/viewtopic.php?f=20&t=747&sid=cd8271c9e0bb7f11cb9c230520a67697&start=10 , I followed the steps below as mentioned in one of the posts

It sounds like the chip has been locked, and will need to be fully erased and unlocked before you can do anything

Try downloading STM’s “Flash loader demonstrator” (its not really a demonstrator its the flash uploader via serial)
http://www.st.com/web/en/catalog/tools/PF257525

This removed the issue for me, this is the code you will need for a simple example, the board mentioned earlier has an LED connected to PC13 we will flash this on and off
Code

[codesyntax lang=”cpp”]

// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin PC13 as an output.
pinMode(PC13, OUTPUT);
}

// the loop function runs over and over again forever
void loop() {
digitalWrite(PC13, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(PC13, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second
}

[/codesyntax]

Click on the reset button of the board and upload the sketch via the IDE, in the preferences of the IDE I check Verbose warning. Here is what i saw on a good upload, you should see something similar

[codesyntax lang=”dos”]

http://stm32flash.googlecode.com/

Using Parser : Raw BINARY
Interface serial_w32: 230400 8E1
Version : 0x22
Option 1 : 0x00
Option 2 : 0x00
Device ID : 0x0410 (Medium-density)
- RAM : 20KiB (512b reserved by bootloader)
- Flash : 128KiB (sector size: 4x1024)
- Option RAM : 16b
- System RAM : 2KiB
Write to memory
Erasing memory

Wrote address 0x08000100 (3.91%) 
Wrote address 0x08000200 (7.82%) 
Wrote address 0x08000300 (11.73%) 
Wrote address 0x08000400 (15.64%) 
Wrote address 0x08000500 (19.55%) 
Wrote address 0x08000600 (23.46%) 
Wrote address 0x08000700 (27.37%) 
Wrote address 0x08000800 (31.28%) 
Wrote address 0x08000900 (35.19%) 
Wrote address 0x08000a00 (39.10%) 
Wrote address 0x08000b00 (43.01%) 
Wrote address 0x08000c00 (46.92%) 
Wrote address 0x08000d00 (50.82%) 
Wrote address 0x08000e00 (54.73%) 
Wrote address 0x08000f00 (58.64%) 
Wrote address 0x08001000 (62.55%) 
Wrote address 0x08001100 (66.46%) 
Wrote address 0x08001200 (70.37%) 
Wrote address 0x08001300 (74.28%) 
Wrote address 0x08001400 (78.19%) 
Wrote address 0x08001500 (82.10%) 
Wrote address 0x08001600 (86.01%) 
Wrote address 0x08001700 (89.92%) 
Wrote address 0x08001800 (93.83%) 
Wrote address 0x08001900 (97.74%) 
Wrote address 0x08001994 (100.00%) Done.

Starting execution at address 0x08000000... done.

[/codesyntax]

Overall its a nice low cost board, like a lot of these Chinese type electronic development boards and kits if you can get over the initial challenge of actually getting the board to do anything then its quite useful, its been a while since I got so excites at a simple LED flashing example.

Links
1pcs STM32F103C8T6 ARM STM32 Minimum System Development Board Module For arduino

3rd February 2016 0 comment