002 - Brickcell DHT11 | MakeCode Microbit

Introduction

The DHT11 is a low-cost, digital temperature and humidity sensor. It is commonly used in electronics projects and application to measure temperature and relative humidity. The sensor is consists of a capacitive humidity seensor and a thermistor to measure temperature. It provides digital output, making it relatively easy to interface with microcontrollers like microbit.

Temperature Range

The DHT11 can measure temperatures in the range of 0 degree Celsius to 50 degrees Celsius with accuracy of +/-2 degrees Celsius.

Humidity Range

The DHT11 can measure humidity in the range of 20% to 90% with a +/-5% accuracy.

Interface

The DHT11 communicates with the microcontr4oller using a single-wire (1-wire) communication protocol, which involves sending and receiving data via a single data pin.

Hardware Instruction

Let's explore how to connect the DHT11 Temperature and Humidity sensor to a micro:bit microcontroller and utilize MakeCode for programming.

1. Connect the DHT11 sensor GND pin to microbit GND pin.
2. Connect the DHT11 sensor VCC pin to microbit VCC pin.
3. Connect the DHT11 sensor signal (S) pin to microbit pin 0.

Software Instruction

Now, let's start into programming the micro:bit to utilize the NTC temperature sensor.

1. Login to https://makecode.microbit.org/ using your Microsoft account.
2. Create a new project by clicking the "New Project" button. You may name it anything you want, I suggest to name it with descriptive name such as "temperature-dht11-test".
3. Click the "Extensions" block just under the "Math" block.
4. Type https://github.com/gbantique/brickcell-temperature-dht11/ on the search bar.
5. Select the "brickcell-temperature-dht11" from the search results. The "temperature dht11" block should appear under the "Brickcell" block.
6. Copy the code provided below.

1serial.setBaudRate(BaudRate.BaudRate115200)
2
3basic.forever(function () {
4    serial.writeLine("" + (Brickcell.readDHT(dataType.temperature, DigitalPin.P0)))
5    basic.pause(2000)
6})

7. Open a Serial Monitor such as Termite terminal app https://www.compuphase.com/software_termite.htm/. Set the baud rate to 115200 bps.

Or you make a copy of my created project in your MakeCode workspace.

https://makecode.microbit.org/S97457-22215-78353-20278/

Expected Result

If you carefully follow the provided instruction above, you should be able to view the measured temperature/humidity on the serial terminal every 2000 milliseconds.