Week 11

This week I decided to make a device that will read the information from the temperature and humidity sensor. Almost a room weather station.

I chose DHT11 as the sensor, as it is a very common and cheap option.

Here is datasheet for this sensor: https://www.mouser.com/datasheet/2/758/DHT11-Technical-Data-Sheet-Translated-Version-1143054.pdf

I will use the Attiny45 microcontroller, read the data from the sensor to one of its pins, and then transfer the data through the serial interface to the computer

I chose the Eagle for my electronics design because it allows me to adjust the design rules more conveniently than Kicad.

It’s pretty simple, I used standard components from the “fab” library. I didn’t find a component for the DHT11 sensor, so I chose another one with the same size of pads

The PB4 pin of the microcontroller is used to read data from the sensor

The SCK pin is used for data transfer via the serial interface

When I was programming the board, I had an error “avrdude: verification error, first mismatch at byte 0x0000”. I started looking for the reason and realized that I needed a 100nF capacitor between Vcc and GND and a 10KΩ resistor between RESET and Vcc. After that everything went well.