Author : richzha

It is very common to use human body detecting sensors – the infrared sensors in indoor security applications. The principle is that the detection element will detect the infrared radiation of the human body, and convert it into a weak voltage signal, which is amplified and output. In order to improve the detection sensitivity of […]

Temperature and humidity are also very common indicators in our daily lives, and I used the DHT11 digital temperature and humidity sensors on my Raspberry Pi. This is the wiring diagram of the DHT11 on the PiHAT, and we can see that the DHT11 is connected to pin 19 of the Raspberry PI, which can […]

DS18B20 is a commonly used digital temperature sensor, its output is a digital signal, small size, strong anti-interference ability, and high precision. It can measures temperatures from -55°C to +125°C (-67°F to +257°F) with an accuracy of ±0.5°C GND: Ground DQ: Data input and output VDD: Digital power supply The Raspberry PI is connected to […]

Raspberry PI has many models, memory and their own SD card capacity is not the same, so we can create a Raspberry PI system display system, the Raspberry PI CPU temperature, CPU usage, memory, hard disk (SD card) capacity and IP address information through OLED display, especially IP address, In this way, we can know […]

This time I decided to make a timer that does the same job as the one we use on our phone or a stopwatch. As we all know, we can press two buttons: one controls the start and stop of the count, and the other resets the timer. I’ve split it into two parts, firstly […]

Now that I can use OLED to display text, I have an idea for an electronic clock. I can get real-time time data by calling the time library, and then print the hours, minutes and seconds on the OLED. The DateTime library is needed, it allows me to get information about dates and times. Here […]

In my previous two blogs, I learned about using ADC to detect the voltage across a variable resistor and using OLED to display some messages. So, I came up with the idea of displaying the detected voltage using the OLED. Flow Chart: The process is very similar to the previous one, the only difference is […]

OLED short for Organic Light-Emitting Diode – a technology that uses LEDs in which the light is produced by organic molecules. It is a solid-state device consisting of a thin, carbon-based semiconductor layer that emits light when electricity is applied by adjacent electrodes. The characteristic of OLED is that it can emit light by itself, so […]

The function of the ADC is to convert analogue signals into digital signals. Since computers can ultimately only recognise binary numbers, external analogue signals are often converted by the ADC into digital information that it can recognise. In Raspberry PI, a common application is to convert a changing voltage into a digital signal. Raspberry Pi […]

In my last work, the buzzer stayed on continuously, which was not in line with the real situation, so this time I want to change the buzzer’s sounding pattern so that the buzzer’s sounding frequency is synchronised with the frequency of the LED blinking. Main Code: The main idea of this code is to use […]