Category: Electronics

Temperature and Humidity Sensor

Posted on | by andrewlai61616

This is a homework in class where we are assigned to utilize the temperature and humidity sensor DHT11 and an LCD display. Once activated, the LCD display will show either the temperature or the humidity being detected by the sensor. A button can be pressed to switch between temperature and humidity display.

Complex functionality can be achieved by including pre-coded libraries for controlling these components using Arduino, the development board I had used.

Though being a very simple project, such components serve as the simple building block for constructing a sophisticated hardware system. Therefore, this project plays an important role in the initial stage of hardware design for me.

Here’s a simple control process demonstration:

Logic Circuit Control for Number Display

Posted on | by andrewlai61616

Most people believe, including me, that programming is a powerful technique, and a lot of things in everyday life are realized by programming. However, being taken away this skill, what can still be achieved?

In this project, a logic circuit with complex functionality is built using only simple IC chips and circuitry. A 7-segment LED displays numeral from 0 to 9 with adjustable frequency using a potentiometer, and the number can be reset anytime to 0 by pressing a reset button. For programmers utilizing a simple development board such as Arduino, this seems like a piece of cake. However, it requires a certain degree of knowledge for digital circuit and IC chip control in order to accomplish it without coding.

Here, two simple IC chips are used: a 4024 counter and a 4511 BCD to 7-segment converter. An oscillator circuit with square wave output and potentiometer-controllable frequency is constructed, and the signal is fed into the 4024 counter, which outputs bitwise data to the 4511 converter, and eventually sends to the 7-segment display. A latch circuit and button is connected to the reset input of the 4024 counter for adding the reset function.

I was fascinated by the wide applicability of digital circuits, which can achieve low-cost and stable hardware features such as this project.

Here’s a video demonstration of this project (note that the Arduino on the left is just for power supply):