For our project we decided to make a digital thermometer and humidity sensor. The project takes readings from the surrounding air using a HDC1050 sensor and outputs the temperature and humidity in alternating turns after a wait time of 4 seconds. We figured it would be a beneficial project to do as the temperature is commonly sought after information, and a humidity reading is useful for determining personal comfort.
| Temperature | Humidity | |
| Final design (front) | Final design (back) | |
In the project, we used a 32 Bit Cypress Semiconductor Corp PSoC 4100 (CY8C4125PVI-482) chip which uses an ARM Cortex-M0 as its core processor. This microprocessor was a great platform to implement the I2C protocol with the sensor. The sensor we used is the Texas Instruments HDC1050, which is a low power/high accuracy digital humidity and temperature sensor. For relative humidity this sensor is accurate to within 3%, 0.2°C for temperature and only uses 1.3µA for each relative humidity and temperature measurement.
| Schematic | Assembly | |
To output the data to a user the device uses a 4 character, 7 segment standard LCD screen made by Varitronix. It is a directional LCD so it is better viewed from below or straight on. The low power design of the project allows it to be powered by two standard AAA batteries.
The programming of this thermometer done on the PSoC software creator. It starts by starting/initializing each hardware component, and configuring the timer. The program then continues into a loop that will display the temperature or humidity every 4 seconds. Once the timer has reached 4 seconds, it will wake up the sensor and will request a new reading, and will display the result. If the temperature is to be displayed, the reading from the sensor first needs to be configured to Fahrenheit, and the right-most segment on the LCD is configured to display an 'F' (for Fahrenheit). After another 4 seconds, the sensor will be awakened again and will take a new reading, and the humidity will be displayed on the LCD screen. The right-most segment of the LCD is configured to display an 'H' during that time period (for humidity).
This project was challenging, but the PSoC software has a lot of resources to help the process. We highly recommend to watch all of the training videos that they provide on their website. We are happy with the outcome, and it is fun to watch a thermometer that we created ourselves.
Last modified:Mon, Jan 23, 2023.