Articles

Air conditioners consume a fair amount of electricity. As such, forgetting to turn one off before leaving one's home can result in an expensive electricity bill. This is a Wi-Fi enabled controller for air condtioners, which can turn the unit on or off according to MQTT messages. It is built around an Wemos D1 mini and interfaces with the AC using an IR LED.

This is an IoT ceiling light controller which includes an HC-SR501 PIR motion sensor. It is built around a Wemos D1 mini (ESP8266 breakout board), which controls a homemade TRIAC breakout board. TRIACs provide the advantage of switching devices on and off silently, as opposed to a mechanical relay.

I wanted my home automation system to detect when I arrive home so as to unlock my door automatically or let me know if I leave the apartment without turning the A/C off. I figured my smartphone could be used to achieve this since it is equipped with a vast array of sensors and connectivity options. For example, I could use an app like OwnTracks which would send an MQTT message once I enter a certain perimeter around my apartment. However, constantly monitoring one's GPS location is wasteful in terms of battery life. Another option would be to ping my phone's IP address to check if it is connected to the WiFi, but smartphones can sometimes take a while to connect. So, I decided to use BLE advertising, which does not use too much battery while still remaining constantly active.

Dogs are great at detering burglars from entering one's home. This system brings the same advantage, without the need for an actual dog.

When learning a new language, there is no way around having to learn its vocabulary. This simple web app was made to help with this process by providing a multiple choice question style UI. It was designed mainly for Japanese, which uses Chinese characters that can have multiple readings.

Few would argue that having lights turned on in a room without occupant is a waste of electricity. Ideally, lights and other appliances like air conditioners would only be turned on when someone is around. This project is a NodeJS application that gathers data about the occupancy of an apartment and manages appliances accordingly.

This project consists of an HC-SR501 PIR motion sensor and a DHT22 temperature and humidity sensor connected to a Wemos D1 mini, an ESP8266 breakout board.

One of the companies I used to work for had a serious bathroom issue: My floor had only three toilet stalls for about 200 employees. There were countless times when I would walk all the way to the bathroom only to find all stalls occupied. I built this simple system to quickly identify whether one or more stall were. It consists of an IoT sensor installed on the bathroom stalls' door and an indicator placed somewhere easily visible.

One of the companies I worked for put a lot of importance on safety. As a way to improve the employees' awareness of danger, there would be regular meetings during which participants would need to identify dangerous points in a picture. The results were written down and archived on paper, which I believed could be improved. So, I created this web application.