Fish are ideal pets for people who don’t have a lot of time or space for other common pets. Whenever I am sad or on a hunt for new ideas the best thing I do is, watching fish in the aquarium. It really helped me in improving stress and getting a joyful moment amidst all the busy schedules of the day during the Covid Pandemic. It is also scientifically proved- "The hypnotic effect of watching fish swimming back and forth helps children calm down and relax... Watching fish not only lowers blood pressure and heart rate but reduces stress and anxiety, improving mood helping us to feel calm and relaxed. A natural and therapeutic tool to help children suffering from conditions such as ADHD and autism." So, when your marine friends add so much value to your life what are you waiting for, take care of them properly so that they can thrive. You don't need a big budget for that, it can be built easily with these cheap boards- Arduino UNO and ESP8266. I am also going to show you how easy and fun it is to build a cool internet-connected gadget and mobile app with the Tuya IoT Platform.

You might have come across several such IoT based aquarium monitoring projects from simple to advanced ones but I made this project to help people with no or lesser technical knowledge to set up one such aquarium IoT device with Android and iOS app having secure authorization built-in support as well.

What is Tuya and Why?

Tuya is a leading global IoT Cloud Platform that connects the intelligent needs of brands, OEMs, developers, and retail chains. The platform provides developers with a one-stop IoT PaaS-level solution that contains hardware development tools, global cloud services, and smart business platform development, Tuyaoffering comprehensive ecosystem empowerment from technology to marketing channels to build the world’s leading IoT Cloud Platform. Tuya is open to all, join as a beta tester and developer with their recent Arduino Library and Tuya Development kits release. Sign up and join the Tuya Developer Arduino Beta Test

I decided to use the IoT platform because it is simple, powerful and can run on cheap modules like Esp8266. Also, the Tuya IoT platform gives you a drag-and-drop MIT app inventor like feature to build your own IoT android and iOS mobile app on the go. So, your prototype can be the next smarter IoT product with the Tuya platform.

For more details on Tuya, check out my previous project on Introduction to Tuya IoT platform: https://steptostem.com/2021/08/getting-started-with-arduino-iot-control-with-tuya-iot-platform/

Let's build it

Hardware:

There are 3 sensors available to measure the key parameters in the fish tank such as temperature, pH and TDS. In addition, you can add many different actuators to automate tasks such as heating or cooling the water, feeding the fish, activating the pumps for water change or medicines administration, and controlling the intensity of the light to simulate the day/night circles. I will go into detail in this article.

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pH sensor: pH measures the acidity or alkalinity of water. A pH value of 7 is neutral, with lower numbers increasing in acidity and higher numbers increasing in alkalinity. Many fish can thrive in a range of pH conditions, typically spanning 6.5 to 7.5 pH. However, some fish require specific pH conditions outside this range. However, pH can drift over time, so testing aquarium water regularly is important. Most of the time, if left alone, pH levels will decrease over time due to the addition of acids into the water. Where could these acids be coming from?

Here are a few common sources:

1. Carbon dioxide in the air dissolving in the tank2. Tannins leeching into the water from plant matter3. Waste digesting bacteria acidifying the tank through the nitrogen cycle

Unfortunately, there are no visible indications that any change has taken place, so frequent monitoring is the only way to ensure...