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ESP32 boards are popular for home projects because they’re small, versatile, and, most of all, cheap. Not only are ESP32 boards affordable, but if you use them for the right projects, they can also help you save money. Here’s how.
Set up a whole-home energy monitor
Track your total power usage for less
An energy-monitoring smart plug can tell you how much energy an individual device is using, but it can’t monitor your entire home. With an ESP32 and some other hardware, you can do exactly that.
By connecting current transformer clamps around the live supply conductors in your breaker panel, the ESP32 can estimate how much current your home is drawing without needing to cut the wires. You can use this information for real-time power and energy monitoring for your whole home, helping you identify ways to make it more energy efficient.
For safety reasons, you should have a qualified electrician install your energy monitor, as there is a significant risk of electrocution.
Make your dumb thermostat smart
Don’t pay to heat or cool your home when you’re not in it
A smart thermostat can save you money by allowing you to automate your heating and cooling. Instead of continuing to run when you’re away from home, for example, you can use geofencing or other presence detection methods to pause heating or cooling when no one is home.
Smart thermostats can be expensive, but you can use an ESP32 and appropriately isolated relay hardware to control a compatible low-voltage heating or cooling system remotely. You can also use ESP32 boards to build temperature sensors and place them around your home so that you can control heating and cooling on a room-by-room basis.
A homemade presence sensor
You can stop heating empty rooms
Using geofencing to determine when you’re away from home means that you can stop heating or cooling your home when no one is in it, but with the right sensors, you can do the same for individual rooms. There’s no need to heat or cool your bedroom if you’re not using it all day, for example.
Knowing when you’re in different rooms is the challenge. A motion sensor can tell when you enter a room, but it can’t tell when you leave; if you sit still enough, the motion sensor may think no one is there and turn the heating off.
A presence sensor can solve this problem by detecting when people are in the room, even when they’re still. Presence sensors can be expensive, but you can build them relatively cheaply with an ESP32 and an mmWave sensor module such as an LD2410.
Build a cheap water leak detector
It could save you a lot of money
A water leak sensor is something you hope you never need to use. However, if you ever do need one, it could potentially save you a small fortune. Discovering a water leak before it has time to cause a lot of damage could save you from an expensive insurance claim, or worse.
Water leak sensors aren’t too expensive, but by connecting an inexpensive water-detection probe or conductive sensor to an ESP32, you can build one for even less. This means that you can afford to put more water leak sensors in more places, increasing your chances of discovering a water leak when it happens.
Set up a water usage sensor
Know if there are leaks you can’t see
Even if you have multiple water leak sensors around your home, a leak can still happen somewhere out of sight or inaccessible. This can go undetected for some time, causing your water bills to rise as your water supply quietly leaks away.
Depending on the type of water meter in your home, it may be possible to use an ESP32 to count the pulses from the pulse output of the meter. The ESPHome pulse meter sensor component can be used to turn those pulses into a flow rate that you can use to figure out your water consumption. You can also use a camera connected to an ESP32 to read the meter directly.
If you detect unexpected or continuous water use, it may be a sign that there’s a leak in your home. Finding the leak early can make a huge difference.
Pro-level air quality monitoring for less
Branded air quality monitors aren’t cheap
While most of us are aware of the risks of air pollution outside our homes, we’re not always so aware of the pollutants that are found inside them. Poor indoor air quality can have health implications, so being able to measure the quality of air in your home is important.
Unfortunately, many good air quality sensors are reasonably expensive. With an ESP32, you can build your own for less. You can add sensors that can measure things such as PM2.5, carbon dioxide, and VOCs, as well as temperature and humidity, so that you can be aware of when the air quality in your home is poor.
Make your own subscription-free video doorbell
No need to pay Ring to replay your videos
Video doorbells are one of the most useful smart upgrades to a dumb device, allowing you to see who is at your door without having to be there in person. However, many popular models require cloud subscriptions to use features such as recorded video history.
If you don’t want to have to pay, you can build your own simple video doorbell using an ESP32, a button, and a camera module. While it won’t match the image quality of popular branded doorbells, it can provide a usable live image and snapshots without any subscriptions at all.
Money-saving ESP32 projects can be cheap to build
The beauty of all of the projects on this list is that they can help you save money and can also be built relatively inexpensively. The low cost of ESP32 boards means you could build every project on the list without spending too much.
