The internet is an amazing thing. You can build incredible internet-connected projects using cloud services, but there’s always a risk that if your internet connection goes down, your project will stop working. There are plenty of useful ESP32 projects that don’t depend on cloud servers and can communicate locally or directly with other devices, so they’ll keep working even when you can’t get online.
An ESP32 Bluetooth proxy
Expand Bluetooth coverage around your home
This is one of the simplest things you can do with an ESP32. Onboard Wi-Fi and Bluetooth means that you have everything you need to create a Bluetooth proxy.
Bluetooth is a short-range communication protocol, so it’s not always a great fit if your Bluetooth devices are scattered around your home, a long way from your smart home hub. If the devices are out of range, your smart home simply can’t communicate with them.
A Bluetooth proxy solves this problem. You can place one in the same room as your Bluetooth devices, which can then communicate directly with the proxy. The proxy sends the relevant data back and forth to your smart home hub over your local Wi-Fi network.
It’s effectively as if your smart home hub was in the same room as your Bluetooth device, even if it’s actually on the opposite side of your home. Since all communication is over Bluetooth and your local Wi-Fi, as long as your local network is up, your Bluetooth proxy will keep working when the internet is down.
A long-range mailbox alert with ESP-NOW
Get notified when mail arrives
A Bluetooth proxy that communicates over your local network will still work when you don’t have external internet access. If your home network goes down too, however, it will stop working.
ESP32 devices don’t have to rely on Wi-Fi for communication. ESP-NOW is Espressif’s connectionless wireless communication protocol that allows ESP32 devices to communicate directly with one another without needing a router. You can use this to build projects that will work even if your router dies.
ESP-NOW is also very useful for situations where your Wi-Fi signal may be too weak to be effective. For example, if your mailbox is a long way from your house and is beyond the range of your home Wi-Fi, you can set up an ESP32 connected to a reed switch in the mailbox and have it communicate with another ESP32 in your home using ESP-NOW. When mail arrives, the ESP32 in your home can flash an LED to tell you that mail has arrived, and it all works without using your home Wi-Fi network at all.
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Off-grid communication with Meshtastic
A messaging network that doesn’t need the internet
ESP-NOW isn’t the only way to use an ESP32 to communicate without relying on your home Wi-Fi network. If you want communication that extends beyond your mailbox, you can use Meshtastic. This is firmware that can run on ESP32-based boards equipped with LoRa radios.
These devices can become part of a mesh network that can pass messages over long distances without the need for Wi-Fi or cellular networks. The data is carried by radio waves, and with a clear line of sight and well-placed antennas, messages can potentially travel many miles in a single hop. With data passing from node to node, messages can travel even farther, but real-world range depends heavily on terrain, antenna quality, and local radio limits.
- Dimensions (exterior)
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4.5×1.3x.1.1 inches
- Compatibility
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Meshtastic
- Battery life
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1100mAh
- Connectivity
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LoRa, Bluetooth, Wi-Fi, USB-C
These two LoRa radios are Meshtastic-ready so you can hit the ground running in building a mesh network that you can send messages over long distances. They have OLED displays, 915MHz antennas, USB-C connectivity, and Wi-Fi and Bluetooth support.
A local video doorbell with an ESP32-CAM
A camera that streams to your local network
Video doorbells can be really useful, allowing you to see who is at your door when the doorbell rings. The problem with many popular video doorbells is that they rely on the cloud. If your internet goes down, you can’t view the live video feed, and it turns into an expensive dumb doorbell.
An ESP32-CAM is a cheap development board that combines an ESP32 with a small camera module and a microSD card slot. You can use one of these boards to build your own local video doorbell. The camera can stream over your local network so you can see the live feed on a dashboard, or you can send snapshots from the camera as a notification to your phone when someone is at the door.
You get some of the core features of popular products such as Ring doorbells, but everything runs over your local network. Even if the internet is down, you’ll still be able to see who is at the door.
An always-on E-Ink dashboard
Display local smart home information
You can hook up an ESP32 to a low-power E-Ink display to create a stylish smart home dashboard. The low-power nature of E-Ink means that you can leave the dashboard on all the time without chewing through batteries or requiring constant connection to a power supply.
You can use the display to show information pulled from sources such as your smart home, meaning that the information is served over your local network. Even if the internet goes down, your dashboard will keep working as long as your local network is up and running.
The same isn’t true if your dashboard is displaying data from external sources. Weather data pulled from a cloud service will stop working if you go offline, but weather data from a local weather station will keep working whether you can get online or not.
You don’t need to rely on the internet
A good smart home should have a strong focus on local control. You don’t want your projects to stop working because your ISP or a cloud service is down. There are plenty of ESP32 projects you can set up that will happily carry on working offline.
