4G, Wi-Fi or LoRa: Choosing Connectivity for a Field Device

The first question for any connected device is not which chip to use, but how it will reach the internet from where it is installed. A device that works perfectly on the bench is useless at a pump house with no signal. Here is how to choose.

The options at a glance

Wi-Fi: when the network is already there

Wi-Fi is the simplest choice for homes, offices, shops and greenhouses next to a building. The ESP32 has it built in, there is no running cost and data speed is never a problem.

Limits: range is short, walls and metal sheds cut it further, and the device depends on someone else's router staying on and keeping the same password.

4G LTE: reachable from anywhere

A 4G modem makes the device independent of any local network. If a mobile phone works at the site, the device can report and be controlled from anywhere.

Best for: remote pump houses, borewells, vehicles, construction sites and anything installed at a customer's site where you do not control the Wi-Fi.

Consider:

• Coverage: check the signal for each operator at the actual installation spot, not at the gate. An external antenna on a short cable can make a big difference.
• Running cost: every device needs a data plan. Most IoT devices send very little data, so the cheapest plans are usually enough.
• Power: 4G modems draw more power, with high peaks while transmitting. Mains-powered devices are fine; battery devices need careful design.

LoRa: many sensors, long range, years on a battery

LoRa sends small messages over long distances using very little power. A soil sensor on LoRa can run for a long time on a battery and still reach a gateway kilometres away across open fields.

Best for: many sensors spread over a large area (soil moisture across a farm, water levels in several tanks) where each sends a few readings an hour.

Consider: LoRa needs a gateway that collects the messages and forwards them to the internet, usually over 4G or Wi-Fi. It is not suitable for sending large amounts of data.

Bluetooth Low Energy: phone-range devices

Bluetooth is ideal for setup, configuration and devices used close to a phone. It is not a way to reach the internet from a remote site on its own.

A common pattern: Bluetooth to set up a device on first install, then Wi-Fi or 4G for everyday reporting.

Combining them

Real systems often mix technologies:

• LoRa sensors + 4G gateway: dozens of battery sensors across a farm, one 4G gateway at the pump house sending everything to the cloud.
• Wi-Fi with 4G backup: use the site's Wi-Fi normally and switch to 4G if it fails.

A quick decision guide

1. Is there reliable Wi-Fi at the exact install point? Use Wi-Fi.
2. Is it a single device at a remote site with mobile coverage? Use 4G.
3. Are there many low-power sensors over a large area? Use LoRa with a gateway.
4. Is it used close to a phone, or only needs setup? Use Bluetooth.

Our field automation controller uses 4G LTE so it works at remote pump houses without Wi-Fi. For a custom system mixing sensors and connectivity, our IoT solutions team designs the hardware, the backend and the dashboard together.