There is no best radio
Each wireless link is a compromise between three things: how far it reaches, how much power it uses, and how much effort it takes to set up and maintain. Pushing one of these up usually pushes another down. The useful question is not “which is best?” but “which compromise suits this device?”
The four below are common in maker projects. The descriptions are general; actual range and battery life depend heavily on the hardware, antenna, environment, and settings, so treat any figure you read as a rough guide and check the specification of the module you plan to buy.
Wi-Fi
Wi-Fi connects devices to a router and onwards to the internet. Its strengths are availability and speed.
- Range: typically room to house scale, and shorter through thick walls.
- Power: relatively high compared with the others. A device that must stay joined to a network can drain a small battery quickly, although devices that sleep and wake briefly can do much better.
- Complexity: low for the builder, since the network already exists and most hobby boards have it built in. You need to manage the network name and password, and cheap devices can crowd a busy network.
- Good for: mains-powered devices, cameras, anything sending a lot of data.
Placement of access points matters more than people expect, and the practical side of Wi-Fi coverage is its own topic. Many builders also prefer a wire for devices that never move.
Bluetooth
Bluetooth, especially its low-energy variant, is designed for short links between nearby devices, often with a phone.
- Range: typically a few metres to a few tens of metres, depending on the version and obstacles.
- Power: low, and designed for coin-cell and small-battery devices.
- Complexity: moderate. Pairing and the way data is organised on the device take some learning. Phone support is a major advantage, since nearly everyone already carries a Bluetooth radio.
- Good for: wearables, short-range sensors, devices configured or read from a phone.
The short range is a limit, not a flaw. It also reduces the chance of interference between neighbouring homes.
Zigbee
Zigbee is a low-power protocol for mesh networking, where mains-powered devices relay messages for others, extending the coverage of the whole network.
- Range: each hop is short, comparable with a room or a few rooms, but a mesh of many devices can cover a whole house.
- Power: low for end devices, which makes it popular for battery sensors and switches.
- Complexity: higher. You usually need a coordinator device, and devices from different makers do not always work together smoothly. Compatibility and pairing steps can be fiddly.
- Good for: many small devices in a home, such as door sensors, bulbs and switches.
Zigbee shares a common radio band with Wi-Fi and Bluetooth, which can lead to interference in crowded places; careful channel choices often help.
LoRa
LoRa is a radio technique for sending very small amounts of data over long distances at very low power. It is often used with a separate network layer on top, and the details differ between systems.
- Range: potentially kilometres in open conditions, much less in dense urban areas.
- Power: very low, so a small battery can last a long time if the device sends rarely.
- Complexity: moderate to high. Data rates are low, messages must be small, and you need a gateway in range or your own. Regional rules limit transmit power and how much of the time you may transmit, and these differ between countries.
- Good for: remote sensors, farms, gardens and anything that sends a short reading every so often.
LoRa is not a replacement for Wi-Fi. It cannot stream video or send large files, and it generally does not suit anything that needs a rapid response.
A quick comparison
| Wi-Fi | Bluetooth | Zigbee | LoRa | |
|---|---|---|---|---|
| Typical reach | Home | Room to nearby | Home, via mesh | Long distance |
| Power use | Higher | Low | Low | Very low |
| Data rate | High | Moderate | Low | Very low |
| Setup effort | Low | Moderate | Higher | Moderate to higher |
| Needs extra hardware | Router | Often a phone | Coordinator | Gateway |
The table is a simplification. Real products vary, and newer versions of each standard change the details.
Matching the link to the job
A few questions narrow the choice quickly.
- How much data and how often? Video needs Wi-Fi. A temperature reading every ten minutes can use almost anything.
- What powers the device? Mains power frees you to use Wi-Fi. A small battery points towards Bluetooth, Zigbee or LoRa. A realistic battery runtime estimate comes from the radio’s average draw, not its peak.
- How far away is it? Across a room is not the same as across a field.
- Who needs to reach it? A phone-only gadget suits Bluetooth; a whole-house network of sensors may suit Zigbee.
- How many devices? Large numbers favour a mesh or a gateway-based approach over many separate Wi-Fi clients.
- How much complexity can you tolerate? An unfamiliar protocol adds learning time and failure modes.
It is also common to combine links, for example battery sensors using a low-power radio to a hub, and the hub using Wi-Fi to reach the wider network. The hub then speaks a common messaging method such as MQTT messaging so that the radio details are hidden from the rest of the system.
Things that apply to every link
- Security. A radio link is only as safe as its set-up. Change default credentials, keep firmware updates current, and look at what is encrypted. Wider guidance is in the notes on connected project security.
- Rules and licences. Radio equipment is regulated. Use modules approved for your region, stay within allowed power and frequency settings, and follow local rules. Do not modify transmitters or antennas to boost range.
- Interference. Several devices sharing a band can degrade each other, and walls, metal and water absorb signals.
- Cellular is a fifth option. Mobile networks, including 5G networks, can cover places the four above cannot, usually at greater power and running cost.
Test with the actual hardware in the actual location before committing to a design. A radio that works on the bench may behave very differently in a metal enclosure or at the far end of a garden.