Wi-Fi vs Bluetooth communications to android phone

Question

I am interesting in getting a device, (bare metal micro-controller with sensors), to communicate to an android phone.

The device is not wearable and the power difference between Bluetooth and wifi as a consequence is of no import.

The range only needs to be a maximum of 3m with a low data rate (<2.1 Mbit/s), so bluetooth would be ideal and something I would just select. However, I am being questioned, why not WiFi?

What are the major advantages for WiFi versus Bluetooth for such an application?

e.g Are there any cost or regulatory implications for choosing one technology over the other?

Answer 1

Bluetooth (BT) will be overall more reliable. The android device can connect to more than one Bluetooth device but usually only one WiFi device and this you likely want to be a device providing Internet access such as a WiFi Access Point (AP). The Android device will "randomly" connect to more advantageous WiFi signals in its vicinity whereas with Bluetooth it will reliably maintain its connection with any authorized Bluetooth peripheral. A WiFi peripheral will require direct interaction to get it setup on a WiFi AP whereas a BT peripheral can pretty much be turned on, connected to and used straight away.

For an IoT (Internet of Things) sensor device that doesn't need to do much of its own processing or interaction with the RoW (rest of world), Bluetooth is the way to go.

Answer 2

Wifi allows for multiple connections. A standard wifi device, connected to a wifi router, and likely the Internet through it, can communicate with anything on the network (and with proper routing, the internet). A Bluetooth device is typically just node to node, as in only one device can directly talk to it, without a specialized bridge (bluetooth to ethernet/wifi/whatever).

Considering bluetooth and wifi modules are tiny now, and power is not a concern (BT beats Wifi by a small margin), interconnectivity/distance is the only difference in application.