Cheapest way to power an LED from an Android phone using Bluetooth [closed]

Question

I recently wanted to make an Android controlled LED using Bluetooth.

The obvious solution I could think of is using a HC-05/06 module with an Arduino.

However I believe for just lighting an LED, this method is overkill, and not really cheap.

Also I wouldn't want to use an entire Arduino board for this as a lot of its functionality would go useless.

And I only need to transmit a 0 or 1 through bluetooth-nothing else.

So is there any cheaper way of Bluetooth controlling the LED?

I would prefer something with minimal features that serves the purpose.

(Being just a high school student I don't have much experience and resources to do the same so please guide me accordingly).

Thanks!

Answer 1

Bluetooth is a complex protocol. Handling it really requires some kind of programmable state machine – in the end, a processor. So, even the least complex bluetooth device will always contain a dedicated processor, for the sole purpose of "talking" bluetooth.

It also needs to contain a lot of radio hardware – DACs and ADCs, oscillators, amplifiers, mixers…, which ideally should be placed on a single IC, to avoid complexity and imperfection.

Therefore, standards like Bluetooth, which are meant to go into a lot of cheap consumer devices, are designed with one thing in mind: Integration into ICs that also contain other functionality.

Therefore, literally hundreds of Systems on Chip (SoC) containing both a bluetooth frontend and a programmable microcontroller exist. A module with such an SoC sounds like what you need (example). Most of these are cheaper than official Arduino boards.

By the way, don't underestimate the complexity of bluetooth: Compared to what a bluetooth frontend needs to do to receive a couple of bits, whatever you've been writing on an Arduino will look very small. Luckily, the SoCs mentioned above do all this for you. You just have to write a very simple firmware for the microcontroller on the same chip as the bluetooth controller.