Using Bluetooth as an on off switch

Help & Support Robots & Kits
1

Hi, I’m thinking about using bluetooth as an on off switch as part of an automotive project.

I realise that currently rfid appears to be the way to go but long range receivers appear to be expensive?

This is the idea… I have a kit car that I have already fitted some capacitive sensors to open the doors but this does mean that any old joe can activate the sensors and open the doors. So I was thinking about fitting a bluetooth module in the circuit so that when I approach with my paired device (mobile phone) the bluetooth receiver will sense my device and automatically activate a relay which will provide the power for the capacitance sensors and thus unlock the car… sounds simple but I don’t know which bluetooth reciever to use and how to set it up… Or if there is one out there that I can simply pair up to and it will provide an output automatically when connected.

Alternatively if it is easier and more cost effective (same price or cheaper) to go the way of rfid with a sensing distance of 1m or more then I’ll happily go that way instead… My car has a 12v supply but I’ll convert it to whatever dc voltage needed to power the unit… I have a range of converters in my project box I can use or I’ll just build / get a dedicated one if neccessary…

I’m managing to mix my love of old cars and electronics… So I’ve ironically got a 40 odd year old car with lots of tech in it!

Thanks in advance, Soundcatcher

2

Thanks for the advice… Moving forward… Are there any bluetooth shields that can be paired with more than 1 device? I’ve got a bit further myself and I think I can use on of the larger relay boards to perform a few more functions within the vehicle but it would be handy if more than 1 person was able to drive the car without the need for me to lend them my phone in order to get into the car…

3

youtube.com/watch?v=6cAtso2tzMo i have done this for a garage door opener and it does work. hm1100 is hard to find but the hm1800 works just fine. i have found the hm1800 as low as $18 online and works great and you can pair 2 cell phones to it. no programming required…

4

and you can create your own apps using app inventor or down load the free app called tap it open where you can control 2 bluetooth devices with just tapping the screen

5

In order to achieve that functionality, you will need a Bluetooth receiver, a microcontroller (and probably a relay depending on the output strength you require): RB-Ard-34, and RB-Ite-39

You can program the microcontroller to periodically wake up and ask the Bluetooth module if there is a device connected to it. Once that is the case, you could unlock your doors for instance.