I'm building a wearable Bluetooth device. When a button is pressed on the device, it sends a signal to the user's smartphone and consequently an app on said phone. I'm an app developer with no engineering background - but I've been doing plenty of research.

A means of communicating a button press into a message sent to the phone is necessary. I'm told making this from scratch will cost about $30,000 to have a competent engineer design it. I'm trying to find ready made solutions, but am struggling to find a Bluetooth module with an analog input built in which is what I believe I need.

Is there a ready made solution for what I'm doing or some method, tutorial or kit available that I'm overlooking? It seems crazy to me that there isn't, but my research has been fruitless thus far.

  • \$\begingroup\$ Why do you need an analog input? \$\endgroup\$
    – Matt Young
    Commented Jul 7, 2014 at 19:45
  • \$\begingroup\$ Don't I? Or do I just need a button or some sort? \$\endgroup\$ Commented Jul 7, 2014 at 19:47
  • \$\begingroup\$ Sounds to me like you just need something with a few GPIO pins. \$\endgroup\$
    – Matt Young
    Commented Jul 7, 2014 at 19:49
  • \$\begingroup\$ Do you have a Bluetooth module in mind yet? \$\endgroup\$
    – tcrosley
    Commented Jul 7, 2014 at 20:12
  • \$\begingroup\$ BLE 112 but I'm flexible if something better emerges. Range isn't a huge issue, but size is and of course being able to incorporate a button. \$\endgroup\$ Commented Jul 7, 2014 at 20:28

1 Answer 1


To read a button press does not require an analog input. A module like the BLE 112 has several "general purpose I/O pins" (referred to as GPIO) so you can read the button via one of these digital pins.

Almost many Bluetooth modules do not allow you to run code on them, the BLE is one that does. So you can upload your own firmware into BLE, scan the GPIO pin for a button press (and also account for the switch bounce).

BTW there is no way this is going to cost $30,000 unless the quote included the design and cost of a mold for a plastic case and band, and even that sounds high -- should be more like $10,000 or so.

The cost of doing the electronics and firmware should be anywhere from $500 to $1000 (very rough estimate), and you would probably also need a flexible PCB designed (couple thousand dollars maybe). This does not include the cost of doing an iPhone or Android app.

So if you include the mold, electronics/firmware/PCB, and smartphone apps I guess you could be getting up close to $30,000. But as you can see the firmware/electronics design is a very small part of that.

  • \$\begingroup\$ The module I'm looking at is the BLE112. I've been told by their representative that I would communicate between the module and the device/app via BGScript (their own language) so I assumed I'd be coding directly onto the module. Thanks! I'm googling most of the keywords in your response and I'll check with BlueGiga if in fact their modules can't run code \$\endgroup\$ Commented Jul 7, 2014 at 20:34

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