i am planning on making a button that is when pressed sets an alarm on my phone. I am planning on making an app that is creating the actual alarm, the app just have to be triggerd by the hardwere button.

my question are:

Is this possible without a server (or is there a way to send direcly to the phone, bluetooth maybe?)?

Can the app be triggerd even if it is not running? (the app should just be installed on phone but you dont have to open it in order for it to recive the signal)


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    Why build this when you can buy it from flic.io? – hardillb Jan 9 at 10:00
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    flic.io is a product of shortcut labs, who are based in Stockholm, so you could go knock on their door ;-) – hardillb Jan 9 at 10:29

You could hack an Amazon Dash button since they are cheap.

Or use something like a raspberry Pi Zero W, which is also cheap.

And both of there are much cheaper than @hardillb's suggestion of Flic.io, where prices start at $34.99 for a single button.

If you don't like those for some reason, take a look at AdaFruit. They have some interesting wearables, such as the Flora which also has a BT Low Energy version.

Sounds to me like this is a fun learning project, so why not go a bit Rube Goldenberg and set your alarm by hairbrush?

Your app will need to be running on your Android (or something to wake your app, or something to wake that something ... there has to be something to realize that someone wants to talk to the phone, even if it’s just a broadcast listener).

Be aware of our Android enthusiasts sister site.

  • A Amazon Dash button is wifi so would require something on the same network to listen for the ARP packets and then send a push message. A BLE button is the correct solution to the problem as stated, building one from off the shelf dev kits is relatively trivial. A flic button may seem expensive, but when you factor in development time (for both hardware and app) and the fact that they have built a very neat little package that you couldn't possibly reproduce at home it's not outrageous. – hardillb Jan 10 at 8:46
  • Sorry, but I don't understand your point about WiFi - my bad and I want to learn. I imagine we are talking HTTP and RESTful API to say that the button was pushed? If so, both need a "server" which is the 'phone to listen for HTTP (?). I don't object to Flic, although I wouldn't use it myself on price grounds. The OP has been rather vague, so we don’t know if this is a “make it fun” learning project, or something more serious. Maybe if he updated the question with more detail, we can give better advice.; but I imagine that he is just collection ideas of now, so let’s throw some at him :-) – Mawg Jan 10 at 9:01
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    The Dash buttons can only make a call to Amazon's purchasing API (unless you buy the demo IoT button which costs about the same as flic button). If you want to use them for something else then you have to not configure them properly and then sniff the network for their IP address request packets to trigger events. – hardillb Jan 10 at 9:12
  • Thanks for clarifying (+1). Hacking them is one of those things that was perpetually in my ToDo list, as fun; but then the Pi Zero W came along ... – Mawg Jan 10 at 9:13
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    Big thanks, I have only developed frontend and apps before and i am new to IoT things. some projects i was thinking of: a button that is pressed when i sit in my chair and sends a signal to an android app to notify me when i hav ebeen sitting down for too long, and also making my "dumb" blinds smart – Lukas Petersson Jan 10 at 22:04

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