Cross platform

[Sten Jensby]

Hi.

Need to make an APP that share some smal data(10-15 bytes) with a windows based .

What kind of database / ftp or what to use ?

The App should send the info, and the windows app should act on it, so not long delay in data connection.

Think that dropbox could be an answer.

[Chris Ward]

Hi Sten

Not a long delay in data connection? Surely that would mean ftp/dropbox do not qualify?

Is it the case that the Android device is remote from the Windows device? What sort of distance away: 5 meters, 500 meters, 5 Kilometers, another country?

[Sten Jensby]

Distance is up to 2-300 meter.
Need it for opening a door,have tried sms but then i have no chance of control it. Ring in is also possible but cant make directCall so that is no go.
If i just can save a text file or something and the window comp then see it and act on it.

[Sten Jensby]

Here more details in how i want it to function.

Every user has a phone(app) that when pressed button should open door, by sending "phonenumber.open" to keep track of "granted access"

After command is send, it should check for status in the DB.

The Windows part will allways check for "phonenumber.open", and when "arrives" , check if user may open the door, and then send Command to Door.

Save a status bit in DB that door is open, or access denied,

That part by windows programming i can handle,

I also can make the Android app,, but it's the sharing part than i need help to.,

How "slow" is dropbox ? 1-2 sec could be ok.

[TimAI2]

Isn't there a proximity issue here, i.e. that those equipped with the app (when working) will be able to open the door from wherever they are (possibly, in the world!)

Wouldn't it be better to use NFC / RFID Tags on the door location ?

[Chris Ward]

Hi Sten

I would probably limit the distance to avoid signal interception. Initializing the process from 5 meters away should probably be the max. 

[TimAI2]

But how does the door know where you are/your device is ?

OK GPS, but this relies the the user having GPS turned on.

[Sten Jensby]

The issu is that the residents should be able open door when they ex is on 3 floor and got compagny ex pizza man😀. So promity sensor is no go.
Yes i know they could open from another country but they are students and only live here for a couple of years. And can easy remove phonenumber if they are away

[Chris Ward]

.....Using Dropbox/ftp would take longer than that, the PC needing to constantly monitor for changes. However the main issue would be reliability - If the PC lost it's internet connection, the door could not be opened.

I think you can do it securely without a database and without a Windows PC. Your plan is to only allow people with security clearance to open the door. Your current scheme does not cover the possibility of a phone being in "the wrong hands". 

I assume that the Windows PC uses a microcontroller to trigger a relay switch that unlocks the door. The microcontroller can store the phone number access data (presuming only a few people) and the communication could then be Bluetooth.

[Sten Jensby]

Well cant handle the fact that someone can steale a phone, but user may have a code on phone, dont see that as a problem...

By using BT , user also need to have BT enabled,  then again BT only works on some meters,,

Dataconnection is the best for using here,  

SMS is not ok,,  can't lock the numbers out,

Call in , could be an answer, but again google prevent me from sending direct calls,

As it are today, the users just gets a code , and now many have the codes, 

I know i cant prevent people from "joining" access together with Granted people, but most people i can lock out.