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Homebrew Input Devices

Anyone had any practical experience of doing this?
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My latest "thing" is gathering huge data sets and analysing them for patterns.

What would be cool* would be to wire up my flat with various sensors, taking readings every now and then allowing me to plot with accuracy the number of times I open the fridge, to track seasonal variations in temperature, or to analyse the frequency of the postman.

It's pretty simple to deploy a microswitch, or a light-sensor, or a temperature sensor - but what's trickier is reliably transmitting, gathering and logging the data each sensor generates in a central location.

I heard that labs-on-chips often use special electronics to send encoded signals to a machine listening on the serial port, running some clever decoding software and reporting the results to a log file.

Has anyone actually tried this?

What bits do you need, and is there a nice short-cut method you can use?

To the idea, it might be handy to build a common, generic platform, into which you can plug your various sensor/control devices - which syncs up with some decode/control software that you can configure to do what you want - a sort of sensor kit that doesn't involve too much soldering. I've googled this, but all of these projects so far seem to be either heavy-duty impact-plastic industrial units that you simply couldn't sticky-tape to the back of the fridge door, or tinkery kitchen-table type affairs, requiring skills (soldering, circuit diagrams, basic electronics) that I don't currently have - even worse, I don't have a kitchen table.

What I want (and what forms the non-consumer-advice request part of the idea) is to take a transmission module A, plug in sensor type B and have it transmit a signal to receiver unit C plugged into a serial cable (or USB cable perhaps?) plugged in the back of an always-on computer and pipe up to say 127 different data collection streams into text files on my computer. These streams could be in the same format: timestamp, signal value for all sensor types - the timestamp being provided by the server.

*the reason it's cool is that once you've started gettting data *in* to your computer about the outside world, you can start thinking about ways to tell your computer to *do* stuff to the outside world in response - like turning lights on or off, triggering the burgular alarm, or releasing the bees.

zen_tom, Feb 02 2010

First thing that comes to mind is that T-motes could be useful... http://www.sics.se/...s-sky-platform.html
[bigsleep] has the data acquisition covered; I've got your transimssion covered. Sorted. [Jinbish, Feb 02 2010]

What do you think of this then? personal_20clock
My idea for a clock, virtually the same as most of this idea. [zeno, Feb 02 2010]

Homebrew Input Device http://www.homebrew...-plastic-funnel.htm
Widely available, for various applications, in various sizes [pocmloc, Feb 03 2010]

Raspberry Pi http://www.raspberrypi.org/faqs
Getting a bit evangelical over the prospects delivered by these little devices - but at $25 a shot, you could build a series of these devices to collate/monitor and transmit pertinent data all around your home network for whatever purpose you chose. Geez, with a bit of electronics you'd be able to create self-propelling Pi's to wonder about the place. [zen_tom, Apr 08 2012]

[link]






       You realise that this can open up a whole "Context-Aware" can of worms...
Jinbish, Feb 02 2010
  

       If by "context aware" you mean that a sensor that's reporting something unusual might be undergoing something unusual - e.g. a door sensor that's constantly reading open might, rather than suggesting that the door really is open, may just have fallen off the door - then yes...ish.   

       But the (long term) applications I have in mind are more managerial/informational, what time does the heating switch on, how long can I sensibly expect to wait in for the postman, do I keep leaving the windows open, on what days was I in (assuming that for example Fridge Door operation denotes being at home) Nothing exceptionally useful perhaps, by logging, collecting and analysing all this data together, some interesting (and useful?) patterns might emerge.   

       Hmm, re your links [bigsleep] & [Jinbish] you make the point that both parts of the idea are covered. Some of those data aquisition hubs are 90% there, but still rely on wired transmission - and the T-motes seem to contain light-sensors only - but that's a start. What would be great would be to be able to buy a bag of assorted units, each around a 1 to 1/2 inch cube, some might be temperature based (red ones) others report the amount of ambient light (white ones) some might contain accelerometers and detect motion (grey) or sound (green) or humidity (light blue) or bacon (bacon) and be placed (scattered?) around the flat. The base unit plugs into the back of your machine, and takes wireless readings at regular or triggered intervals, storing the data to a file. If one breaks, you either change its battery, or replace it with another one. I know it's smart-dust writ chunky (and so, not a particularly original idea) but it is interesting to think how you might be possible to build something like this using known technology, at home.   

       Expanding it further, having the ability to register these devices onto a host "node" would potentially allow you to hook multiple nodes together through internet technology and eventually spawn a global sensory network.
zen_tom, Feb 02 2010
  

       sorta being OCD about OCD eh?   

       hmm... if you look in the home-security automation field, you'll probably find plenty of make/break sensors and collating equipment.
FlyingToaster, Feb 02 2010
  

       You need a D/A box. They can be had with almost any number of channels, level of precision, and resolution of sampling. They also come in "user friendly" sensor identifying and self calibrating kinds. This is very much not a novel idea. D/A boxes with digital or analog outputs are also widely available. If you are scared of programming many manufacturers can hook you up with a programmer who will set up your data recording and write simple Macros for you. [Marked-For-Deletion] Already widely available.
WcW, Feb 02 2010
  

       Tell me more about it [WcW] (this is half idea/half a call for someone wise in these things to explain some of the practical problems/techniques to watch out for) I'm happy with programming, though not low-level driver-type stuff - but if someone shows me how to call an API, I'm fine with the rest - but I'm less confident with a soldering iron, and anything that I've built always looks like it's been salvaged from the smouldering wreck of a vehicle.   

       I recently bought myself a great big sturdy castor mounted box that in addition to containing the usual home-network type stuff is also getting populated with a bunch of old computers that I wanted to put back to use - Data Aquisition seemed to be a reasonable job for them to be put to.   

       But, I don't necessarily want to drape wires all around everywhere - I've just managed to put all this old gear into a nice, tidy, modular, manouverable location, and I'd rather not tie it all down again with an intricate web of signal wire going everywhere - a D/A box sounds fine, but it doesn't solve my problem, which is to perform all the functions of a D/A box, but without all the wiring.
zen_tom, Feb 02 2010
  

       I use siphon hoses.
normzone, Feb 02 2010
  

       My original thought was Arduinos and ZigBee/XBee but that would get expensive quick unless you want to set up hubs as The Arduino can tally many inputs and send them all in to the central PC. But probably the easiest solution is to add a RF signal on to your house wiring and then have a board on your computer to listen for those signals. This could also be done with Arduinos and some basic RF circuits or a bunch of minimalist crystal oscillator circuits to send binary data. You could probably AM modulate modem tones on a RF carrier for a couple a bucks a piece.
MisterQED, Feb 02 2010
  

       Honestly the kind of thing he's going to use is going to be more like 199$ from any purveyor of precision electronic devices.
WcW, Feb 03 2010
  

       Arduino? Circuit Playground Express? ESP8266? Wink Hub? Node-RED? Phant?
notexactly, Apr 09 2019
  
      
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