Sensors for boats, sensors for homes. Sensors!
March 27, 2013 5:28 AM   Subscribe

I'm inthe process of designing a comprehensive refit of a 21 Metre Dutch Barge and thought it's about time I made at least a small amount of use of my Robotics background. I'm thinking about including a vast array of sensors throughout the inside and outside and feeding it all into a central computer, then probably using these sensor feeds to do various automation actions. So this question has a few parts, some technical and some not.

1) If you could record any data (money and practicality being no object at all) in your house or in your boat, what data would you want?

2) Have any of you done this sort of thing before? i.e. home automation or smart home type things. What was a really bad idea? What did you wish you'd done?

3) If so, do you have any suggestions for sensors or busses or controllers?
I was thinking about using an I2C bus for various sensor grids, if only because I've used one before, but I'm not sure I can address several hundred sensors using it. Is there a better bus to use?

4) What have I stupidly not thought about?
posted by Just this guy, y'know to Home & Garden (10 answers total) 7 users marked this as a favorite
1) Energy (electricity and fuel), fresh water and waste water levels and usage (for planning and efficiency). Water sensors in the bilge obviously.
4) Electrolysis.
posted by 445supermag at 5:48 AM on March 27, 2013

Since I've used I2C a lot, a few comments:

1. Despite most everything *nominally* supporting 10 bit addressing, you'd be surprised how many devices don't give you full access to the addressing range, so I've often found that pushing it past 64 devices usually results in a lot of issues.

2. Clock stretching and signal attenuation can be a real issue for large numbers of devices.
posted by kaszeta at 5:52 AM on March 27, 2013 [1 favorite]

Sensors on all doors. Maybe a little indicator by your bed that shows which ones are open. I sometimes forget to close my garage door at night, which basically leaves a way into the house, so it would be nice to know it's open before I go to bed. If you can have one open/closed sensor and one locked/unlocked sensor, even better.

For heat, I think a Nest thermostat would do most of what you want. I would have thermometers in all heating zones and one each in my unheated basement and garage. It would be nice to record the yearly low and high temp in the unheated areas. You could then use these thermometers to control heating throughout the year.

Sensors anywhere water might leak and cause a flood. I have my washer/dryer on the 2nd floor and I sometimes wonder what would happen if a pipe burst while I was away. I'd be fucked, is what would happen. I know you can buy a sensor that will control a water shut off and I keep thinking it would be nice to have.

Track the sun. Automatically controlled blinds that open and shut depending on where the sun is.

Honestly, most of the home automation I've looked into seems somewhat pointless, more a hobby for its own sake rather than for anything too practical, but I think with a few things like I've mentioned you might actually find some benefit without overdoing it.

For a boat? I don't know. Maybe a sensor that tells you when you're out of beer.
posted by bondcliff at 5:52 AM on March 27, 2013

I'd want a carbon monoxide and smoke sensor too if you are going to be burning gas or fuels on board. Not so much for recording, but as an alarm.
posted by MuffinMan at 6:05 AM on March 27, 2013

If your barge has AC wiring, early home automation systems like X10 are very sensitive to voltage/frequency fluctuations. X10 (both powerline and wireless) is quite slow and has no encryption, but it's very, very cheap. More recent wireless systems like Z-Wave and Insteon are more secure, and actually support status verification and retries. X10 is write-only.

An external GPS antenna talking to gpsd on a Raspberry Pi gives a very good basis for time and position sensing. From that, you can calculate sunset and sunrise times, and with a bit more work, tides.

My biggest concern would be water- and corrosion-proofing of the system.
posted by scruss at 7:30 AM on March 27, 2013

Do you know about these?
posted by segatakai at 7:35 AM on March 27, 2013 [1 favorite]

If money were no object, in addition to the items already mentioned, I'd want:
  • a weather station (temp/humidity/pressure/wind/solar radiation/precipitation),
  • a three-axis accelerometer/gyroscope/magnetometer sensor-suite at both the bow and stern,
  • a rotational displacement sensor for the rudder,
  • a freeboard height sensor,
  • a suite of engine diagnostics sensors (engine temperature, oil pressure, oil temperature, engine RPM),
  • a recording all-sky camera, and
  • a 24/7 recording microphone far from the cabin/engine for recording ambient/environmental sounds.

posted by RichardP at 8:14 AM on March 27, 2013 [2 favorites]

@scruss: X10 can be bi-directional, but the modules are a lot more expensive (and it doesn't change the fact that X10 isn't particularly great for these things, especially if you're likely to have voltage or frequency fluctuations).
posted by kaszeta at 8:35 AM on March 27, 2013

Are you using propane? The sensors seem to be very expensive and proprietary but a couple in the deepest part of the bilges might relieve some worry. How about a running depth log?
posted by sammyo at 8:57 AM on March 27, 2013

I built a simple apartment monitor for myself - my main considerations were more learning about my own habits / environment rather than energy conservation, etc. I have PIR, visible light, sound level, humidity, and temperature sensors for my living room. The intention is to log the data and be able to see behavior patterns over time, as well as to get a better understanding of my preferred environment temperature/humidity wise.

So for your project, I would think about door sensors in addition to the above sensors - then you could get an idea of how often spaces are being used, what the preferred environments are, etc. A really comprehensive system that can see changes in temperature/humidity due to doors being open between rooms, etc might be neat.

Also, I don't know if you were planning on having the whole thing be wired, but maybe a two-stage system with local nodes communicating using I2C and connecting to a master computer via wifi?
posted by ianhattwick at 10:09 AM on March 27, 2013

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