Projects for the New Place
Been thinking a bit lately about projects to keep me busy in the new apartment, and I’ve got a couple of ideas that I think will be pretty neat.
First, I’ve been interested in tracking the temperature in my apartment. There is only one thermostat, and I can’t think of a good way to pull any info off of it, so I’ve been looking into other sensor equipment. The iButton stuff looks pretty promising; the temp-only sensor buttons are pretty inexpensive, and the HA7Net looks like a good way to interface to them without having to mess around with line level protocols. Since I don’t use the landline phones, I’m thinking I’ll cut off the connection to the phone company and reuse the existing phone jacks in the apartment to make a 1-wire bus. Just solder an RJ-11 plug onto the temp sensor iButtons, and I can put a sensor everywhere there’s a wall jack! The controller is about $155 and the sensors are $7.50/each in the quantities I’d be looking at.
The other thing I’d like to monitor is power consumption. I’ve got a Kill-a-watt, but that only works for a single outlet. I’ve been eying The Energy Detective, which installs into your breaker panel with a number of inductive probes and a connection to communicate it’s readings over the power lines (similar to X10.) The only problem is their software is currently only for Windows. The older version had a serial port on the receiver to communicate with, the new version has USB, and I suspect it’s just a USB to serial adapter of some kind. To do what I want to do (feed the data into Munin) I’d have to figure out how to talk to the thing, which might make for a good project. T.E.D. sells for $145.
I’m also going to need a new vacuum cleaner. The old one is Delia’s, so it’ll be going away. I’m leaning toward spending the extra money and buying a Dyson, specifically the DC 25. The reviews are all very good on them, and it sounds like they last forever. Seems like one of those things where it’s worth to spend the extra up front and get something you’re happy with instead of skimping and replacing it later because you hate it.
Get a Dyson. In the long run it will save you money because I went through vacuums every year because the store no longer stocked the bags and then it would cost a lot to ship them from one supplier that was hard to find! Don’t believe in any of the other bagless vacuum cleaners as when you go to empty them, the dust is all loose and flys everywhere! But yes, 5 year warranty on many. Really worth it!
Hey – another way to (cheaply) measure temperature is to use the BasicStamp I gave to you years ago and a bunch of thermistors. You use the RC Time function on the stamp to measure how long a capacitor takes to discharge through the thermistor – since thermistors vary resistance with temperature, the time to discharge is relative to the temperature. They are cheap – two wire devices, so you could still use the extra two wires on the phone line!
Let me know if you need details – I have the references at work on how to make this work!
Also concur on the Dyson!
Now that is a good idea. I think there was some info on reading thermistors in the book that came with the BasicStamp, I’ll check it out. I assume some sort of calibration would be needed once it was in place, since the length of the phone wiring to the thermistor would impact the discharge rate. I don’t know if that would be significant or not.
Yes – you would have to calibrate them in-situ. However, they all should have the same temp/resistance characteristics so if you calibrate one prior to connecting it via the phone wires, that should give you a calibration curve – in the zone you are interested in (probably 50 to 90F), you can probably make a straight line conversion. Then, when installed via the phone, the cal will shift slightly – but the curve will remain the same, so a couple of cals compared to a “regular” thermometer (get a good one) should do the trick!
If you get “brand name” thermistors, they may even have resistance/temp curves that will save you the first calibration. In any case, you can probably get it to within 1 degree!