kellym@ether.UUCP (Kelly M McArthur) (01/06/91)
I'm interested in building a gizmo that will allow me to monitor local weather conditions on my PC. Specifically, I would like to stick a data aquistion contraption on my roof, and have it send information about current temperature, wind speed, wind direction and barometric pressure to my computer.* The PC end of things, software and parallel/serial ports, is clearly pretty generic. But I'm interested in any clever ideas people might have for building the outdoor sensors. My ideas so far include: Temperature- the easy one. Reverse bias transistor junction, amps, A/D. Something like that. I'll have to look it up... Wind Speed- Say, if we need an A/D, and some kind of communications like twisted-pair serial, let's throw a 68HC11 in this thing. Then we can bag the DC-motor-attached-to-a-model-airplane-propellor annemometer, and go with a fan that interrupts the beam of an LED/ phototransistor pair, and have software do the rest. Hmmm... Wind Direction- Let's see. If I'm only concerned with approximate wind direction, N, NNW, NW, WNW, W, etc. that means I only need to resolve things into 16 possibilities. Cool. How about a simple Gray code wheel and four LED/Phototransistor pairs for a simple shaft position encoder? Barometric Pressure- Uhhh. Well, I guess I need one of them Pressure Transducer things. Kind words of advice in this area would be greatly appreciated. Time- another cool function might be to listen in on WWV to set the time on my computer with reasonable (but not fanatic) accuracy. I think this has been discussed before. Anyone have the details on how to do this? If you have any suggestions, send me mail and I will summarize your collective brilliance in a followup posting. * Yes, I imagine that such things are commercially available, but I'm interested in trying to hack one together myself for the fun of it. (a foolhardy notion I'm sure I'll live to regret) ----------------------------------------------------------------- "We [Americans] don't know what we want, but we're ready to bite someone to get it." -Will Rogers -- ******************************************************************** * Kelly McArthur ..tektronix!sequent!ether!kellym * * HALF Associates (Heavily Armed Lunatic Fringe) * ********************************************************************
lairdkb@mentor.cc.purdue.edu (Kyler Laird) (01/06/91)
(Sorry to post, but I can't send to a UUCP connection.) Hacking together a weather monitor should be quite a bit of fun (and reasonably easy with a 68HC11...), but just so that you know what you're passing up: _Heathkit Winter 1990 Catalog_ Advanced Weather Computer Kit 499.95 *Assem. 999.95 This has a nifty display and keyboard for standalone use. Functions include wind speed and direction, indoor and outdoor temp., barometric pressure, day and date, min. and max. recording, wind chill and fog likliness calculation... *assembled includes RS-232 interface and humidity sensor Indoor/Outdoor Relative Humidity Sensor Kit 59.95 Rain Gauge Snesor Kit 39.95 Technical Manual 24.95 with computer 9.95 RS-232 Computer Interface Kit 49.95 Advanced Software 49.95 onscreen display, stores to Lotus, Symphony, Windows(?), TSR Cable 50' 12.95 100' 22.95 150' 32.95 Saver Package Kit 599.85 weather computer, RS-232 interface, humidity and rain sensors also... Most Accurate Clock Kit 249.95 receives from NBS RS-232 Interface Kit 49.95 Software 24.95 IBM-PC weather card and software 299.95 includes boom assembly, monitors same things as weather computer above I know this isn't quite what you were after, but I woke up and couldn't get back to sleep. Even if you decide to build around your own microcontroller, you might find some of the sensors handy. Check out Heathkit at 1-800-253-0570. ------------------------------------------------------------------------- Kyler Laird I'm the NRA ky@en.ecn.purdue.edu