From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: Re: temperature sensor Date: Sat, 17 May 2008 02:59:17 -0400 Message-ID: <iqvs24t3oer0pjc62768g5ms6emol21mt7@4ax.com> On Fri, 16 May 2008 21:05:28 -0400, Steve Wolf <news@w8iz.com> wrote: >Among the most pervasive problem was when I bought a replacement clock >for the house that had a remote sensor. I set it all up expecting that >the home external sensor would give me the proper outside temperature. >Nope. It read 65 degrees, about five degrees higher than it should. Darn. > >A day or two later, it dawned on me that my daughter brought over a box >of miscellaneous stuff. Inside I found a temperature probe. BINGO! I >pulled the batteries and all should be well, right? Nope. Two days >later I went out to the motorhome and turned on the fridge in >anticipation of a trip. There it is! I keep a remote in the freezer >compartment. Pulled those batteries in that remote sensor. Nope. >Turned out to be the neighbor's sensor. I took my clock and sensor to >another location and got them all matched up. Brought it home and it >read ... nothing. Took it back to that same location without the sensor >and ... yep, someone somewhere had a sensor. I did finally get it >matched up but I'm still not convinced if it is to mine or my neighbor's. > >Yeah, wireless sucked. That doesn't happen with a wired device. Strange. I have two Accurites, one Atomix, one Lacrosse and a wireless grill thermometer and they all live in harmony. Of course, I understand how they work and carefully follow their instructions. All but the grill thermometer work the same so I bet they have the same chip inside. The grill thermometer works on a totally separate RF band and so doesn't enter the equation. This is how they work, confirmed by an email chat with a tech support dude at LaCrosse. When the indicator is powered up, it scans the channels for about 60 seconds. If nothing new is heard, it locks onto the strongest existing signal it hears. BUT! If, during that interval, a NEW transmitter is heard, it locks onto that one. The reason is simple. The instructions tell you to install the batteries in the indicator unit and then within about a minute, install the batteries in the sending unit. When the sending unit powers up, it selects a random channel. If it happens to land on a channel already in use as indicated by abnormal readings on the display unit, simply remove the batteries in both units for a few seconds and repeat. If you wait longer than the open listening period to install the sender batteries AND there are no other signals present, the display unit will usually lock on anyway and work properly. BUT! If you wait too long and your display unit hears your neighbor's sender, it'll lock onto that signal and ignore yours. The key is to follow the directions. I don't use a wireless unit in my RV because I consider the sender environment to be too hostile. Plus I dislike having to crawl on the ground to replace the sender batteries. John From: John De Armond Newsgroups: rec.outdoors.rv-travel Subject: Re: temperature sensor Date: Sat, 17 May 2008 02:40:27 -0400 Message-ID: <72vs241ftcm6f802277so2ajshirbafr0d@4ax.com> On Fri, 16 May 2008 17:19:59 -0400, "tim fm ct" <r.dolan@snet.net> wrote: >I've had a temperature sensor for outside temp reading while on the road. >The probe wire broke. I'd like to put in another outside sensor. >I've got a class A MH and I'm interested in ideas from the group regarding >the location of the probe so that engine temp doesn't effect it when not >moving. >Thanks in advance. > Tim fm CT That's a major problem, one that I've spent considerable time on. Keeping it away from the influence of the engine heat, the coach's heat AND the sun's heat is a challenge. I finally decided to copy what many car manufacturers are doing and locate the thermistor behind the front bumper. To isolate it from solar heat, I enclosed it in a double walled, white painted housing made from fruit juice cans that closely emulates the NWS's standard housing design. It is completely free from the influence of both the engine and generator heat except in the rare occasion when the wind is gentle but blowing just right. It is still slightly affected by sunlight, a degree or two, but I can live with that. I try to park with the sun at my back so I don't get awakened by the dawn light. If I ever take the thing out to rework it I'm going to include a little thermal mass to cause the reading to be averaged over a short interval. Probably a big blob of RTV. That worked nicely with my Maxxair fan's thermostat. http://www.neon-john.com/RV/Electrical/Maxx_air_mods/Maxx_aire_mods.html Photo toward the bottom of the page. John |