CM17A versions - any difference?

In the BX24-AHT documentation you talk about cannibalizing the RF daughtercard from an X-10 universal remote. Would the CM17A yield a similarly useful RF transmitter?

-- Bobby G.

It depends on how hard you hit it with the hammer. ;)

Seriously, the RF transmitter in the CM17A is part of the main circuit board and not as readily accessible as those in the universal remotes.

What are you trying to do? I don't believe I ever implemented a way to drive an RF transmitter with the BX24-AHT. It was one of the things undone when I ran into memory constraints. As a matter of coincidence, I made a change to the roZetta design this morning that will allow using it's one free pin to drive an RF transmitter for things like ceiling fan control.

If you're talk>In the BX24-AHT documentation you talk about cannibalizing the RF

Yes - it was the latter usage I was considering. I don't have any X-10 universal remotes I want to cannibalize but I sure have lots of CM17A's!

-- Bobby G.

The skinnier CM17A is best then. You'll need to remove the PIC (or replace it with one of your own). X-10 uses the same RF transmitter design in all of their products (prior to the CM15A). You can find a schematic at the FCC site - look for one of your remotes. I know the one for the UR84A is there (your ATI remote). While it uses a SAW, the basic circuit is the same. You just need to supply +5V, GND & Signal.

You mean the little black flyspeck? (I finally opened it and was pretty surprised at how few components there were on the board.) I might be able to remove it if they shrank me down like the crew in "Fantastic Voyage" otherwise, it's very dubious.

So I can also pull one out of a TM-751? I have even more of those in the "butchered by Bobby box" than I do CM-17As!

I was interested in this mostly to find a way to use my wireless weather transmitters and log their data. The transmitters seem to be quite robust and their batteries last a long time. While it might be nice to also have a hard-wired temperature sensor net, there are times when the wireless version is quite useful. My wife uses them to keep watch over seed beds - the newest ones I have even have a temperature alert feature.

It's also made me wonder whether the best overall HA design would be autonomous units like the Oregon S's weather stations and Waterbugs reporting to a central HA PC and controllable from it, but able to operate independently of it if the need arises.

-- Bobby G.

No. The TM751 has an RF receiver daughterboard but no RF transmitter.

Since the RS/OS wireless protocol has been published I will try to design a module to allow their use with roZetta and with the ZX-24 version of the AHT. It will, however, have to wait and assumes that someone will loan me a wireless unit to experiment with.

I've always taken the approach that the devices need to operate independently of anything I design to monitor them. I just try to eavesdrop on the conversation between transmitters & receivers.

D'oh. I should have known that. It only talks to the powerline. My stupidity shows how much I really want to atone for my sins and find those poor, battered TM-751's a purpose in life. They were injured during an attempt to extend their range, which ought to give you another data point on my soldering skills. :-(

Considered them loaned. Do you want them now? If not, just remind me to send them when you're approaching that phase. That will prompt me to look into the Dallas temperature devices. As a humorous aside, when I first saw the assembled BX24-AHT I wondered why you had chosen such a non-standard battery size -- until I read the manual and discovered it was a Thermochron socket. :-) Neat. I still haven't powered it up yet - need to get to the RatShack and get a power supply and convert an old Pentium 90 into a test machine.

That's a lesson that's been beaten into me slowly.

-- Bobby G.

No, I've got plenty on my plate right now.

The DS1921 is one thing that never worked out. Initially it sold for about $12 and I thought it would be a good way to get a battery backed RTC with a

10-year life and a temperature probe all in one. Unfortunately, there were problems with early models and they stopped shipments. Once Maxim "fixed" it they doubled the price. I never got mine to work (which may have been my code) and decided it was not worth the effort at $25 a pop.

I have the Oregon S's weather station, and I am interested in capturing data from the wireless protocols to use with a HVAC control system. I wish to correlate Temp and humidity data with my solar PV system's 3 separate HVAC loads to best take advantage of my power utility's time of day rate structures. I have found that pre-cooling the house to lower temps than the normal desired temps will allow the HVAC to be turned off during the peak power use periods thus allowing me to export power during the time of day where my utility charges as much as $0.49 per kWh and to not use it myself. I do use the current temps and humidity to forecast the amount of pre-cooling needed as well as historical data previously captured from my weather station (3 years) and is then imported into a database for use in the prediction of hourly HVAC need.

Everyone I've attempted to get that wireless protocol from has either told me it was privileged info or just ignored my request. Robert, do you have a copy that you would be willing to email me? or maybe you do, Dave, in either case if somebody has it, a copy would be much appreciated. - Jim EMAIL without NOSPAM to me at snipped-for-privacy@NOSPAMbaber.org

I like your eavesdropping approach, it seems to be the least intrusive.

Jim Baber responded:

I appreciate the response, now I just need to understand it and try to implement something. I do understand your health issues and I am glad to see your continuing activity. I suffer with severe COPD and am on O2

24/7, and have to depend on others to do the simple things I wouldn't have even thought about 15 years ago.

Once I manage to get roZetta released (4-6 weeks) I need about 2 weeks to port the BX24-AHT code to the ZX-24 chip and another 2-3 weeks to update the BX-24 code for the BX24-AHT. Then I plan to write PIC code to handle the OS/RS protocol. It will be a DIY project to create a simple RF receiver with RS232 output that can interface with roZetta, the ZX24-AHT or BX24-AHT.

I'm still [snip]

Precooling is an excellent technique. I monitor humidity and temperature trends by eye and use strong ventilator fans to cool the basement and the attic in the cool summer nights. When I close up the house for A/C, it runs far less often that way, as you, too have discovered. There's so much potential for smart homes to save so much money we could reduce our dependence on foreign oil. I really admire your setup - and I see where automating those wireless thermometers will really be helpful in maximum your efficiencies.

Lets hope that both of you live long and prosper. COPD is real burden. I'm looking on Ebay for some oxygen bottle mounts for dad's scooter. The Feds would have paid $1200+ for a bottom-of the line scooter for him but I found a much nicer one on Ebay for less than $150.

[/rant on] I think as the baby boomers and the even newer generations age, they are going to demand power home windows, free air cooling and multiple fuel heating plants with heavy emphasis on solar. I need to automate my Dad's home front screen door. He gets bowled over sometimes when the screen door slams into him. I'd love to automate his windows but that's not going to be easy.

I would have given up on HA long ago as too complex and too unreliable but I am coming to understand that it's too indispensable to the physically challenged for me to give up on it. Anyone with any experience with residential storm door openers, please chime in!

I know that if I live long enough, I'll have a lot of the same problems as Dad so I'll need a lot of the same solutions. What I didn't understand until the "Ebay Scooter" project was how Mom and Dad reacted to their illnesses, withdrawing more and more from the world as it became harder and harder to move around in it. Today, in fact, I went out to my folks to fix a toilet, a blown antenna preamp and a faucet. Neither one of them had said that they had someone in to fix them, but they didn't do the job right. I wonder how many other elderly people just suffer in silence . . .

[/rant off]

-- Bobby G.

Just being able to turn the lights on and off from the bedside is a tremendous boon for many people with mobility issues. Tonight I'm going to mount a PalmPad to the arm of Dad's powerchair so he's always got some way to control the lights right at his fingertips.

-- Bobby G.