timer

Connect a relay from the timer to pulse the remote's power button.

twice

Make/model of aircon?

Ken

Look for a programmable ("learning") IR remote control with a "timer" function. I've seen them in various brands for

Model a/c is Maytag 12000 btu, window installation with heat. Model number is in Florida,;I'm in Houston. Unit cost was $500.00, Home Depot.

This sounds like a "brillant" solution, but I have never heard of a timer on a programable remote. Give me a clue where to look for this item. TUVM Afterburner

The one I'm currently using is a "RCA Home Theater Universal Remote; 8-Device", Model RCU-810A. Cost US$50 at Best Buy in August, 2000. This is a "learning" remote with a lot more functions that you need for your AC; I'm sure there are simpler ones. In fact, I've seen TV adverts for a "remote for dummies" that has two large clock-style dials on it that can work TVs and VCRs even if "flashing

Best Buy, Circuit City, WalMart...etc. are likely to have similar current models. webpa

Thought I answered this question, but it didn't get on line: It's a Maytag 12000 Btu with heater, costs $500 at Home Depot. Serial number and unit is in Florida; I'm in Houston.

Tried to answer you by email, but no luck. When the A/C shuts down after the cycle it will not turn on again unless the start button on the pad is pushed or the remote is activated. I activate the remote with an AC electrical timer that closes a micro switch, mecanically, This switch closes the start circuit on the remote and the remote turns on the A/C. In about two hours the timer trips the microswitch and turns the A/C off. The microswitch is bolted to the timer and the little green and red nubs close and open the microswitch as the timer rotates. Not rocket science just a $5.00 timer and a $1.00 microswitch. Works fine except if the power goes out, it goes out of sync. Are you telling me that rcu-810A comes on automatically every day and would start and stop the Air conditioner functioning similar to the the electromechanical setup I have now? I tuvm for your comments.

--- Cute problem.

Sounds like if the AC mains go off while the AC is on for its 2 hour dehumidifying run and then the mains come back on before the remote issues the OFF pulse, the AC won't come back on immediately when the mains come back up, but will wait until it gets the OFF pulse from the rempte, which it will interpret as an ON pulse and then turn on and run until it gets the next pulse 22 hours later, go off for two hours and then go back on for 22, no?

As I see it, there are basically two routes you can take to arrive at a solution, the first being to put some smarts into the circuitry that's running the remote, and the second being to put some extra smarts into the AC itself. Since the AC is already wired to the mains and there needs to be some awareness of what the mains are doing/have done, I'd be tempted to start there insted of having to make the circuitry driving the remote mains-aware. But since you say the AC is a beast to work on, rigging the remote may well be the best way to go.

First, since you want something to keep time independently of what the mains is doing you'll need a (crystal-controlled?) timer that runs on batteries or runs off the mains and switches over to batteries in case of mains failure. If you use the switchover scheme you can make the batteries last for a _long_ time.

There are only five possible combinations of mains ON/OFF occurrences interacting with timer ON/OFF siganls, only two of which result in permanent ON/OFF time reversals:

First, normal operation:

____________________________________________ MAINS _ _ _ _ TIMER ____|1|_____|2|__________|1|_____|2|________ | | | | 22Hr -->||||||||||||||||

twice

The microchip website (manufacturers of PIC) has a technote on controlling IR remote controls. IIRC, it actually records the IR signal in eeprom, and plays it back when activated. Not a bad scheme, actually. Otherwise, you are stuck with analyzing the remote control protocol, which isn't too hard, its just a matter of determining which protocol it uses.

Also, there is a 'remote control' lamp controller design around that does the same thing (records, then replays the signal) using a PIC.

John, thank you so much for your imput. Your identification of the problum is "spot on!" The analysis does credit to your deductive skill. I have also done some analysis in the area of failure and determind the probability of failure at 8 per cent. I agree that the simplist way to solve the problem is a shunt on the on/off switch and a mechanical timer. The A/C is , as you say a beast to move, and requires three people to move because of its high location. Right now I am on hold, because I have located a timing devise that runs on two "C" batteries and turns water on to a garden hose and shuts it down at a specific interval. The inner workings are a small motor, gears, and a cut off switch. All this is controled by some regulating chip and other electronic parts. Problem is the one I have is defective and the manufacturer no longer makes a Nelson 5700 control valve. I planned to use the output to the motor to close a relay that closes the circuit and fires the remote. simple and easy. The Nelson company may have the parts, if they do: fine! If they don't I will look for another devise that operates similarly on battery power. For now I'm going to consentrate on Christmas and New Years. If I get the job done with this type of arrangement I will let all know, same if I don't!

Best to all of you on this New Year and a very grateful thanks!

Afterburner

What happens if you hold that button down when the unit is powered up by the timer? eg could you just fix that button down all the time?