Announcement

Collapse
No announcement yet.

OT, DVD player remote controls.....

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • OT, DVD player remote controls.....

    Yes, quite OT but I am sure some here may know the answer.

    We have a dozen or so DVD players around the exhibits in our little aviation museum and it is a real pain starting them all when the museum opens.

    As you might expect these exhibits are in a hangar type building and my basic idea is to put 'something' in the roof of the hangar that will start the DVD players. We have two types of player only (until someone gives us another, ha ha).

    Can we put some sort of infra red floodlight in the rafters and modulate it with a PC to start all the players? What would the 'floodlight' be?

    Alternatively could we run a wire pair around the hangar with IR diodes near the individual players and drive that with a PC?

    We do have some software capability but first I would have to learn the format of the control codes.
    Last edited by The Artful Bodger; 11-15-2011, 09:05 PM.

  • #2
    Yes and no. The problem is that each player is going to have a different IR code for all the functions. Often the codes for a specific brand will be the same between models though.

    Look at a tv-b-gone. It is a little device that outputs all the tv off codes it knows to turn any TV off. You could do this with the play command instead.

    http://www.ladyada.net/make/tvbgone/faq.html

    Comment


    • #3
      There is a remote extender product that takes the input from the hand remote, then re-transmits it through an IR led which you place where it is needed. If the remotes for the two types of DVD player you have don't interfere, then you could wire up a loop of IR emitters to cover all the machines, then feed the loop from a module that sits on your desk.

      I've only ever seen these where they power a single emitter led. It's designed to be used where your remote can't shine through walls or closed cabinet doors, etc to operate the equipment. With some electronics knowledge, you could replace the emitter with an opto-isolator and use the output stage in that to run a string of emitters from a higher voltage power supply. IR leds have a fairly low voltage drop, around 2 v or so, so you could run 4 to 6 of them in series with only a 12v adapter as a power source. You could run two or more strings of emitters in parallel, depending on the current rating of the output side of the opto-isolator.

      Come to think of it, you could go into the hand remote itself and remove the emitter, replacing it with the opto-isolator. The remote would now be 'wired', but it would stay at the station anyway so that shouldn't be a big deal. The station would just be a place where the adapter wires come together with the output side of the isolator and the wires leading off to the emitter strings. Maybe a resistor or two in there as well.
      Last edited by darryl; 11-16-2011, 01:49 AM.
      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

      Comment


      • #4
        Thanks Darryl, I had something like that in mind as a second preference but I was really hoping there is some way I could flood the whole hangar with IR as we do move the exhibits quite a bit and it would be really neat to not have to run wires to each position.

        Comment


        • #5
          Check out the sequence needed by using a photo diode connected to an oscillocope. The remote signal is a simple pulse width modulated on/off sequence superposed on a 38 khz carrier.

          Make an aluminum disk 40 cm in diameter and cut 800 equally spaced slots around the circumference perhaps 5 cm deep. If this is mounted on the shaft of a single phase 50 hz 2 pole induction motor and placed in the path of the light from quartz halogen bulb it will produce a 38 khz carrier. If that is followed by another disc with the correct pattern of slots to modulate that carrier with correct code it should be able to control everything in the space easily.

          Of course, you could just use a 3 watt IR LED module from DX and modulate it appropriately. A 555 timer can provide the carrier through a power FET and the PWM pattern can be made with several shift registers in series that are preloaded with the correct bit sequence and shifted out to modulate the supply to the power FET.
          Free software for calculating bolt circles and similar: Click Here

          Comment


          • #6
            You could flood the hangar with IR- all it takes is some power. Like Evan suggested, use a much more powerful emitter, or maybe three. I wonder what effect there will be on peoples eyes? After all, if you look into even a typical modern white led you are repelled by the intensity. Just because you can't see IR doesn't mean it won't be harmful to some extent. I think you'd want to spread the intensity over at least three emitters anyway.
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

            Comment


            • #7
              Hanging up in the rafters it won't be a problem at all. All it takes is a few watts. Inverse square will do the job well.
              Free software for calculating bolt circles and similar: Click Here

              Comment


              • #8
                Evan, although the Nipkow disk is very attractive I wonder what the other guys would have to say about it? Certainly an interesting avenue especially if I can get an electronic 'shutter' to key the beam, are LCDs useable as a shutter?

                Darryl, yes, multiple roof space emitters would be easy enough and would be a good idea for the reasons you mentioned.


                Regarding modulating the emitter I am assuming that I can use an IR receiver with an amplifier to drive the emitter. If I do that we can use the remote(s) and there will not be need for any changes if we get any other brands of DVD players. Does that compute?

                Thanks for your contributions...

                Comment


                • #9
                  LCD are fine as shutters. They are used in the Nvidia stereo glasses for 3D computer display. The main problem if used with a quartz halogen lamp might be heat. Driving LCD shutters is a bit fussy. They must be driven by a pure ac signal. Even the slightest amount of DC offset will destroy the LCD. You could however combine the ideas and use a 555 timer 38khz modulated IR source with an easy to make disk for for imposing the PWM pattern on the IR carrier. The timings are not critical. The spec requires only +/- 10% accuracy.
                  Free software for calculating bolt circles and similar: Click Here

                  Comment


                  • #10
                    get an atc cadet to come in earlier , start all the dvds and put the jug on, the old fashioned way!!!
                    My neighbours diary says I have boundary issues

                    Comment


                    • #11
                      You could probably get lucky and take an IR detector out of an old vcr and drive a transistor with it. A suitable transistor with enough current capability would be easy to find to drive a few emitters in series. It would be a simple circuit anyway, and not that critical as you'd most likely have your hand remotes very close to the detector. A couple resistors, the detector, the transistor- the rest is wiring.

                      I got lucky once and found a solar cell that would respond to IR. I used it to drive a meter directly simply to check for remote function. A pair of resistors would be set up as a voltage divider to set the base voltage on a transistor at about .5 volt, then the solar cell goes between the junction of the resistors and the base of the transistor. Any output from the cell would cause the transistor to conduct. You're looking at a circuit with about five parts altogether, not counting the power pack or mechanical things. The easiest way is to use a solar cell because it generates its own power from the influx of energy, and this power turns the transistor on directly. I had to shield my cell from ambient light so it would only respond to the remote under test.

                      I tried to make another one of these remote testers using a solar cell from a dollar store calculator. It didn't work, in part because those cells have a hard time generating even a fraction of a milliamp- you would have to use a cell that is actually meant to produce several milliamps or more. I'm not sure on this, but I think the polycrystalline cells would be the ones to use, not the amorphous ones. Evan can probably suggest the proper type to use. Seems to me if they are not saturated with wide spectrum light, they will be fast enough.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                      Comment


                      • #12
                        Originally posted by Yow Ling
                        get an atc cadet to come in earlier , start all the dvds and put the jug on, the old fashioned way!!!

                        Nice idea, but we are open every day now and some days the sprogs are supposed to be in school!

                        Comment


                        • #13
                          Originally posted by darryl
                          You could probably get lucky and take an IR detector out of an old vcr and drive a transistor with it. A suitable transistor with enough current capability would be easy to find to drive a few emitters in series. It would be a simple circuit anyway, and not that critical as you'd most likely have your hand remotes very close to the detector. A couple resistors, the detector, the transistor- the rest is wiring.

                          I got lucky once and found a solar cell that would respond to IR. I used it to drive a meter directly simply to check for remote function. A pair of resistors would be set up as a voltage divider to set the base voltage on a transistor at about .5 volt, then the solar cell goes between the junction of the resistors and the base of the transistor. Any output from the cell would cause the transistor to conduct. You're looking at a circuit with about five parts altogether, not counting the power pack or mechanical things. The easiest way is to use a solar cell because it generates its own power from the influx of energy, and this power turns the transistor on directly. I had to shield my cell from ambient light so it would only respond to the remote under test.

                          I tried to make another one of these remote testers using a solar cell from a dollar store calculator. It didn't work, in part because those cells have a hard time generating even a fraction of a milliamp- you would have to use a cell that is actually meant to produce several milliamps or more. I'm not sure on this, but I think the polycrystalline cells would be the ones to use, not the amorphous ones. Evan can probably suggest the proper type to use. Seems to me if they are not saturated with wide spectrum light, they will be fast enough.

                          Would an LDR respond to IR and would it be fast enough? I have a few opto interrupters, surely the receiver part of them must be OK for IR?

                          Otherwise, solar cells, those ones they make for solar powered garden lights must have a useful output.

                          I guess there are a number of ways to go if I am to put a string of emitters around the rafters.

                          Comment


                          • #14
                            Originally posted by Evan
                            LCD are fine as shutters. They are used in the Nvidia stereo glasses for 3D computer display. The main problem if used with a quartz halogen lamp might be heat. Driving LCD shutters is a bit fussy. They must be driven by a pure ac signal. Even the slightest amount of DC offset will destroy the LCD. You could however combine the ideas and use a 555 timer 38khz modulated IR source with an easy to make disk for for imposing the PWM pattern on the IR carrier. The timings are not critical. The spec requires only +/- 10% accuracy.

                            Hmmmm, LCDs sound a bit tricky, what is the baud rate of the data that is modulated onto the 38khz? I am thinking maybe I could put a shutter, or a mirror, on a solenoid if the baudrate is low.

                            A spinning disk and a QH lamp does sort of fit in with my reputation around here!

                            Comment


                            • #15
                              You should look into using the Arduino platform for this, check out the Arduino micro-controller: http://www.adafruit.com/products/50

                              you can also get wide field IR led's from here:

                              http://www.ledtronics.com/Products/P...x?WP=1737#1745

                              It would be a simple program and device.

                              Comment

                              Working...
                              X