I like many of you have kids young kids. I have had the cheapo DVD players for a couple of years now and the wife says "I love these things" GREAT me to. It makes our long travels bearable We do not live in the city so every car ride is well a RIDE. Well now the age difference is setting in as one kid wants his show and the other wants his show. These players used to work great but over time cheap things will fail quickly. One player failed so now I have to send video from one player to the other so its a fight because one kid has to watch what the other is watching. I need a fix.

I would really like to keep it simple (2 portable dvd players) but I think that they will just break again.
Carputer sounds great (ala jonjandran) but to get two different feeds for two different movies.
Xbox (XBMC) but then again I would need to boxes.

It is just for kids so resolution is not a big deal. Anybody have any suggestions.

If the LCD screens are still working, then I'd basically buy a $35 power inverter and a couple of $20 Wal-Mart DVD players. Use the composite output on the DVD players to the LCDs and life goes on. Now the 4 year old can watch Spongebob while the 10 year old watches Harry Potter.

Yeah I had that idea and might just do it. Thanks. 4 year old Spongebob (you are correct) the 2.5 wants Diego.

This is probably a stretch but does anybody know of a small dvd player that has the inverter/power supply built in to go from 120 AC to 12V DC that way I could just open it and put in a cig lighter adpater instead of ramping up to 120 AC only to go back down to 12V DC long shot I know but thought I would ask. Hopefully that made sense.

like this kind of http://www.instructables.com/id/Digital_TV_Converter_Hack/

Actually, a large number of DVD players operate internally on 12VDC. A lot of the cheap ones even use the exact same transport from a PC DVD-ROM drive, which operates on 12V.

The problem though is that car voltage is nasty stuff. There's constant load dumps which mean power surges. It's not uncommon for the +12V in a car to actually jump to over 40V for an instant, before the voltage regulator can adjust.

For this reason, most car electronics are instead fitted with regulating and filtering mechanisms of their own. I've looked into doing this myself, but with a 50W inverter costing as little as it does, it was cheaper and more reliable than the parts needed to make my own regulator.

For the record, the parts that you will probably need:
16V Zener diode. This is for large surge protection.
63V 5,000uF capacitor (2) For filtering and regulation
Misc wire.

If the DVD drive also needs 5V, you can add in

LM7805 5V voltage regulator
N4004 diode
63V 220uF capacitor

Buying the parts for just 2 such, you can probably expect to spend about $25 to have them shipped from an online store, or about $22 if there's a deccent supply place nearby (Where prices are higher than on-line, but no shipping.)

When I compare that to a 75W Power inverter at Canadian Tire for $29.99 CAD, plus the trouble to build and test the thing... I'll just buy the inverter. 75W is more than enough to power 2 or 3 DVD players.

Supra thanks for the info. I did wonder about the voltage spikes in a vehicle. I popped open the small dvd player I had here and it does take the 12V and 5V just as you stated. Wouldn't the voltage spike just blow the fuse?

Would the internals of something like this help in the voltage spikes??

http://cgi.ebay.com/CAR-UNIVERSAL-LAPTOP-C...id=p3286.c0.m14

No, not really.

Those kind of power adapters don't do much in the way of power filtration and regulation. They depend on the target load (laptop, or whatever) having it's own on-board regulation. There might be some capacitance which will help smooth out transient spikes, but the general filtering of those things is not good.

Though the internals COULD be used to get you your regulated 5VDC though. Chances are that there's an LM317 voltage regulator in there with parts in place for the various regulated voltages.

Okay well then I guess the inverter will be fine. You really think a 75W one will run 2 dvd players? Like the one you posted? I guess all it really is doing is spinning the disc and outputting video so it shouldn't need that much power.

According to CE's energy consumption estimates (Data starts page 44, consumption data page 48) most DVD players seemed to draw between 8 and 10 watts while active, so yeah, I thin that 75W would be more than enough for 2 or 3 DVD players. It would probably also handle a recharger for a phone at the same time.

Yup the 2 I got only consume 10 watts so 2x10=20 (man that SupraGuy is smart we should listen to him more often) I threw it all in there and it works just fine. ONE problem! I knew about this problem when I bought the players. Since they make them as cheap as possible the actual players do not have skip or reverse on them it all has to be done with the remote. So when I use the remote obviously I am changing one kids movie when the other doesn't want it changed. I guess the only way to remedy this is to find another small player that doesnt use the same code for the remote control. ARRRRRR Anway just throwing this out there in case anybody finds my dilema amusing.

LOL that reminds me of a tinme when i was a satelite engineer a customers cheap pos stereo used the same frequency as the box remote so i was sitting there trying to setup the tv while at the same time the sterio is coming on / off /changing track etc i'm sat there thinking wtf!??

Good to see you got it all working though are they installed perminently? if so got any pics of the install?

Is anything really permanent that involves kids? But yeah its all installed I tried to hide the wires as best as possible. Everything would have worked out great but the dang buttons on the player. I need to find some small dvd players like the size of a discman. Anybody have any ideas or model numbers?

1. disassemble remote control
2. remove IR LED. Solder in 2 conductors to the LED output.
3. disassemble front panel in DVD player.
4. solder in 10k Ohm resistor and connect to the wires from the remote.

You now have a WIRED remote which will operate that DVD player and not the other one.

If you're clever, make it a 4 wire bus and take your 3VDC from the DVD player, too, so the remote never needs batteries. Bonus! You don't have to leave batteries in the stinking hot car for them to overheat and explode.

Note: The 100 ohm resistor may need to be a different value. I'd PROBABLY check the specs for the photosensor for it's voltage output and then work out the needed resistor based on a 3V input to the IR LED. These are typically 1V or so, and the circuit has about a 500-1000 ohm resistance. If you have the parts around, maybe start at 10K and work down until the remote functions properly as you expect.

SERIOUSLY is there anything you don't know? I didn't know you could do that. But you totally lost me on the resistor part

I don't claim to know everything, lots that I learn all the time.

Okay, basically it works like this... (Starting from the basics, which you may not need, but perhaps others who are thinking of the same thing will.)

The remote control sends a modulated signal to the IR LED, which in turn turns into a modulated signal in light. The signal that it sends to the LED must be of a minimum voltage, or else the LED won't light. This is most likely the battery voltage, which is somewhere between 2.4 and 3V (Depending on if you're using rechargeable batteries or not.)

The IR sensor in the DVD player picks up this signal, and generates a voltage which is then picked up and translated. The IR sensor will NOT be generating 2-3V, more like 0.3V, but you really ought to look at the datasheet for the part that you actually find. The resistor is to "drop" the voltage from the remote somewhat to match what the receiver is expecting. Even if it's expecting a higher voltage (Some do) you'll want a bit of resistance on the circuit to protect it. Oh, and in retrospect, I should have put the resistor in the remote control, to protect that end from a short circuit, in case the cord is damaged.

So, in essence, what happens is an electrical signal is converted to light, and then back to an electrical signal. We're just skipping the middle step, and sending the electrical signal directly, with no conversion to light and back.

As a bonus, the one in my cheapo DVD player (Which the IR LED died in my remote) was also fed 3.3V power, so I just grabbed that to feed the remote, no more batteries. It also occurs to me that this also meant that the remote is no longer electrically isolated from the DVD player, which was probably also a good thing, in terms of signal transmission. (I might have been able to get away with a 3 wire cord instead of a 4 wire cord. Well, since I used a telephone cord, I had the 4 wires anyway...)

It's not necessarily easy, but since I figured that I was risking a whopping $19.97 DVD player, it was worthwhile.

Some potential "gotchas"

The signal is polarity sensitive, so the wire has to go the right way.

Okay this is starting to make sense, and its quite interesting or maybe I am easily amused. Thanks again for all your help. Would I be able to measure the voltage on the remote with a meter to get the correct value and the correct polarity? I am sure I could find out the polarity just by looking at the IR Led.

For the LED, yes, On the receiving end, you're going to need the datasheet for the part, but the part number will be on it, and Google is your friend. The IR receiver should need at least 3 pins, and possibly 4. (Mine had 4.) +VE (power) GND (Ground) and Out (signal.) Possibly there will also be a signal ground, which mine had as well. I had a bunch of RJ60 jacks lying around so I cut those into the case and remote with a soldering gun. They let me connect a telephone cable between the DVD and the remote, so the remote is wired. Becasue it's an easy task, I can also change to a shorter or longer cord as needed. I currently have a 6' cord on, because it was lying around, but I've been meaning to make up a shorter one, since I don't need the range. (This also means that I've stopped losing the remote. )

If you can't find the datasheet for the IR sensor, you can find what you need using a multimeter.

1. Remove the IR LED from the remote. (You were doing this anyway.)
2. Remove the IR sensor from the DVD player.
3. Look at the PCB where the IR sensor goes. It ought to be labelled for +VE and GND anyway. Use your multimeter (Unit plugged in, powered off) to check for voltage. This is the IR receiver's required voltage supply.
4. Use batteries to power the IR receiver up Probably going to the closest multiple of 1.5V is going to be fine If it's 5V for example, 4.5V (3 batteries) will be good, but if you're using rechargeables, then use 4 to get 4.8V. Use 2 more batteries to provide 3V to the IR LED. 2.4V will also do for this.
5. Point the IR LED at the receiver and measure the voltage on the output. Turn off the IR LED and verify 0V when there's nothing. (Be sure that there aren't other IR sources active)

Best case scenario, your part gets fed between 2.5 and 4V, and you get a 2-3V signal out. This means that you can basically just wire the LED to the receiver, and power the transmitter off of the power feed.

Most likely the signal voltage will be lower, in which case a simple resistor will do the trick to bring down the LED voltage.