Thread: EBY701 questions and opinions!!!!!!!!!

Originally Posted by triath5147

I realise this thread may be dead, but for anyone looking at this thread, I think you have all over engineered this answer. It is much easier, and much more reliable to use a solid state switch. You can make a solid state switch with a basic 555 timer board, and by using either changes in resistance or capacitance create a grounding or power trigger to match any second or millisecond count you so desire. If any one needs help with this you may contact me. Or respond to this post.
You can build a 555 timer circuit yourself very easily to suit a specific application, or you can buy 555 timer boards that you can adjust timing on them very cheaply. Just as an example based on this post.
The screen is changed via a momentary switch. To send a Momentary (+) signal to the Screen you would connect the 555 timer in parralel to the reverse light switch. When you go to reverse the signal would go to the 555 timer, and start it's count down. You can set the 555 timer to be a one shot timer. So what that means is. No matter how long your in reverse it will only send the momentary signal once, until the timer is reset. Once you leave reverse it can be set to trigger again and switch your monitor back to the other source. Than you don't have IR remote interference, or mechanical switch or relay problems. Also the 555 Timer works on milliamps of current, which is all you should need for a momentary switch circuit of a monitor anyway.
As far as the guy with the blue tooth thing, the same set up applies, and he could adjust the timer to emit a 2 second pulse. Hopes this helps people in the future. 555 timers are very low power, very easy to experiment with, very easy to unsterstand once you play with one. and are also very cheap and reliable.

Also something I forgot. Using a relay will give you voltage spikes that may damage sensitive electronic equipment. The 555 timer sends a square wave signal, that is spike free, and safer to use.

Its not a late reply.......... Anyways, what happens if the car is in reverse and the screen has not yet come on, like katit asked? Also will this 555 timer and solid state switch have to be moded to the board of the screen. Reason I ask is because when i attempted to soder directly onto the boards screen, the screen acted eratic. There is no interence for the IR, because the IR bulb is literally next to the IR sensor. The relay has a fuse and a regulator to prevent spikes so its safe........

Originally Posted by triath5147

As far as the screen not being on before you send the signal to go in reverse. It obviously would not work, but honestly I don't know what would work in that instance, as the screen would have to be on, to accept any signal to change to a different source. be it from a switch or ir transmittor or anything else.
As far as your regulator and fuse. You must have the voltage regulator and fuse on the switched side of the relay, not the coil side. The spike occurs because the points on the relay arc when they open and close, just like points on an old car ignition system, which is why they used a capacitor to lesson the spike so you didn't burn out your points.
So if your voltage regulator and fuse are not on the feed wires to the screen off of the relays contacts theya re not protecting your screen circuit.
As far as soldering to your monitor, the 555 timer is a solid state switch, they are not seperate. The 555 timer circuit can be built very small, like the size of a quarter, and can be installed anywhere in the car that is convienient, but it must have a wire that attaches to your screen board where the button is, which I assume you already have done anyway?

Yes I did try this and it causes all buttons to act as Source switch buttons..... The fuse and regulator are on the side that activates the switch, since a 12v signal from the reverse light is what triggers it (coil side). On the other side it simply attaches to the remote button simulating a button press.... Only power going through that is the 3v from the remote battery.

Originally Posted by triath5147

ALso as far as your other problem you need to use a diode to prevent feed back to the circuit board which is probably why they all acted like source buttons when you soldered to board.

Well the reason I actually have issues, is do to the way I decided to use the relay. Technically when it goes into reverse it holds the button down, then when it switches back it release for what ever milla second and then holds again. Because I am always holding the botton, which it was not designed to do, it gets all funky.

I just ran into another hurtle, which really sucks. The remote is powered by a 3 volt battery and because the relay is always pushing down the button, the remote had a dead battery, which I kinda knew would happen. Thankfully I have a 3v power supply which I am going to connect. It will turn on when the car turns on, along with the screen and camera, so by the time I go into reverse, it will be all good.

Depending on how you have your relay setup you may also want a diode across the coil of the relay to prevent voltage spikes. There are a couple threads about relay wiring and depending on what controls the relay it would be wise to add. May not be anything you need to worry about just an FYI.

Is there no way to mod the screen to switch the source input without a remote. It seems like the remote is an easy thing to play with but probably not the most reliable. Unless it had a VGA button and a Video1 button like you might see on a home tv remote.

Simpleest\Cleanest way i think would be a 10k ohm resistor from the tail light to a transistor to the selector pin on the screen itself. But you may only find the same functionality on the VGA screen circuit board. Where as it would only switch the source to the next one and not specificly to VGA or Video1.

Oh well, good luck with the remote. Post some pics of your wiring diagram if possible. May help us understand what your planning.


edit: looking at your picture made me think about it some more. if you dont need video2 then turn it off. use video1 and pc keep the rest of the settings. looks like the way you had it makes the monitor turn on and select pc by def (default) then you add a delayed pc on relay switch and a delayed turn pc off switch and tie it to the reverse light and wire it to a relay to trigger the monitors source selector switch . DONE! You can find schematics here on the forum ive seen a bunch of them. You use caps and resistors for timed delayed single pulse switches. Mostly used to turn your pc on or off when it sees the acc switch come on or off.

Hope that helped.

I think you guys are close with using the 555 to generate a pulse and make the monitor jump into and out of AV1, but here are a couple of my concerns:

1) Is the front panel button logic running at 12v or 5v? If it's 5v, you don't want to send it a 12v pulse from the 555. If it IS 5v, you'll have to run the 555 at that voltage. It's no big deal, since I believe the 555 can run from 5-15 volts supply voltage.

2) You'll need to think about the reverse switching a minute to make sure you get the pulse at the right moment. You need a pulse if you go from PARK to REVERSE and from REVERSE to PARK. You also need a pulse if you go from DRIVE to REVERSE and from REVERSE to DRIVE.
Example: I start the car and put it in reverse. I get a pulse and the monitor switches to AV1. I finish backing up and put it in drive. The monitor is still in AV1. How do I get the 2nd pulse to fire? The 555 will only trigger on a level transition. You'll only get one pulse as you pass thru reverse.

I like this idea, tho, and will have to give it some more thought. I just bought one of these monitors, so I've got something to fiddle with.