Thread: My solution to Auto Power ON Lilliput screen

Also, as a quick FYI for those with other lilliputs, this mod should work with a bit of research. From the little board with all the buttons on it, where the ribbon cable connects to, you just need to trace back some connections:

1) Main power - the thick tracks on the board, it will also connect to one side of the power button
2) Power button
3) Power LED

These three points will trace back to the ribbon connector, then map that back to the main PCB. The mod gets +5v from the LED connection (one end of the 150K resistor) and then the other end attached to the + side of the capacitor which also attaches to the trace for the power button. This is where you're supposed to remove the existing surface mount resistor. Then connect the - side of the capacitor.

FYI: This mod is not needed anymore: Lilliput Programming Guide, More Reset Codes

it is if u screwed up ur cable like me

Originally Posted by TO_SC300

Also, as a quick FYI for those with other lilliputs, this mod should work with a bit of research. From the little board with all the buttons on it, where the ribbon cable connects to, you just need to trace back some connections:

1) Main power - the thick tracks on the board, it will also connect to one side of the power button
2) Power button
3) Power LED

These three points will trace back to the ribbon connector, then map that back to the main PCB. The mod gets +5v from the LED connection (one end of the 150K resistor) and then the other end attached to the + side of the capacitor which also attaches to the trace for the power button. This is where you're supposed to remove the existing surface mount resistor. Then connect the - side of the capacitor.

i wanted to go the way of just using the 100uF cap and no resistor, how do i go about that, do i need to remove anything or just attach one side of the cap to ground and the other to that point on the main pcb?

I have a 10.4 touchscreen from Dynamix Computers. My problem is that the same button that turns it on, also switches between the 3 video inputs. I pulled a lead from the UC side of the existing power button, and hooked it to one side of a momentary switch, with the other side to ground. I just push this button to turn the screen on. No, in my install, the 'factory' button was not accessible.

So, I was thinking...could I build a circuit like this one, and make it external, on the wire I brought out? Where this circuit has 5v, mine would have 12 (vehicle power). Also, with my monitor, if you hold the button too long, it will switch to the other inputs, and eventually off. Just about 1 second seems to be about right. Varying the capacitor and resistor values would fix that.

Problem is, I've just exceeded my electronics knowledge. Anyone want to start me in the right direction with component values? Please??

Toby J.

Originally Posted by Because

I have a 10.4 touchscreen from Dynamix Computers. My problem is that the same button that turns it on, also switches between the 3 video inputs. I pulled a lead from the UC side of the existing power button, and hooked it to one side of a momentary switch, with the other side to ground. I just push this button to turn the screen on. No, in my install, the 'factory' button was not accessible.

So, I was thinking...could I build a circuit like this one, and make it external, on the wire I brought out? Where this circuit has 5v, mine would have 12 (vehicle power). Also, with my monitor, if you hold the button too long, it will switch to the other inputs, and eventually off. Just about 1 second seems to be about right. Varying the capacitor and resistor values would fix that.

Problem is, I've just exceeded my electronics knowledge. Anyone want to start me in the right direction with component values? Please??

Toby J.

I am not sure if the Lilliput solution will work for you but this is another solution that will work. Constant to momentary circuit.

From the12Volts relay page

Base on that circuit. Tap 2 wire from the power button 2 pins and connect to the relay pin 87 and 30

There are some similar circuit posted in the hardware dev forum sticky post "diagram, schematic ... " as well.

Great stuff...thanks!

If I put a ground on pin 87, instead of 12v, it will give me the momentary ground I need to fire my monitor.

Thanks again...

Toby

I've used the above circuit to "push the power button" on my carputer. When it received the +12V ACC the circuit would engage for about a second and then stop thereby simulating pushing the power button.

It made it easier than manually starting the computer which was behind my back seat at the time. I did not want to run a switch to the front of the car because I wanted it to automatically turn on and I did not have my OPUS yet (which will get installed when I get back from Iraq).

Derek

I also have a dynamix screen that has a common power and source button.

I have found that powering it on, and then holding the power switch down for 4 seconds will turn it on.

Can anyone take a swing at what value capacitor should be used to give a momentary on of ~4 seconds?

I do not think it is as simple as assuming since a 1k uF cap gives you 1/2 second, that 8k uF will give you 4 seconds, right?

Thanks