In short, I have a logic level circuit I need to switch.
I suppose a very small SPDT relay and small 2-3 second timer would do the job but it seems like there should be an easy enough way to do this with a couple of transistors and a 555.
After getting power it needs to wait to switch for 2 or 3 seconds.
I don't know how to make this work, but would really appreciate some guidance in making a solution for this problem.
I'm just kind of starting out with building electronics, so I thought this would be a good chance to learn something.
I attached a crude schematic of the current circuit I would like to automate.
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Long explanation for those who are interested in why.
I have a windows tablet pc that has only one micro USB port on it. It uses this port for charging as well as USB OTG to connect USB peripherals. The problem is it won't usually charge while in OTG mode. Just applying 5v to the power lines of the USB port won't make it charge.. To get it to charge, you have to short the data+/- lines together. Then as long as you keep power applied to the Power +/- lines it will continue to charge without shorting the data +/-. You can then connect usb devices to the data lines and the PC and they work.
Currently I am using a SPDT switch to accomplish this, but would like it to be automatic rather than having to flip a switch each time I plug in my tablet.
The purpose of this is so that I can charge the tablet and use USB devices at the same time. As it is now, I have to plug the usb hub in with the SPDT switch in shorted position and then flip the switch every time I connect the hub. I want to make it all automatic. It needs to have the lines shorted for a few seconds and then switch in the lines for the USB hub.
Detecting the USB plug in is easy, just use the USB shield and USB ground pin as a switch.. i.e. leave the ground wire disconnected in the USB cable. The shield wire is used to carry ground. When you plug it into the tablet pc it connects the shield to the GND wire (since they are tied together on the tablet's USB port) and completes the circuit.
Thanks in advance