12-axis sensor adds auto screen orientation to this older tablet PC


[Mal'oo] has one of those laptop computers whose screen swivels to turn it into a tablet. But the thing is a few years old and didn’t come with an orientation sensor that changes the screen between landscape and desktop, but also knows which side is up. His solution was to add a 12-axis sensor via the mini PCI express header.

The hardware comes in two pieces. The first is a mini-PCIe card to USB interface. This is handy if you want to add a Bluetooth dongle permanently to your computer. But he’s got other things in mind for it. After hacking the BIOS (which for some reason limits what you can plug into this slot) he moved onto the second part which is a USB 12-axis sensor. This picture shows the wires before they were soldered to the USB card. [Mal'oo] couldn’t just plug it in because the sensor wouldn’t have been oriented correctly in relation to the computer. The final product is quite response, as shown in the clip after the jump. [Read more...]

Which way do non-polarized film capacitors go? There is an answer.


If you, like us, thought that capacitor orientation only matters for polarized varieties like electrolytic capacitors you should read through this article. [Bruce Trump] looks at why some film capacitors have a stripe printed on one end and why their orientation can matter.

He has an image rolled into his post showing both axial and dipped capacitors with a black stripe printed on one end of the package. This is an indicator of what is going on inside of the component. The end with the line has a conductive foil layer which acts as a shield. But it seems that this shield will do its job better if you do a better job of designing for the capacitor.

The diagram above shows two op-amp circuits, both using a non-polarized capacitor that will affect the circuit if it receives external interference. [Bruce] discusses various aspects of this phenomenon, mentioning that although these careful layouts can be tested in your designs to prove which has more benefits, simulated applications (using SPICE) will perform exactly the same.