Hello,
First post here, but hopefully I've managed to cover everything!
Some quick background: I'm very much a dabbler in electronics. Trained as a mechanical engineer, and now working as a software programmer (LabVIEW). We're building a demonstrator project (a Stewart Platform), which will start off with 2DOF balance ball on the top. I'm using a National Instruments cRIO for the I/O.
I came across All About Circuits while searching for a 5 wire touch screen schematic. I did however managed to find a schematic for a 4 wire via this thread: https://forum.allaboutcircuits.com/threads/touch-screen-controller.13424/
I'm looking to make my own controller for the 5-wire touch screen for reading the ball position, as I want to see how quick we can read position feedback through the FPGA (i.e. I don't want to use a controller outputting position via i2c or some other communication method).
My initial thought was to use 8x n-channel Logic Level MOSFETs (I have spare TTL channels for control) to produce a voltage across the touch screen, and then read voltage back through an AI channel. Each corner would be attached to a MOSFET pair as per the attached schematic.
I'd drive the MOSFET gates with a delay between any change, to ensure we don't get any overlap (programmatically though the FPGA), but thought this would mean at some points in time it would be floating (?), so added a pull down resistor, to allow it to be connected to ground.
So to my actual questions:
Peter
First post here, but hopefully I've managed to cover everything!
Some quick background: I'm very much a dabbler in electronics. Trained as a mechanical engineer, and now working as a software programmer (LabVIEW). We're building a demonstrator project (a Stewart Platform), which will start off with 2DOF balance ball on the top. I'm using a National Instruments cRIO for the I/O.
I came across All About Circuits while searching for a 5 wire touch screen schematic. I did however managed to find a schematic for a 4 wire via this thread: https://forum.allaboutcircuits.com/threads/touch-screen-controller.13424/
I'm looking to make my own controller for the 5-wire touch screen for reading the ball position, as I want to see how quick we can read position feedback through the FPGA (i.e. I don't want to use a controller outputting position via i2c or some other communication method).
My initial thought was to use 8x n-channel Logic Level MOSFETs (I have spare TTL channels for control) to produce a voltage across the touch screen, and then read voltage back through an AI channel. Each corner would be attached to a MOSFET pair as per the attached schematic.
I'd drive the MOSFET gates with a delay between any change, to ensure we don't get any overlap (programmatically though the FPGA), but thought this would mean at some points in time it would be floating (?), so added a pull down resistor, to allow it to be connected to ground.
So to my actual questions:
- Am I totally barking up the wrong tree, or is the basic schematic attached how I should go about doing this?
- Should I just switch to a 4 wire, and use the schematic above? I picked a 5 wire, after reading they are typically more robust.
- Is there an alternative schematic I should be using instead?
Peter
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