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namtech
Joined: 10 Dec 2019 Posts: 1
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Make USB HID Device |
Posted: Tue Dec 10, 2019 1:53 am |
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Hi everyone,
I would like to ask a simple question for many people here.
I want to make usb hid device with pic18f2550 or pic18f4550.
how do I determine how many pot and buttons to use on the device
How do I determine pot values and sensitivities (example 1K or 5K)
do you have any friends who will explain all this to me with an example
I'm sorry for my bad english, thanks everyone |
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Ttelmah
Joined: 11 Mar 2010 Posts: 19496
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Posted: Tue Dec 10, 2019 2:01 am |
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That depends totally on what you want the device to do.
We can't design your device for you.
If you want real accuracy, so really fine resolution, then you need
to be using an external Vref for the ADC, and high quality ceramic
pots, possibly with op-amp buffers. However for a basic 'joystick' type
operations almost anything will do. It's all down to the performance
parameters your design involves. 'How many' again depends on how
many signals you want the device to give.
You need to start by working out 'what' you want the device to actually do. |
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temtronic
Joined: 01 Jul 2010 Posts: 9221 Location: Greensville,Ontario
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Posted: Tue Dec 10, 2019 6:46 am |
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As Mr. T says, there is a lot of basic design you have to do however consider replacing 'pot' with 'encoder'.
Pots suffer from 'noise' when the wiper scrapes of peces of the resistor. Classic example is a 'scratchy' volume control of a radio.
Encoders are optical so no 'noise'....every mouse has them, have for decades.
You can use them two ways, 1 - direct connection to PIC, so program has to read every movement or 2- a separate 'encoder chip', so the PIC just read the 'new data'.
Options.... always 'options', as the designer , you'll have to decide what's best for your project. |
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