Limit Switches/Pots

[Brett W]

Are there any specfic limit switches we should use or can we just go down to an electronics store and pick any ones we like. I also heard that we are only supposed to use 100K Pots with the control system or can we use any old Pot. such as a 10K Pot. Thanks.

[Josh Hambright]

as far as switches go... as long as they are available from digikey or one of the other approved electronics suppliers they are ok i believe. And on the pots it says somewhere in the manual that 100k (i think they are linear taper) pots are allowed. But then u can always use anything from digikey right?

If i get motivated later i'll look up the specific rule and post a better answer

[Lloyd Burns]

For OI and RC analog inputs, use 100 K only, linear taper, as specified in the FIRST Additional Hardware (The Robot, C-1) and the IFI RC manual, page 8, section 8. IFI doesn't mention the taper, but FIRST does.

There are two ways to read pots, one by charging a discharged, known capacitor through the pot, and counting the time it takes to reach a voltage, and you can pass a known current through it and read the voltage with an ADC. Both rely in one way or the other on the pot's resistance being in some known range.

But in your own circuits, use what you like.

Be prepared to buy good quality (eg, cernet type); you don't want the robot going haywire over a cheap one (eg something a large bargain retailer brought in) that wore out.

[Joe Ross]

unpowered switches are on the restricted parts list as any amount, any type. So you can go to your local electronics store and get as many as you like without it counting in the $200 electronics budget.

100k linear taper potentiometers are also on the restricted parts list as any amount.

You can use other switches or potentiometers, but you would need to buy them from digikey or FAI and they would count as part of the $200. You would also likely need to interface circuitry to get them to interface cleanly with the control system.