# Slot car track joy stick

Discussion in 'General Electronics Discussion' started by Ditchrat, Sep 24, 2012.

1. ### Ditchrat

4
0
Sep 24, 2012
Hello all, I was wondering if someone might help me with a project I have in mind. Please feel free to mention any issues that might need to be thought through. Admittedly I have little electronics experience past basic home wiring.

My three year old son has gotten into slot car racing (H.O scale), with me as a way to spend time together and as a way I can do arts and crafts projects with him, so I can transition him into being a DYI person as he grows up. So I did some basic wiring and hooked the lanes up on separate power supplies with regulated adjustable voltage so his cars stay on the track no matter how hard he pulls. Max is 22vdc 1a.

My next project it for myself. I thought it would be funny to add a "manual" transition concept to my lane.

I picked up a 4 position momentary on joy stick, with separate terminals for each switch. What I am wanting to is use the lead from the hand controller (70 ohm) and wire it up to each of the position. I'm looking to include resistors to 3 of the four position to limit the speed the car can go in each position. The fourth would be wide open when the controller was full depressed.

For the first 3 positions I am going to assume the controller would be in a 3/4 to fully depressed position, the fourth position no other resistance other then the controller.

My problem is I have no idea how to determine how much additional resistance I need to add to get the performance I am looking for.

My best guess is:
22vdc, 1amp available
Car draw about .25a running and .62-1a starting

Position 3 R=(22v-18v)/.25 R=16 ohm
Position 2 R=(22v-14v/.25 R=32 ohm
Position 1 R=(22v-10v/.62 R=19 ohm
Should I want to do this at 3/4 throttle I could simple subtract the measured resistance of the controller from the calculated resistance needed to determine the resistance wanted?

Thank you in advance for even taking the time to read this.

2. ### GreenGiant

842
6
Feb 9, 2012
it would be easier (in my opinion) to use voltage regulators, one for 10V, one for 14, and one for 18, or thereabouts, that way it will draw as much current as it needs at each range but you dont have to worry about potentially killing resistors (10V @ 1A = 10W... .thats a pretty expensive resistor, and large)

3. ### Ditchrat

4
0
Sep 24, 2012
I do happen to have some voltage regulators that I could use, looks like Ill go that route. Thanks