Go Down

Topic: feasability for arduino project (Read 1 time) previous topic - next topic

mapster076

I would like to use my new arduino to replace a handcontroller on our digital slot car circuit with the board keeping the last command given. Be grateful for any thoughts or comments on the feasability of this project.

Theres two parts to this project as I would like to control the car/board using the touchscreen on my netbook.

Heres a schema

[/img]

(In time I would like to be able to record the commands so the system is able to "drive" the car,with maybe a launch control and automatic pit stop, but lets not run before we can walk).

The digital system controller is slightly different to the normal pot type controller as it's a combined signal giving throttle and lane change information.

The throttle input is 10 stages with the values for each being;
0 - 0v
1- 0.72v
2- 0.92v
3- 1.16v
4- 1.32v
5- 1.72v
6- 2.02v
7- 2.36v
8- 2.72v
9- 3.0v

The lane change function is part of the input to the control system sending 2.6v if pressed and 1.3v if not pressed.

These seem to be well within the 5v output of the board.

Be grateful for any comments regarding going about this.

Thanks

Dave

Sacman

Your image isn't showing so not being a slot car guy, it is hard to picture the needed components. The only 'slot' car systems I have seen are like the Carrerra tracks or the smaller home systems. I assume you are talking about something bigger?

It sounds doable but I think more info might be needed. Is it a wireless system? Does the car actually run on those voltages or does it convert those to something else? Is there somewhere where we can see it in action like on YouTube or at least pictures of the system?
Luck,

Wade

mapster076

Sorry the image didnt show up.Think it was double IMG quotes



Hopefully this shows up.

Its not wireless although people are working on it, the track has a constant 18v feed and the 6 cars have seperate programed ids, its a not far from the DCC systems the train guys use, its called SCX Digital.

The voltages above tell the central control unit what speed signal to send to the car.   The system has loads of other functions, the throttle setting effects the fuel consumption, which in turn affects the accelaration. Once your car gets low on fuel, its starts to slow down and stutter then you need to head for the pits where the hand controller becomes a fueling system. 




DuaneB

Hi,
    Sounds like a nice project, I used to build slot cars from resin kits, never raced them though.

    One thing I used to have was a scalextric pace car system, It basically recorded your best lap then replayed it constantly so you could race another car against your own best lap.

    I still enjoy building the slot car kits but spend most of my time on RC Cars now.

    Duane B

rcarduino.blogspot.com

Read this
http://rcarduino.blogspot.com/2012/04/servo-problems-with-arduino-part-1.html
then watch this
http://rcarduino.blogspot.com/2012/04/servo-problems-part-2-demonstration.html

Rcarduino.blogspot.com

mapster076

#4
Feb 08, 2012, 10:07 pm Last Edit: Feb 09, 2012, 12:30 am by mapster076 Reason: 1
Thanks for the positive comments, I guess the ultimate aim is for the board to be able to control a "pace car" ,but I thought I ought to build my experience first, so

a) get the board to control the car at a constant speed.
b) work on the touch screen maybe have 11 areas to press, 10 for speed and 1 for lane change.
c) build on from there


First thought would be to connect the yellow wire from the diagram to the PWM port and the other 2 to inputs with black to one of the ground ports .

Then Im presuming I can use the LED dim program to control my throttle settings,

But I guess need to keep the 2 input signals in sync by alternating the input voltage ports over to the output port.

Any process improvements or thoughts welcome



Regards

Dave


Sacman

I found a youtube video where he is doing some of what you are talking about but he is still using a pot to control speed which you don't want to do.

http://www.youtube.com/watch?v=4moExVrvc44&feature=BFa&list=HL1328914451&lf=mh_lolz

So the trick then is to setup the serial from your netbook to control the variable output that is currently controlled by the pot.

It sounds like the feedback might be the trickier part.
Luck,

Wade

mapster076

Sacman

I kinda feel like I ought to write to the guy in the video and let him know about HO digital slotcar systems, but I guess he might have some chips lying about from his trains.

When you say feedback do you mean back EMF from the car motor, or interference from the other pins on the board (sorry Im not massively electronic yet, how ever reading arduino tutorials is radically altering that).

My thoughts after reading some of the tutorials is that my best bet is an analogue output port and configure the output to my motor step values.

Does this sound workable or am I going about it the wrong way.

Chagrin

If you're trying to duplicate the "digital hand controller" with an Arduino then yes it does sound like you're going the wrong way about this. I think what you're looking for is a digital potentiometer that can replicate the signal sent by the throttle.

mapster076

Bit lost here

Why do I need the digital pot, if I can get the 3v I need to drive the car from the board?

I guess Im missing something?


Chagrin

It's the difference between trying to replicate, with the Arduino, the Pitbox Control Unit or the Digital Hand Controller. From my perspective the latter seems more straightforward.

mapster076

Okay

Spent a bit of time understanding a digital pot today and the Ic protocol and its beginning to make sense.

One thing I think I might struggle with is how to work out which digital pot to use for my project as there seems to be hundreds on the farnell website.

Can anyone advise given the information above or will I need to move to a different thread

Thanks

Dave

mapster076

Is an AD5171 Digital Pot easy to setup, I was reading about the OTP and "blowing the fuse" to set the values,

Is this suiable for a novice?

Go Up