Engineering Project - Simulator Controls

The project for my engineering masters is to re-do the control system on the university train simulator amongst other things.

One of the tasks in this requires me to create 2 dials for throttle and brake. These I have chosen to use potentiometers for.

Firstly, is arduino the best option for this? I have very little knowledge of microcontrollers and was curious about what arduino has over say the avr?

Secondly, when choosing my potentiometer, how important are the resistances and voltages? I have decided a wire wound potentiometer is a good choice as they have a long life span and mechanical feel, as well as a using a linear POT. But as far as the resistance and voltage ratings go, I have no idea.

Thanks for any help!

The project for my engineering masters is to re-do the control system on the university train simulator amongst other things.

We have no idea what that is or what it entails. Post the design criteria. Wire wound pots are higher quality and last longer. If it is equipment that needs accuracy or reliability or both they are a good choice. Be specific. List details.

Michael22: what arduino has over say the avr?

Most Arduinos are AVR- only the Due isn't if my memory serves, it's ARM. (I may be wrong).

The Arduino is merely a convenient packaging of an AVR on a nice board which brings the pins out, provides power, a few blinkenlights etc. and allows easy programming via the IDE.

Michael22: One of the tasks in this requires me to create 2 dials for throttle and brake. These I have chosen to use potentiometers for. Firstly, is arduino the best option for this? I have very little knowledge of microcontrollers and was curious about what arduino has over say the avr?

Any microcontroller with an ADC can read the value from a potentiometer. It is easy to do with an Arduino, and pretty much any potentiometer will be fine.

However I doubt very much if your project stops at connecting potentiometers to an Arduino. And as you have not told us what else is required it is almost impossible to give useful advice.

...R

Is it just me, or is anybody else scared by the fact that so many masters students are so inadequate at writing specs?

nilton61: Is it just me, or is anybody else scared by the fact that so many masters students are so inadequate at writing specs?

+5

And I would expect Masters students to be teaching us - not asking questions here.

...R

And I would expect Masters students to be teaching us - not asking questions here.

Does anyone know if their professors are posting for help ?

Well firstly, I am a mechanical engineering student and have done very little with regards to electronics and programming so less of a condescending attitude would be appreciated. If you want me to teach you about stress analysis of complex structures or dynamics about complex systems I would be more than happy to teach you and treat you with the same condescending attitude as Im sure you would know very little about something you have likely never learnt about.

Anyway, I have come on here to learn not to argue.

The controls are for a train simulator which is used for engineering human factors research, I am just trying to make the controls more realistic. There is very little with regards to criterea other than that, the controls are to talk to the Microsoft Train simulator software, I chose wire wound POTs due to their reliability and simplicity.

My question was mostly directed at the voltage ratings and resistances etc. of the POTs, I assumed that these would need to be matched to the arduino so thought the specs of my project would be irrelevant. As this doesnt seem to be the case, what information is required?

My post was not against you, but a general observation of masters students ability to write specs in a clear and concise way. One thing i consider being an essential skill no matter of discipline.

Michael22: My question was mostly directed at the voltage ratings and resistances etc. of the POTs, I assumed that these would need to be matched to the arduino so thought the specs of my project would be irrelevant. As this doesnt seem to be the case, what information is required?

If you just want to read a voltage set by the position of a potentiometer any Arduino and any pot will do. Just wire the wiper to the analog pin and one of the other pins to GND and the third pin to the 5v pin. The only constraint is it will work better if the the pot resistance does not exceed 10k.

I have no intention to be condescending. I am just surprised that any engineering course can get to a Masters level without a significant amount of "computer" content as they seem to feature in everything these days.

...R

Most things are monitored by computers but the mechanical aspects of most things are inherently still just that. People work in teams and as a result knowing all aspects of a product is not only unnecessary but would be very difficult. We have the option of learning robotics etc. on my course but I chose to go more down the dynamics and manufacturing route. There is so much that can be learned within engineering it would be impossible to cover everything within a 3 year degree.

So as I only need to measure the position of a dial, the requirements for the POT are quite vague?

I read somewhere that the power and voltage ratings were very important, does this not matter here as the power inputs are very low?

Just to clarify, there is no other components required within this circuit for the POT?

All other inputs required for the simulator are digital switches, I assume this is as simple as it sounds?

Your post, (no tolerance specifications (ie: % accuracy, Wattage, resistance )

Secondly, when choosing my potentiometer, how important are the resistances and voltages? I have decided a wire wound potentiometer is a good choice as they have a long life span and mechanical feel, as well as a using a linear POT. But as far as the resistance and voltage ratings go, I have no idea.

My Reply:

Wire wound pots are higher quality and last longer. If it is equipment that needs accuracy or reliability or both they are a good choice. Be specific. List details.

Did I answer your question about the pots ?

Just to clarify, there is no other components required within this circuit for the POT?

All other inputs required for the simulator are digital switches, I assume this is as simple as it sounds?

A pot (potentiometer) is a 3-terminal device . No other circuits are required.

I am not sure what you are getting at. Are you saying that this post is going to include a circuit diagram and other details, or did you just want to know if you should use wire wound pots ?

Have you , or have you not presented a complete summary of your project objective that includes all the hardware and any other details you need (ie: code) ?

Are you now going to introduce switches and code ? Why am I asking these questions ? The SOP here on the forum is:

1- the poster presents the project objective 2- lists parts involved (and any vendor links necessary for datasheets and specs) 3-posts schematics with component values and specs 4-posts code along with code criteria and objective 5- Explains his experience with electronics and code so we know how to phrase our replies.

Have you done all of the above ? (assuming your question was not the only one)

What we don't want is to be spoon fed a project one component at a time. (because it is a waste of time)

I apologise, I didnt realise there was a strict conduct with regards to what I can post.

I just wanted some advice on whether arduino was the best option, confirmation on my choice of potentiometer, and just making sure it really is as simple as adding a potentiometer to the ADC of the arduino (ie. there is no other components required).

The code etc. I am happy to work out myself.

It seems from your description that what is required is a robust pot.

Finding one with a suitable mechanical construction is I would suggest the biggest problem but you have not described that very well..

Trains to me imply big brass knobs on robust roller bearings.

The main parameter for pots is resistance (ohms).

Virtualy any value could be read by the arduino with ease.

But a typical starting value would be 10Kohms.

Another important thing is what does the train simulator do.

If there are large motors interference needs to be considered

One further point all the other inputs are digital so I assume that you are using the arduino to convert the pot to a digital signal.

There are other devices such as rotary encoders that do that anyway, they may be more appropriate than a pot for your use.

It is a simple static simulator, so no motors.

So if the resistance is important, what parameters do I use to choose a resistance? Or should I just pick any POT around 10K ohms?

Yes its to convert it to digital. But would I not still need a microcontroller for a digital input? Also Rotary Encoders dont have 'memory' do they? Are POTS not cheaper too?

Michael22: It is a simple static simulator, so no motors.

So if the resistance is important, what parameters do I use to choose a resistance? Or should I just pick any POT around 10K ohms?

Yes. But best method is to use it as a potential divider and measure the voltage not the resistance. Google will find examples.

Michael22: It is a simple static simulator, so no motors.

Yes its to convert it to digital. But would I not still need a microcontroller for a digital input? Also Rotary Encoders dont have 'memory' do they? Are POTS not cheaper too?

Encoders remember their last position its inherent in their design. I am talking about absolute position encoders here though not the pulse ones.

And by their nature the output is digital Yes pots are generally cheaper

http://uk.rs-online.com/web/p/mechanical-rotary-encoders/2632918/

Be aware of the mechanical life expectancy though.

use pots between 5000 and 50000 ohms the wiper to the analog input nd the ends to gnd and 5V

simple test int in=analogRead(ain); int out=map(in,0,1024,0,255); analogWrite(13,out);

now for a traincontroller: you will need a pot for MASS this will control acceleration/decelaration a power pot and a break pot use a transistor and a motor to simulate.

shooter: analogWrite(13,out);

You sure about that?

@jim yes