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Topic: Help with layout on first scale model. (WITH PICS) (Read 3184 times) previous topic - next topic


Jun 27, 2013, 02:28 am Last Edit: Jun 28, 2013, 12:02 am by tjrusk12 Reason: 1
Hi! I have constructed a scale model car wash and plan on buying the Arduino UNO R3 with a breadboard, relay boards, and other small parts to make the model fully automatic. I am new to micro controllers and programming with code. So please help!  :) I plan on using the Arduino to send short output signals to the relays on the breadboard. The relays will activate the washer motors on the car wash. My question is, how do I layout the relays and the Arduino for five motors? Also, when I'm programming, I need the Arduino to send multiple output signals from different ports on the board, to the different relays at the same time. How could I code this? Any advice will work. Thank you so much! :)


The Arduino can only do one thing at a time, but the 'things' usually only take microseconds. Unless you're worried about one motor starting a couple of microseconds after another, they will appear to have started at the same time.

What are the specs of your motors? They may not need to be controlled by relays.
Do they need to be reversed? Do they actually pump suds and water?

And, just out of curiosity, what scale is your model? :)


Ok! Thanks for your reply! Exactly how do I program it to do this? The machine itself is supposed to move back on a track to a certain point, stop, then spin the brushes and pull the arms in to wash the back of the model car. I hope I making sense to you. Lol. So basically, I need the Arduino to send signals to the relays to start the washer motors. Then a couple seconds after I need the Arduino to send signals to the servos to move the arms in. So, is this possible?

The washer motors are around 120rpm, they are 6v DC and they are a little smaller than a thumb. It would be nice if they could be reversed, but if it requires many parts than I probably won't reverse them. BUT, the motors to drive the machine along the track have to be reversed. There is not any soap or water on this model. So no.

I'm not sure of the scale, but the frame is about 2-1/2 feet in width and about a foot tall. Thank so much for your help! The picture below shows one of the arms with the brush, and also the servo controlling the arm.   :)


Your project sounds like it is very well within the capabilities of an Arduino Uno. I'm less sure about your capabilities to conceive the solution and write the code.

An Arduino has functions to operate servos and to make motors run at different speeds. However an Arduino is almost certainly unable to power the motors or the servos. You can get a "motor shield" (which I haven't used) that makes connecting motors easy or you can use a few transistors to interface between the Arduino and the motor power if the Motor Shield seems too expensive.

That should give you some pointers about what to study in the extensive Arduino documentation. There are probably few Arduino problems for which Google has no answer.

Two or three hours spent thinking and reading documentation solves most programming problems.


Ok. Do I need to look at classes or something for writing code? I'm not sure how I will get the Arduino code to handle all of these tasks.

I'm having a separate power supply for the motors. That way the Arduino doesn't mess up. I know it can't handle the power supply for the motors, so I'm having a separate power supply. :)


I'd suggest that you simulate your system using LEDs to start with. Get some LEDs (and current limiting resistors) and some switches and do some of the tutorials getting the hang of reading digital inputs and turning leds on and off. Build up to an arrangement where the LEDs simulate your motors and gradually introduce the servos and real motors.

Be careful that you don't attach/power anything directly from the arduino that needs much current or you may find yourself purchasing another Uno.


I know it can't handle the power supply for the motors,

It also can't directly control the motors either, you will need transistors or as has been mentioned relays.

Rob Gray aka the GRAYnomad www.robgray.com


Than you all for the replies! wildbill that is a smart idea, ill do that. ok!  :D
ok so make sure this sounds right, for the final layout (after i learn how to do the basics of the arduino and coding) i want to have a breadboard. the breadboard will feature a power supply for the motors. Do i need a seperate one for the servos too? the relays, or transistors, whatever is best, will be connected to the motors as a switch.
also, if i use relays, will i have to send a continous output signal to the relay to keep it switched on, or do the relays just need one little signal and they open? sorry if this is an obvious question, im still kinda new to this. :) thanks


As long as it has enough amps and the right voltage the one power supply will do for everything.

The Arduino has a simple means to control the speed of motors using PWM (pulse width modulation). It may sound complicated but the Arduino does all the complex stuff. To use this you will need to use transistors rather than relays between the Arduino and the motor.

Relays would only be useful if you are happy for the motor to be either full-on or off. Most relays need a continuous signal to keep them on but you can get latching relays.

Two or three hours spent thinking and reading documentation solves most programming problems.


ok. sounds great. thanks so much.
well i want all of the motors to be full power, so a relay will probably work best. i was thinking about getting five of these relays, but i dont know if i need a transistor. or if i would need anything additional to get the relays to work. http://www.pololu.com/catalog/product/2480

how do i program the arduino to send multiple continous signals at the same time? i also need the arduino to control the servos at the same time its sending those signals too. is this possible?


I think it may be time for a little study and thought.

Why do you think the Arduino couldn't "send multiple continous signals at the same time? i also need the arduino to control the servos at the same time its sending those signals too." ?

Two or three hours spent thinking and reading documentation solves most programming problems.


Actually, i just finished studying up on it. And i finally figured it out! :) thanks so much for your help.  ;)


Ok, so these are a couple pics of my model car wash. I plan on using the Arduino to make the model run back and forth on a track, turning the washers and controlling the arms. If this was your project, how would you wire this and do you have any suggestions? I plan on using a breadboard, relays, and transistors and other required parts to run everything.


As you're new to this, you're not likely to get this going on your first try, so counter intuitive as it seems, it's probably not worth planning this out in detail at this stage - things will evolve.

Once you've got some basic arduino proficiency, pick an aspect of your system and experiment with it. Servos are probably the easiest. Write sketches that control a servo, preferably detached from your model. Work up to a sketch that moves your arms correctly. Then add your motors. Then some limit switches on the track, etc etc.

Your model looks quite sturdy, but I expect it will cause vibration. Tracking down loosened connections on the breadboard will be annoying - once you have the circuitry down, consider soldering your control board up in a more permanent fashion.


Thanks for your advice! i will definently try this. :)
i would like to keep the breadboard non soldered so i can change it around if necessary. but i will see what i need to do when i get to that point. :)

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