Complete noob - need guidance on a project idea

Projects General Guidance
1

I'm a complete noob when it comes to Arduino. I don't know a single thing about it so I'm hoping i can layout my project idea and someone can tell me if its possible and what its going to take.

I'm a bigtime modelrailroader and im in the middle of making my layout. I want to control my switches using servos which is a common and cheap alternative to something like tortoise machines.

Currently im controlling 8 switches with a system called [berret hills servo control base.](Base: Servo Control Base | Berrett Hill Shop) Its essentially a base board that controls servos. It has 8 ports, one side for servos and the other side is for custom sensor activated buttons with leds that activate the servos (touch toggles). The base has a controller you can connect to set the 2 different positions for the servo which is important.

I have about 30 more switches i need to control on my layout and with each base only controlling 8, i'll need a few more and their not cheap which leads me in pursuit of a more cost effective method.

I've come across the incorporation of Arduinos into model railroads before but for less "advanced" purposes.

After doing some research I've found that the Arduino mega can control 48 servos which is perfect and more than enough for me.

To keep this thread from being a whole harang ill cut straight the question.

Basically is there an easy way to use ardiuno to control servos for my model railroad? I need to control about 28 servos, all with 2 set positions. Im hoping that i can also continue using the touch toggles to control them which use a 3pin jst connector.

If i am able to do this, what would it entail? parts, coding, wiring, etc?

If anything needs clarification please ask as this would seriously help me out financially and progression wise on my layout. Thank you

2

Hahhhaa. The cool thing is, this forum is full of railroaders. Make your project happen one piece at a time.

Yes.

Draw a picture. Add to it as things come together.

3

Please show the datasheet for the servo You intend to use. That will help us calculate the need for power, amps, from the external power supply.
The number of Mega pins useful is hopefully correct.
Buttons toggling the swithes id hardware effective and easy to handle.

4

here is the item page with all the info. just scroll down

https://www.aliexpress.us/item/3256807857023974.html?spm=a2g0o.productlist.main.1.30c2fFUMfFUMFu&algo_pvid=84246e10-9a72-4466-9023-3cf5acc4f913&algo_exp_id=84246e10-9a72-4466-9023-3cf5acc4f913-0&pdp_ext_f={"order"%3A"29"%2C"eval"%3A"1"}&pdp_npi=4%40dis!USD!32.08!11.97!!!230.62!86.02!%40210337bc17471012633586493ed6f0!12000043395471170!sea!US!3012107515!X&curPageLogUid=mu6M0aIGPdkw&utparam-url=scene%3Asearch|query_from%3A

5

ard
ard978×798 85 KB

6

The stall current parameter is needed but it's missing in the data You reveal.

7

All sounds doable and although I have not searched I expect there might well be similar projects in the forum. The ‘related’ links directly below this thread could be useful initial reading.

I’m assuming the inputs deliver a 5V signal to the controller, either high or low going. So the coding would be simple and duplicated for each switch.

But doable for an absolute newcomer to Arduino could be a challenge.

8

While it can control enough servos for you it will not be able to power this many.

As others have said you need to know the stall current.

Also with that many servos banging about you will need to know about decoupling circuits. Read this for the lowdown on them:-
Decoupling Tutorial

9

"The SG90 micro servo motor has a stall current of approximately 650 mA at 6V, and 550 mA at 4.8V. This is the maximum current it can draw when it's locked or unable to move."

So somewhere between 550ma and 650ma?