Creating an automated super crane

Hello,

I have a crane like this: https://www.aliexpress.com/item/For-2016-Children-s-Chirstmas-Gifts-Strange-Wire-Control-Construction-Tower-Crane-Toys-Simulation-Model-Educational/32753578995.html?spm=2114.search0302.4.6.AOghqE

With an arduino mega and some relay I would like to make it automated. For example: - 5 sec up - 3 sec turning left - 5 sec down etc.

Can you help me to choose the right relay? Is this one could work? https://www.sainsmart.com/products/4-channel-5v-relay-module

thank you for your help

Those relays should be fine. But you have not told us how you propose to use the relays and relays may not the the best solution.

If you want to drive motors then using motor driver modules that allow for speed control might be a better option. (Pololu is just one of many suppliers).

…R

Hello,

My idea is using the same logic as in the controller of the crane -> "connecting" the wires if I want to move up, and connect the other to wires if I want to move down. The sam with turning.

Using a motordriver: When I measured the Volage of the wire (during use) it was 2,5V. Can you suggest me a cheap way to control a motor like this?

Thank you very much!

Measuring voltage during use, without disconnecting, is not very useful. You don't know the complete circuit so you don't know what you're measuring. Disconnect the motor while it's powered and you can get a much more sensible measurement. If possible, do also measure the current the motors take - another important parameter for your circuit design.

2.5V is a very low voltage for even a toy motor. It's possible, but it's even less than the output of two AA batteries. The product info page doesn't give any info on what power it uses, how many batteries or so. The manual controller I suppose is doing on/off for two motors in two directions, and that's what you're trying to replace.

In general, relays are not the best option for switching low voltages. They make noise and are bulky. I'd be thinking of MOSFET switches. As added advantage, you may be able to regulate the speed of the motors by PWM, something a relay can't. To get the motors run in two directions you'd need an H-bridge type of circuit - four MOSFETS or relays per motor.

tablacsoki:
Using a motordriver:
When I measured the Volage of the wire (during use) it was 2,5V.
Can you suggest me a cheap way to control a motor like this?

How is the crane powered? If by batteries, what is the voltage of the batteries?

You also need to measure the current flowing into each motor before being able to select a driver.

For low voltage (<10.8v) the Pololu DRV8833 is a convenient driver with a capability to deliver 1.2 amps (or 2.4 amps if both drivers are connected to one motor).

…R

I think that you should think about positional awareness.

When a human being is using the controller, he holds down a button until the particular crane piece that button controls is in the desired position.

Trying to replicate that with a fixed time is likely to generate error. Worse, the error is cumulative if you are running similar sequences over and over.

Having sensors that report back position will let you run until the part reaches the desired position. Having encoders let you count the number of revolutions. Handy for the main cable.

Thank you for the advice, I agree... I try to solve one problem once :) But I will need to take care of this problem you wrote with other sensors, and my plan is to use the main cable. Thanks for confirming my thought without even asking =)