Hi,

I would like to activate a motor with a mechanical tactical switch and sometimes also from an mcu in the same line, can you advice if you see any clash when both activated/connected to gnd at the same time?

Thank you in advance

 

To get any help you are going to have to explain the proline you are trying to solve. There is not enough information in your post to give any useful answers. Please describe what you are trying to do, and why, so people who want to help aren’t working in the dark.

 

its a simple motor activation with two basic options (led is the motor for the simulation), 1 by machanic switch and other by mcu, question is: in case when both sending gnd at the same time, will be any problem with that?

 

its a simple motor activation with two basic options (led is the motor for the simulation), 1 by machanic switch and other by mcu, question is: in case when both sending gnd at the same time, will be any problem with that?

That's not even close to answering my question, it's almost just repeating what you already said. How can you expect an answer when there is hardly any information provided?

When you are asking for free expert help with something, the least you can do is your part of it. I don't know why you would resist explaining what you expect this is going to do. You are presenting a "solution" and labeling it your problem. It's not. Your problem is whatever this is supposed to solve.

Maybe someone else will go through the tooth-pulling Q&A to help you. Good luck with whatever it is you are doing.

 

yes, thats the point to let others with experionce to answer.

 

if it wasnt clear by now, the led/motor turned on from a 5v and can get ground from 2 different sources: mechanical switch or from arduino that output gnd. question is, if acedetntly the switch is pressed and the mcu output gnd at the same thime, will that cause any issue?

 

No, the problem occurs when one is asserting ground and the other is asserting 5V. Then you have a short circuit. It might be that that is impossible with what you are doing, but we can’t know that because you won’t tell us what you are doing.

 

Hi,
Depending upon the resistor values, I don't see a short circuit condition?

@barg what are the resistor values?
E

 

which short circuit do you see? take a look again, 5v is only pull ups

 

Hi Eric,

R1, R5 10K
R3, R2, R4 1K

 

What is the required motor current? I'd be surprised if Arduino-Out can handle it; especially if R4 is 1k.
What is the purpose of R5?

 

Hi alec
R5 is a Pull up, pulled Low when Ard out=0
E

 

Hi barg,
When Ard_out = 0, LED On and Ard_In =0

When Sw1 closed, Ard_in=0 and lED On.

When Sw1 closed and Ard_out=0 then Ard_In =0

Looks OK to me.
E
Corrected typo error on R3 value.

 

What is the required motor current? I'd be surprised if Arduino-Out can handle it; especially if R4 is 1k.
What is the purpose of R5?

I’d d be surprised as well. A small motor likely will draw 1/2 amp or 500mA. The pins on an Arduino can only handle, safely, 20mA…

 

R5 is a Pull up, pulled Low when Ard out=0

R1+R2+R4 would seem sufficient pull-up without R5

 

Hi barg,
When Ard_out = 0, LED On and Ard_In =0

When Sw1 closed, Ard_in=0 and lED On.

When Sw1 closed and Ard_out=0 then Ard_In =0

Looks OK to me.
E
Corrected typo error on R3 value.
View attachment 301657

Thanks Eric,

i thought also when gnd meets gnd actually, there should not be any problem with that or any issue, but i wasnt sure..

All the best

 

This is a boolean logic problem. You need to define what happens to the light (or motor) in all four possible combinations.

SW1 SW2 LIGHT
OFF OFF
OFF ON
ON OFF
ON ON