Author Topic: Choosing the right diode for the situation  (Read 1049 times)

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Offline vipulan12Topic starter

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Choosing the right diode for the situation
« on: August 19, 2012, 01:39:35 PM »
Hey guys I have this motor I want to use for my arduino but I don't want to destroy my arduino because of the reverse voltage the motor will produce

so how do I choose the right diode for the situation and  How exactly would I calculate this?

just in case your wonder where i got this motor from
 -I got the motor from the rc car that tonka made but its fairly old
 -I tried to see if i could reuse any diodes in the circuit but I couldn't find any anywhere
 -the car runs on 4 double AA batteries

Offline Soeren

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Re: Choosing the right diode for the situation
« Reply #1 on: August 19, 2012, 03:53:31 PM »
Hi,

Hey guys I have this motor I want to use for my arduino but I don't want to destroy my arduino because of the reverse voltage the motor will produce
You're not trying to conect a motor directly to an I/O pin on the Arduino I hope?


so how do I choose the right diode for the situation and  How exactly would I calculate this?
Diodes are not calculated, but chosen for the pararmeters you have.


-I got the motor from the rc car that tonka made but its fairly old
 -I tried to see if i could reuse any diodes in the circuit but I couldn't find any anywhere
 -the car runs on 4 double AA batteries
We could try to calculate how fast you'd ruin your Arduino if you connect it directly, but it'd probably be less than 1ms, so do we bother  ;)

You need a motor driver in-between and that is what you protect with diodes.
To find out what power handling is needed from the driver, you need to measure your motor.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline vipulan12Topic starter

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Re: Choosing the right diode for the situation
« Reply #2 on: August 19, 2012, 05:17:37 PM »
but why not,

what's wrong with connecting the motor directly to the arduino (with diodes)? 

and what does the motor controller do exactly(how does it generally works?

Offline vipulan12Topic starter

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Re: Choosing the right diode for the situation
« Reply #3 on: August 19, 2012, 05:19:10 PM »
sorry not motor controller but motor driver(is there a difference?)

Offline Soeren

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Re: Choosing the right diode for the situation
« Reply #4 on: August 19, 2012, 07:27:05 PM »
Hi,

but why not,

what's wrong with connecting the motor directly to the arduino (with diodes)? 
You destroy the microcontroller in the Arduino, either fully or "just" one (or more) I/O pins.


and what does the motor controller do exactly(how does it generally works?
It takes a low current in and gives a higher current out.


sorry not motor controller but motor driver(is there a difference?)
A motor driver is just a current amplifier, while a motor controller implies that there's some kind of logic circuitry (perhaps a microcontroller) involved, but sometimes they get mixed up.


Please use "Modify" rather than serial posting!

And please start reading some basic electronics tutorials (Google is your friend) - you'd be able to answer most of your questions here yourself with just a little bit of reading.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline jkerns

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Re: Choosing the right diode for the situation
« Reply #5 on: August 20, 2012, 07:10:19 AM »
Read the specifications on your Arduino - pay particularly close attention to how much current the I/O pins can handle. Compare that to how much current you motor will be using. You can't put 0.5  pounds in a bag that only holds 0.02 pounds.
I get paid to play with robots - can't beat that with a stick.

http://www.ltu.edu/engineering/mechanical/bachelor-science-robotics-engineering.asp

 


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