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Author Topic: Are ESC's really necessary for controlling motors?  (Read 981 times)

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Offline bsamuelsTopic starter

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Are ESC's really necessary for controlling motors?
« on: November 13, 2010, 06:05:58 PM »
Do ESC's provide anything else other than speed control? I need propulsion for a robot, tried converting servos to continuous rotation, found out that it's a bitch to figure out which resistance will keep it at neutral, so am not looking at motors as an option. However, ESC's appear to be quite expensive (50 bucks? loool) and on first look seem to be unnecessary. Is it possible to get a motor to "go" using an analog port on the axon?

Offline DUKELancelot

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Re: Are ESC's really necessary for controlling motors?
« Reply #1 on: November 13, 2010, 07:26:05 PM »
Quote
Do ESC's provide anything else other than speed control? I need propulsion for a robot, tried converting servos to continuous rotation, found out that it's a bitch to figure out which resistance will keep it at neutral, so am not looking at motors as an option. However, ESC's appear to be quite expensive (50 bucks? loool) and on first look seem to be unnecessary. Is it possible to get a motor to "go" using an analog port on the axon?

Uh, NO :(    (loool)

First off, do you even know what a Analog Port is. It's a input that RECEIVES a Voltage and is able to send the micro controller the number at a 8-32bit precision.

2. The Atmel ATmega640 can only withstand 20-30 mA per IO pin (A Standard DC motor pulls about 5000 mA at stall.) Thus placing a DC motor directly on a I.O pin would Fry/Kill your Axon instantly :P

3. A servo is nice because it has a built in ESC or Motor Driver, a gearbox, and a motor in a nice plug and play package. 

Quote
ESC's appear to be quite expensive (50 bucks? loool)
A good assembled ESC or Motor Driver should run at $40-$5000.


Quote
Is it possible to get a motor to "go" using an analog port on the axon?
[/quote] If you only want it to go only one way you could use a Power transistor.( not using a analog port of course.)

P.S This question has been ask before so I think a good hour of searching the forum for DC motors, and motor drives, and H-bridges would benefit you greatly.

As for a good quality Motor driver I recommend Pololu.com Motor drives.
Before you insult someone walk a mile in their shoes. Then your a mile away from them, and have their shoes.

Offline rbtying

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Re: Are ESC's really necessary for controlling motors?
« Reply #2 on: November 13, 2010, 09:41:42 PM »
As for resistance on a servo, for pretty much 100% of servos, you could just glue the pot at the servo's measured 90deg.  No need to figure out resistance.

Offline Soeren

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Re: Are ESC's really necessary for controlling motors?
« Reply #3 on: November 13, 2010, 09:57:30 PM »
Hi,

Do ESC's provide anything else other than speed control? I need propulsion for a robot, tried converting servos to continuous rotation, found out that it's a bitch to figure out which resistance will keep it at neutral, so am not looking at motors as an option.
You probably meant something else?


Is it possible to get a motor to "go" using an analog port on the axon?
No, but if you just want a motor to run, one direction, full speed, you can use a suitable transistor driven from a digital output. If you need speed control, same setup but use PWM on the output pin.

If you need speed control and direction, search the forum - I have posted a circuit to do both with a single transistor and a relay.
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

 


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