How to keep a DC motor driven platform steady - Electronic Circuits Projects Diagrams Free

atferrari · 10th November 2005, 06:49 PM

I have kind of a small round board atop my bot, spinning driven by a DC motor. When the encoder shows that it has turned the exact required amount, I want to keep it steady unable to turn anymore until next order. External forces exist that could make it to rotate in one sense or the other.

Can this (breaking ?) be achieved with a common DC motor or should I resort to a modified RC servo? Whatever helps in saving power, much better.

No previous experience. That's why such a basic question. :?:

bloody-orc · 10th November 2005, 08:51 PM

use wormgear. it makes turning very slow, powerful and stiff. or put a brake on the motor (give v+ on poth leads of the motor)

atferrari · 11th November 2005, 12:58 AM

I prefer braking by shorting terminals. :idea:

**Nigel Goodwin** · 11th November 2005, 08:10 AM

Quote:

Originally Posted by atferrari

I prefer braking by shorting terminals. :idea:

That's what 'bloody-orc' said!, but I think the translation made it a little confusing?.

atferrari · 11th November 2005, 08:53 AM

In fact I was confirming that I understood what he said. :!:

Even I recall there is a chip (sure there are many!) that will do the shorting if the input signals are properly selected. An H bridge, perhaps?

**Nigel Goodwin** · 11th November 2005, 09:58 AM

Quote:

Originally Posted by atferrari

In fact I was confirming that I understood what he said. :!:

Even I recall there is a chip (sure there are many!) that will do the shorting if the input signals are properly selected. An H bridge, perhaps?

Yes, and not just a chip, a discrete H-bridge will do it as well (assuming it's designed to?) - in fact the specific way he worded his response was directly refering to an H-bridge system.

theinfamousbob · 11th November 2005, 01:15 PM

This might be a bit more than you need:

http://www.digikey.com/scripts/DkSea...361165&Site=US

I am going to be using one for a maze robot for competition and am tying it in to an OOPic.

It should do everything you need, and can take a bit of current.

Hope this helps!

atferrari · 11th November 2005, 06:46 PM

Hola Bob,
Your link is not working.

ops: Could you help?

Gracias.

theinfamousbob · 11th November 2005, 10:19 PM

Sorry!

The part can be found at:

http://rocky.digikey.com/scripts/Pro...14&M=LMD18200T

Hope that works!

-Infamous

atferrari · 12th November 2005, 09:33 AM

A good one. Gracias.

theinfamousbob · 16th November 2005, 01:23 AM

Glad to help.

addyismad · 23rd December 2005, 07:48 PM

use l293dne chip.....
gives kinda regenerative braking for a particular combo of inputs...

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10th November 2005, 06:49 PM	(permalink)
atferrari	How to keep a DC motor driven platform steady I have kind of a small round board atop my bot, spinning driven by a DC motor. When the encoder shows that it has turned the exact required amount, I want to keep it steady unable to turn anymore until next order. External forces exist that could make it to rotate in one sense or the other. Can this (breaking ?) be achieved with a common DC motor or should I resort to a modified RC servo? Whatever helps in saving power, much better. No previous experience. That's why such a basic question. :?: __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is.

10th November 2005, 08:51 PM	(permalink)
bloody-orc	use wormgear. it makes turning very slow, powerful and stiff. or put a brake on the motor (give v+ on poth leads of the motor) __________________ Need Help? Press F1 If that doesn\'t help you, ask me... I might know better.

11th November 2005, 12:58 AM	(permalink)
atferrari	Mechanical solutions to be avoided I prefer braking by shorting terminals. :idea: __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is.

11th November 2005, 08:53 AM	(permalink)
atferrari	Got it, Nigel! In fact I was confirming that I understood what he said. :!: Even I recall there is a chip (sure there are many!) that will do the shorting if the input signals are properly selected. An H bridge, perhaps? __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is.

11th November 2005, 01:15 PM	(permalink)
theinfamousbob	This might be a bit more than you need: http://www.digikey.com/scripts/DkSea...361165&Site=US I am going to be using one for a maze robot for competition and am tying it in to an OOPic. It should do everything you need, and can take a bit of current. Hope this helps! __________________ -Ian

11th November 2005, 06:46 PM	(permalink)
atferrari	Link doesn't work Hola Bob, Your link is not working. ops: Could you help? Gracias. __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is.

11th November 2005, 10:19 PM	(permalink)
theinfamousbob	Sorry! The part can be found at: http://rocky.digikey.com/scripts/Pro...14&M=LMD18200T Hope that works! -Infamous __________________ -Ian

12th November 2005, 09:33 AM	(permalink)
atferrari	Got it. Thanks A good one. Gracias. __________________ Agustín Tomás In theory, there is no difference between theory and practice. In practice, however, there is.

16th November 2005, 01:23 AM	(permalink)
theinfamousbob	Glad to help. __________________ -Ian

23rd December 2005, 07:48 PM	(permalink)
addyismad	use l293dne chip..... gives kinda regenerative braking for a particular combo of inputs... __________________ absence of evidence is not evidence of absence