Author Topic: Voltage Regulator Newb  (Read 2639 times)

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Offline Half ShellTopic starter

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Voltage Regulator Newb
« on: November 05, 2007, 10:48:04 PM »
So I am working on one project that the motors run at about 5 volts and another where I'll be dealing with 9 volts- since my micro controller runs at 5 volts and I want to make the robots as secure as possible, should I use voltage regulators? If so, how would I use them and what kind would I need?

I appreciate any help given to me.

Offline SomeSaba

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Re: Voltage Regulator Newb
« Reply #1 on: November 05, 2007, 10:59:27 PM »
Hello  ;)

I think this article will help you:

http://www.societyofrobots.com/schematics_powerregulation.shtml

if u dont wanan read it, scroll down to the bottom there's a schematic.


Offline Half ShellTopic starter

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Re: Voltage Regulator Newb
« Reply #2 on: November 05, 2007, 11:00:15 PM »
Wow... I feel silly.

I scanned the site and couldn't find a tutorial on it. Now I feel kinda silly.

Thanks!

Offline Half ShellTopic starter

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Re: Voltage Regulator Newb
« Reply #3 on: November 05, 2007, 11:06:50 PM »
I read through the tutorial and see the diagram - how do I decide what fuse to use?

Also, am I right in saying that I basically need to buy a switching regulator and voltage regulator for every robotics project I do?

Offline frank26080115

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Re: Voltage Regulator Newb
« Reply #4 on: November 06, 2007, 12:54:53 AM »
When a fuse is used between the regulator and battery, they protect your battery from short circuiting (lithium batteries can explode), if you are not worried about wasting a battery when you short it for too long, forget about the fuse. You hardly see anybody using one on a small robot using 9V batteries.

If this is for a non-mobile power supply, I'd use a fuse that is rated higher than what I calculate my circuit will need at most.
If I have two motors, I'd estimate about... 4 amps max maybe?

Offline bens

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Re: Voltage Regulator Newb
« Reply #5 on: November 06, 2007, 02:18:12 AM »
Also, am I right in saying that I basically need to buy a switching regulator and voltage regulator for every robotics project I do?
You only need a switching regulator if your battery voltage is not at the level you want for your motors or servos (or if your battery voltage is less than 5V).  In a typical robotics application you'll probably just want a 5V linear regulator to power your logic; your motors can often just be powered straight off your batteries.

Offline Admin

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Re: Voltage Regulator Newb
« Reply #6 on: November 06, 2007, 09:13:32 AM »

Offline Steve Joblin

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Re: Voltage Regulator Newb
« Reply #7 on: November 06, 2007, 10:38:48 AM »
For most small robots, the "standard" 5 volt Regulator of choice is the LM7805... the LM2940 is also a popular one as it is "low voltage drop out".  Remember to use filter caps on both the input and output sides along with a heat sink!

Offline JonHylands

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Re: Voltage Regulator Newb
« Reply #8 on: November 06, 2007, 12:27:12 PM »
I typically use an LM2940 for size-limited voltage regulators, or where I don't need high efficiency.

Building a switching regulator from scratch is annoying - there are a bunch of hard-to-find parts to deal with, as well as the fact that in order to be a reasonable size, you need to work with surface mount. Lately, I've started using the Dimension Engineering 5 volt switching regulator, and I have to say I really like it:

http://www.dimensionengineering.com/DE-SW050.htm

For $15, its hard to beat, and it will handle 1 amp of output. They also have a 3.3 volt version if you need that voltage. They have another regulator that is really nice - the AnyVolt Micro.

http://www.dimensionengineering.com/AnyVoltMicro.htm

It allows you to feed in almost any voltage (2.6 - 14 volts), and get out any voltage (2.6 - 14 volts). I use this regulator in BrainBot to step up the 9.6 volt battery power to 12 volts for the camera.

- Jon

Offline Half ShellTopic starter

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Re: Voltage Regulator Newb
« Reply #9 on: November 06, 2007, 01:54:17 PM »
Alright, I bought a couple of 1 amp 5 volt regulators and a variable regulator from radioshack, surprisingly not for that much. They should hold me over until I build a much larger more powerful robot.

Plus, with all that I've read and from your kind advice I think I have a handle on how I will be using the regulator.

Out of curiosity, does anyone have a free schematic making program I could use to draw out my robot diagrams ahead of time?

Offline Admin

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Re: Voltage Regulator Newb
« Reply #10 on: November 06, 2007, 01:57:44 PM »
Quote
does anyone have a free schematic making program I could use to draw out my robot diagrams ahead of time?

http://www.societyofrobots.com/electronics_Eagle3D_tutorial.shtml

You keep forgetting to search first :P

 


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