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Joram
02-21-2008, 01:02 PM
Hi,
I still have an old pc here and I wanted to do something usefull with it. I want to make a pc-based robot with it but I don't know how to get the computer on a battery. Are there any examples on the internet?

DresnerRobotics
02-21-2008, 01:23 PM
Check out the picoPSU line if your PC has low enough power consumption. Otherwise they make bigger versions that are meant for Carputers. Logic Supply might sell those too.

http://www.mini-box.com/s.nl/it.A/id.417/.f

Joram
02-22-2008, 03:24 PM
ok, that will work
But how much Ah must a battery have to keep a computer and 2 motors running for an hour?

DresnerRobotics
02-22-2008, 03:39 PM
Depends completely upon how much power your computer and motors are pulling. Usually the easiest way to estimate runtime is by converting everything to watts. Voltage x Amps = Watts

Add up how many Watts your motors and computer are pulling, and compare that to the watt capacity of your battery. It's not perfect (batteries aren't perfectly linear in their drain), but it'll give you a rough estimate.

Matt
02-22-2008, 03:59 PM
Just as a point of reference, two of these batteries (http://www.trossenrobotics.com/store/p/3448-Gel-Cell-12V-7-2AH-Zeus.aspx) will run a mini PC and motors for more than a few hours. I've run a mini PC for up to 4 hours which was running windows on it.

Also, I'm assuming you are talking about bypassing the converter on the computer? You don't want to convert the battery up to 110 then plug the computer into it. That would be a huge waste of energy.

Logic Supply (http://www.logicsupply.com/categories/power_supplies) is a good place to research and buy power adapters.

Also, here is a power calculator (http://resources.mini-box.com/online/powersimulator/powersimulator.html).

cheers,

kdwyer
02-22-2008, 05:12 PM
(Jeez, I am lazy!)
As long as you will be near a PC, why not just offload almost all the processing to a desktop with a wireless connection? Then any time you want to run the bot, turn it on and turn on the PC and run the control program. And the program can be put on a thumb drive so it is really portable to any available PC.
It is a helluva lot easier than adapting a PC to be portable, and saves the battery power for the drive motors and sensors.

I told you I was lazy!

Matt
02-22-2008, 05:26 PM
That is a good point. You could always just use a serializer (http://www.trossenrobotics.com/store/p/5196-Robotics-Connection-Serializer-WL.aspx) for your bot and wirelessly control the bot from your old PC. The stinger (http://www.trossenrobotics.com/stinger-robot-kit.aspx) is a good choice too. Just tossing ideas out there. You might have your heart set on converting your old PC...

DresnerRobotics
02-22-2008, 05:46 PM
There is just something awesome about having the PC onboard however. Gives you greater mobility and a higher potential for onboard I/O. I dunno, I just enjoy having fully capable USB ports, sound, storage etc onboard.

Joram
02-23-2008, 02:11 AM
It is fun to make a robot from a computer, but thanks for the ideas

Alex
02-25-2008, 09:28 AM
It is fun to make a robot from a computer

I agree! Sure, offloading processing to another computer via TCP/IP, Bluetooth, etc. is ideal, but where's the fun in that? It actually adds a layer of complexity to your system. If you have the room and weight capacity to afford putting a full computer + batteries on your bot, why not do it? I know our PC bot that we made about a year and a half ago could run for quite a long time:


http://www.youtube.com/watch?v=rxZzhKMLipI