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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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I thought I would post a copy of this here as well since people cant respond and talk about it in the ultimate guides section..
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For anyone interested in DIY speed controllers, here is one of the best guides to a useful robot wars capable speed controller I've seen on the net so far.
http://www.mcmanis.com/chuck/robotics/projects/servo.html
and the 2nd version with more details
http://www.mcmanis.com/chuck/robotics/projects/esc2/index.html
also, for those considering which fets to use, and wanting to know "which fet will do X amps ?", heres another page by the same guy that explaines quite well why "it isnt quite that simple"..
http://www.mcmanis.com/chuck/robotics/projects/esc2/FET-power.html
If the math scares you at first, perservere, read it all and try not to get confused by all the Rtheta(ja)'s until you have thought about his explanations a bit, its worth it..
If its really above your head, then ask yourself why you want to build your own speed controller.. if its because you want to save money, forget it, I guarrantee you wont, just buy one.. otherwise, strain that brain a bit and eventually it will all start to make sense, you need to know this stuff if you want to avoid making magic smoke.. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Fri Sep 10, 2004 2:50 pm |
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ffej
Experienced Roboteer
Joined: 22 Jun 2004
Posts: 595
Location: Kurrajong, NSW
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quote:
Originally posted by Spockie-Tech:
If its really above your head, then ask yourself why you want to build your own speed controller.. if its because you want to save money, forget it, I guarrantee you wont, just buy one..
Ill second you there. I spent forever bodging up my own controllers, and hacked oatley kits, just about every fight I lost with the original version of Singularity was due to controller failure (sliced bateries excluded ).
I eventually came to the conclusion that unless I were to put a fair amount of time(even more than I spent repairing the dodge controllers) and money into building a controller with a proper PCB with thicker than normal copper, I was going to have continual failures. After some consideration, I decided that I value my time much more than my money, and so went a bought an RS80. With so much added control, reliability and current limiting, ill never go dodge again. _________________ Jeff Ferrara
fb@ffej.net
ffej.net
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Fri Sep 10, 2004 10:13 pm |
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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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"I liked it so much, I bought the company !" ?
I understand what you mean though jeff, when you've been trying to achieve something, and you suddenly find a tool that allows you to work towards your goal much easier than you did before, its very easy to wax lyrical about its advantages to everyone..
I dont mean to discourage anyone from learning how speed controllers work, I did, and I enjoyed it greatly.. if anyone else wants to, I'll be more than happy to have someone to talk about such things with, and I might even learn something new myself from the discussion.
I like to make sure that it is being done because of "a desire to know" and a willingness to learn, rather than as a perceived cheaper short-cut to a goal of "just getting something that works". If thats someones goal - to get a working speed controller with as little effort as possible to allow them to reliably win with their bot, then I promise that buying one is the easiest route to that goal that involves the least expenditure of effort, time and money.
If however, the challenge of mastering the techniques required to make a little tiny chunk of silicon behave as a better conductor and switcher of massive amounts of electrical power than a huge piece of wire and mechanical contacts can excites you, and you dont mind the effort required to leap the many hurdles along the way, then its a very satisfying journey if you have the time and energy to make it yourself.
(actually, my initial motivation
was
to save money.. I knew that we needed to build quite a few bots ourselves to help kick-start the sport in Australia, and I hoped that by building our own, we would save money over buying 10 or more commercial units.. even so, I'm not sure it wouldnt have been cheaper to just buy them when you take into account the time I spent developing them (and that was with the help of the already existing OSMC design!), but I did enjoy learning about an area of electronics that turned out to be a lot more involved than I ever suspected before)..
So dont complain that its too complicated and isnt there a simpler way ?when someone who has done it points out the path they followed to get there for you.. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Sat Sep 11, 2004 2:48 pm |
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