next year i am responsible for building my team a cool robot cart and ideas are at no shortage, but a major road block is that i am not sure where to find push button switches to make the pistons go up or down or turn lights on and off. what kind of switches should i use?
Are you using a robot controller to control these things, or is it hardwired?
If everything is 12v, then automotive switches (in either case) will work fine as long as the current doesn’t exceed the specifications. You can get these at RadioShack for a few bucks, or check your local electronics place.
(Our personal favorite was a switch RadioShack sold with a cover over the switch. After my experience in 2004 with autonomous, I’m glad it’s now hard to enable!)
not quite sure yet how i will do it but i will probably make a brain with old robot parts and control it like a robot with no wheels.
We experemented last year with a motorized cart but i fell through because we did not have time to program it or make a brain for it.
For the cart I built for the 2005 robot I used the electronics from our 2002 robot which we had to disassemble because we ran out of room in the shop 
. And we wired up the cart like the robot. For the lights bells and whistles we wired up a control panel full of 2 and 3 way switches. Everything we used went to a spike relay and to the fuse panel just like you would for a robot. It was safe and reliable and it worked for us so we went with that. The electronics board took less than a week to build and about 3 days to work out the bugs for the programming I know nothing about programing so we had our lead programmer do his thing it took him less than an hour to do.
hello!
I just thought I would share one of my favorite web sites for crazy buttons. They’re designed for computer mods, but many work for currents much higher than you’d see in a computer, and a few even are rated for AC, like the big old mushroom buttons that you just have to press once you see it, and the millitary-style flip-cover switches. Resellerratings.com seems to like them ok, so I’ll advocate them: http://directron.com/switches2.html Great selection, little pricey, but you get what you pay for, and switches see a lot of wear and tear.
Sparks
Dane,
Any mechanical, non lighted, switch rated for DC is, by default, rated for AC but the reverse is not true.
AC current passes through zero at some defined period (for example, every 120 Hz for 60Hz current). For DC current, the spark caused by a switch opening must be extinguished which is much harder to do.
Think of water flowing through a pipe… If you were able to instantaneously turn off a valve, the “water hammer” effect will blow the valve apart as the water has mass and you have attempted to stop it… F=ma or F=m*dv/dt so that F approaches infinity as dt approaches zero.
Likewise, any wire has inductance and V=L*di/dt such that the opening of any switch in a DC circuit instantaneously will cause the voltage to approach infinity and the switch will arc over.
The difficulty in switching DC was one of the factors in the great Nicola Tesla/Thomas Edison “war of the currents” debates in the 1880’s.
Edison lost…
Look back in these fori archives and you will find spirited debates among engineers when FIRST first introduced AC rated 60A circuit breakers to be used for a main battery disconnect (about 6 or 7 years ago).
Bottom line: Please do not use an AC rated product for DC unless you are sure…
Regards,
Mike
Mike,
You are quite right, and I thank you for pointing that out. Learn something new every day…
Thanks!
Sparks