Re: Reducing voltage
"Matthew J. Chiles" <[email protected]> Mon, 23 Nov 2009 17:13:35 GMT
| Newsgroups | gmane.comp.hardware.lego.robotics |
|---|---|
| Organization | None |
| Message-ID | <[email protected]> |
In lugnet.trains, David Laswell wrote: > Our club lets kids run the controller for one of the lines when we do certain > events (like, right now, with Detroit Festival of Trees), but we could use a way > to forcibly limit the speed on the line that they're allowed to run. One way > that's really easy is to just build physical stops onto the top of the regulator > so the dial won't turn as far in either direction, but that makes it difficult > to actually operate the dial and won't be much fun for the kids. The other > solution I just came up with would be to maybe limit the voltage going into the > regulator. And that's where there's a problem. LEGO power adapters, for some > odd reason, output in ~9vAC, not DC. Finding an AC-AC power adapter is > difficult at best, and the only two that I can find through Radio Shack (the one > place I knew of that _does_ sell them) run 9-13vAC or 18-24vAC, which is not > going to help at all. They do sell an adapter that goes as low as 3v, but it > outputs in DC instead of AC, and I'm not having much luck doing a generic > internet search for adapters that output in AC below 9v. Does anyone know where > I might be able to find such a beast? Years ago PNLTC used to do this for the kids table at the show. From what I recall, we just drove a screw though the controller at about the 4th notch in the black area on each side to keep it from turning too far. It is a very long lasting, inexpensive and easy solution. Any old PNLTC guys out there remember exactly how this was done? If no one pipes up, I would unscrew a controller and see where the screw would stop the dial without damaging any internal components -Matt :)