2 replies to this topic

[Eddie Fleming]

I like simple things that work. 

 

I use Difalco controllers. I like Ruddock controllers. I think many controllers are to expensive for the good of our hobby.

 

There is a current thread about brakes on Difalco controllers and possible ways to improve them. Rather than moving that thread off topic I am starting this one. 

 

With the simple controllers above the wiper moves across the contact board and goes to a off position before the brake contacts close. With something like the Third Eye the wiper is still in contact with the power bands when the brake contact is closed. obviously the brake contact must switch off the power bands and engage the brakes without carrying the breaking current through the brake contacts, The brake pot on the THird Eye does not appear to be a current-carrying pot but rather a control for the FET brake.

 

My question is could this FET brake system be retrofitted to a simple controller in place of the current contact and resistor pot braking?

[rmjlmartin]

The short answer is yes, it can be done. In fact, the older Third Eye Renegade had FET brakes, but a BJT (TIP35 in a Darlington arrangement) throttle. I also have a friend who has successfully experimented with using transistor brakes on controllers he's built.

 

The long answer is that it's much more complicated. I have an old Third Eye Renegade that I want to trace at some point, to see if I can understand the circuit, but it's a real serpent's nest inside that transistor unit box. (see the pictures in this post- http://slotblog.net/...-controller-id/) The transistor would have to be triggered differently than the Third Eye, but it is possible.

 

Personally, I prefer the simplicity of a Difalco or Ruddock, but if someone can come up with a way to do transistor brakes that's not so complex, I'd be game to give it a try.

[Bill Seitz]

Eddie, I think I'm the friend Jason is referring to. I'm retired from an education and engineering career in electronics and play with electronic ideas in my slot car hobby building my own controllers. Like you, I prefer keeping things simple. Jason has given me the opportunity to explore the internals of the Hitman and Renegade controllers he owns, since aside from some Difalco conversions early on, I've designed and built the controllers I use today using Parma Turbo handle internals. Third Eye's FET design is more complicated than a Difalco or Ruddock with an entire additional layer of electronic devices in the the throttle. I haven't examined closely how the brake circuit is facilitated. I attempted a simpler FET throttle circuit than the one Third Eye uses and was unsuccessful with it. It needs some more development work that I've not had time for due to other higher priorities. I've been experimenting for several years using transistors in the braking circuit. Simple circuits work great as switches, but my experiments with a simple variable electronic brake have been less than thrilling. For the most part, a well designed resistor brake works as well and is far simpler. There's still no magic that turns off the throttle and turns on the brake. The black track lead is part of both the power and brake circuit, so must be switched between the two or the power must be turned off before the brake circuit to prevent a short from throttle to brake ground. I expect Third Eye is doing this by an alternate method to what we are familiar with in Difalco, Ruddock, and others that use a Parma/Russkit-style trigger/wiper throttle system with isolated bands or critically spaced contacts. In my first controller builds, I used two relays, the familiar SPST full-throttle switch, and a SPDT (double-throw) switch in the black lead that physically disconnected black from the power circuit and connected it to the brake circuit. Since then I've eliminated the second relay by making sure the the two circuits are switched appropriately by the mechanical design of the Parma Turbo handle which I use on all my controllers.

 

My controller experiments are on-going. I'm in the middle of another round of changes after my latest testing in preparation for another on-track test session in about a month. That won't be the end; more will take place after the next session. For everything I try, even stuff that doesn't work so well, I get new ideas or modifications that I then want to try. I'll probably be doing this until I get too old to solder anymore. If you're interested in a further chat on my electronic controller experiments, simply PM me. Just don't expect to learn how to add a half-dozen knobs and switches that may not be necessary anyway, digital computers in a controller, and contactless sensors. I don't find that necessary and don't go there.