Help designing switching circuit...
Help designing switching circuit...
(OP)
This is kind of hard to explain...especially at 2:00 AM. :) The transmission in my truck is completely electronically controlled. It's an automatic, but I'm turning it into a part time manual.
What I want to have is a control somewhat like in race cars - two momentary buttons, one for up shifting and one for down shifting.
My trans is controlled like this:
SOL1 SOL2
1st On Off
2nd On On
3rd Off On
OD Off Off
Does anybody have any thoughts about where to start designing a circuit that would allow me to switch those solenoids on and off, using only two momentary buttons?
Thanks!
What I want to have is a control somewhat like in race cars - two momentary buttons, one for up shifting and one for down shifting.
My trans is controlled like this:
SOL1 SOL2
1st On Off
2nd On On
3rd Off On
OD Off Off
Does anybody have any thoughts about where to start designing a circuit that would allow me to switch those solenoids on and off, using only two momentary buttons?
Thanks!





RE: Help designing switching circuit...
RE: Help designing switching circuit...
RE: Help designing switching circuit...
You need an up/down binary counter (two stages) and also debouncing for your switches. Arrange the switches so that the counter counts up one when the up switch is actuated and down one when the down switch is pressed. You have to make sure that the counter does not wrap around from state three to state zero and vice versa. Do that by decoding the zero state and block the down switch and also decoding the three state and block the up switch (the decoders will act like limit switches - in a way). These two decoders will also be used for two of your solenoids.
Two more decoders are needed for state one and two and control the other two solenoids. There shall be drivers or transistors if your solenoids need some current - and I am sure they do.
You could also talk to someone that can do it in a small micro for you. It should not take many hours to get it up and running.
RE: Help designing switching circuit...
Dave
RE: Help designing switching circuit...
I forgot to mention that you need a reliable power on reset (POR) circuit that puts the counter into neutral state when turning on. Hmm... I think that you will need a five state counter then. So you will need three binary stages (counts 0 1 2 ... 6 7) and decode state 1, 2, 3, 4 for the solenoids. State 0 is the idle state and also the power-on state.
I think that a micro will be the better choice after all.
RE: Help designing switching circuit...
http://www.baumannengineering.com/elect.htm
RE: Help designing switching circuit...