Large Scale Central

I have a very good question I KNOW that TOC can answer for me!

Electronics Power and Sound
#1

I am trying to use TWO(2) switches to control my electric actuator removing the 2way momentary switch (DPDT) currently being used. The 2 switches I am using are simple momentary (SPST) that copletes the circuit or not (like most switches LOL).
2 wires comes from each SPST switch, 2 come from power and 2 come from the actuator itself. How do I wire (connect) the switches so one reverses polarity so one switch extends the actuator screw and the other retracts the actuator screw??? HELP!!!

This is all DC power 12volts.

I know I havent posted in awhile and this does not directly relate to trains as I am asking but it most certainly could be viable for the train world. This is what I want to do:

CATV sucks…I am trying to get a Lawn mowing company going to pay the bills (have I regressed or what!?) and I have a Craftsman Garden Tractor. I added an electric actuator (cool invention!) to get rid of the side handle. Works GREAT! But I am using a DPDT momentary switch to operate up and down. Now the throttle control for the hydrostat rearend is hand operated as is the steering. So when using the actuator for raisin/lowering my dozer blade I need 3 hands. Well the new thing in tractors is foot control freeing up your hands! Great but as of yet the old style cannot easily be upgraded thus my thinking outside the box!!!

I want to change the momentary DPDT switch to 2 SPST switches, one located on each footrest! The left would be up and the right would be down! BRILLIANT!!! This leaves the raising/lowering of the mower deck/dozer-snow blade with the feet while still being in total control!!! GENIUS!!!

TOC me friend…HELP!!! I KNOW it can be done but I can’t figure it out. So far I ‘think’ I need 2 power leads from there it gets pretty murky…

#2

Hi Mark -

One problem is that electrically 2 SPST do not equal 1 DPDT. You probably need 2 SPDT switches.

Do you have any way to diagram how the wires are connected to the current switch. Even a text representation using o’s for the terminals and —'s for the wires would help. Switches about as basic as electronic gets,so I’m sure there is a way to do what you want.

JR

#3

Mark,
You cannot do it with just two spst pushbuttons and DC. It would be possible with AC and steering diodes but you said DC.
As you require the switching to be somewhat automatic you can do it with two SPDT micro switches which are available in a pushbutton format.

I even have some heavy duty switches here I once used to aid disable persons who wanted to use RCS equipment. They may be available in the USA. They have a normally closed contact, a normally open contact and a common contact.
I have a circuit that would work. I also once used the circuit as a very crude direction control for electric motors using an R/C servo, the arm of which alternately moved two microswitches.

It is operated thus:
With both switches at rest no power goes to the actuator.
You would push button A to drive the actuator one way. When you let button A go there is no power to the actuator so it stays in that position.
To drive the actuator back to the original rest position you would press pushbutton B which reverses the polarity. When pushbutton B is released power is turned off leaving the actuator at rest back at the first position.

If the idea appeals I will try and dig up a pic of the circuit for you.

#4

“With both switches at rest no power goes to the actuator.
You would push button A to drive the actuator one way. When you let button A go there is no power to the actuator so it stays in that position.
To drive the actuator back to the original rest position you would press pushbutton B which reverses the polarity. When pushbutton B is released power is turned off leaving the actuator at rest back at the first position.”

THATS IT!!! THAT is EXACTLY what I want to do Tony!!!

#5

Here you go Mark. It is important where the wires go. It doesn’t matter what the polarity is. Just reverse the battery or actuator connections if they are wrong. I would suggest you suitably fuse it.

#6

I may be mistaken , but it looks like that circuit will give dynamic braking as well .
Looks good ,you must work in electronics ofr something .
Mike

#7

THANKYOU TONY!!!

Now the only thing is to find the switches with THREE ‘tabs’. Mine have only 2 to complete the circuit…Thanks SOOOOOO much again!

BTW…where is TOC? Not even a ‘howdy’ from him!?

#8

He’s lurking in the wings, awaitin’ all the answers, so’s he can jump in and change everythin’.
:slight_smile: :slight_smile:
j

#9

That’s why you ask for a SPDT switch. SP stands for “Single Pole” … a “Double Pole” switch is like two single pole switches right next to each other with the handles fused together. You only need one, as there are only two wires involved. Double Throw is necessary, since it has two contacts… one that is “Normally Open” meaning when at rest the contacts are NOT touching, and “Normally Closed” which means at rest, they are. When you move the switch against the spring, the position is “not normal” and the (normally) open contacts are closed, and the (normally) closed contacts are open.

When Radio Shack used to sell things that are not cell phones, you could get all manner of toggles and pushbuttons there… now you’ll have to find someplace that sells electronic parts… but the abbreviation SPDT for what you’re looking for is pretty universal… and if you ask for a SPDT momentary pushbutton, you’re pretty much going to get what you need from anyplace.

That said, isn’t there a version of the old floor mounted high beam switch that does this? One of those would hold up well to being stepped on, being designed for just that.

#10

Matthew, the old foot operated SPDT switch will not work.
They are a latch ON - Latch OFF type.
For that circuit to work safely Mark needs a pushbutton with momentary operation only.

#11

I have 2 SPST switches mounted in the foot rests already. But each switch only has 2 terminals.

#12

Mark.
Any regular microswitch has the correct SPDT method of operation.

What you need is one robust enough to handle being operated with feet.

An old DIP switch lighting control has the correct terminals but the wrong way of operating.

You could use two SPST pushbuttons but they would have to control two SPDT relays.

If that is preferred the change to the circuit is very simple.

#13

How simple and how much extra will it cost me???

#14

Mark.
Not much.
Use the existing spst push buttons to drive the coils of an automotive relay. One for up One for down.

Assume the connections on the relay are the same as for the microswitch. They should be marked on the relay.

I will be back in 10 days or so.

#15

What aboute the old style dimmer switches ( auto )

#16

Been busy.
Fighting with some yay-who’s in Boston.

#17
Curmudgeon said:
Been busy. Fighting with some yay-who's in Boston.
Some yay-who's huh? Damn yay-who's...I never did like those damn yay-who's...ESPECIALLY the Bastan yay-who's, they're the worst! LOL

Thanks for letting us know you are still alive brother!!!

#18

Damn Yankees! Do we need to launch a pre emtive stirike?

#19

I do a lot of work with folks on anti-spam, anti-spyware, anti-malware and such.
No expert, never claimed to be, just able to pass along what I have learned, what works, what doesn’t, what’s free, what’s a memory hog, etc.

I’ve recommended a site for a ong time called SiteAdvisor, you can run the link through and it will tell you if it’s safe from bad stuff that could happen to your computer.
Well, they got bought up by MacAfee in Bahstan.

The "Red X"ed one of my shipmate’s sites, local guy in our Sub Association.

Seemed they signed up and got 3.5 SPAM e-mails from all over, Russia, Romania, etc, and in print they blamed him for “selling” their e-mails.

He’s freaking furious.

So, I had signed up on the site, made a comment full of (expletive deleted)s (Just like that, too, probably 10 times), they certainly didn’t like it, found out you had no way to UNsubscribe, so we’ve been in a fight.
Got it solved tonight.

I would never recommend that place again.

#20

I had considerable problems with McAfee , and told them I would post their bad name as often as I could .
They had , against my express instructions ,nicked a year’s subs out of my credit card ,though I had told them 6 months previously that their service was crap , and left .
I had a devil of a job getting my money back , I got it in the finish , but they don’t give a shit who they upset , they got the money .
Do the people who work for them get moron training , or do they pocket any part of the subscription as a bonus ?
I would avoid them like the plague . I went to Norton --what a difference .
Mike M
ps so you are a Good Samaritan really at heart , Dave . Nice work .