MX-3 Independent Rear Steer Setup article added.

[roktoy]

Originally Posted by grommit327

Question from a newbie and someone not to good with electrical stuff. Is it possible to wire this up for 3 position dig setup and use two momentary push buttons to achieve free wheel and locked rear with the servo? If there is what would the schematic look like for that setup? I am thinking that would be easier to use for dig than a toggle switch

There are three servo positions: left, center, right

Where do you want the servo with no buttons pushed?
Number 1 button pushed?
Number 2 button pushed?

Jay

[grommit327]

Originally Posted by roktoy

There are three servo positions: left, center, right

Where do you want the servo with no buttons pushed?
Number 1 button pushed?
Number 2 button pushed?

Jay

Well the way I picture it left would be both buttons open...or normal, centered would be button one closed and right would be button two closed(button one back open I would imagine). I just wasn't sure if it could be wired up that way since normal is usually centered.

Thanks for the help

[roktoy]

Ok, I think I know how to do it. Give me a day or so and I'll I'll post up a wiring diagram for your application.
Jay

[roktoy]

Ok, try this.

For this setup, we want the input node sitting at 5V (servo full left). Two push buttons are used.
Pressing Button 1 changes the node to ~2.5V and centers the servo. Pressing Button 2 grounds
the node and moves the servo full right.

You can change the added resistor value if you want a different mid-point voltage or change to
a potentiometer if you want an adjustable mid-point setting.

Jay

[grommit327]

Originally Posted by roktoy

Ok, try this.

For this setup, we want the input node sitting at 5V (servo full left). Two push buttons are used.
Pressing Button 1 changes the node to ~2.5V and centers the servo. Pressing Button 2 grounds
the node and moves the servo full right.

You can change the added resistor value if you want a different mid-point voltage or change to
a potentiometer if you want an adjustable mid-point setting.

Jay

Alright...I will dig into it this weekend

Let's see if I got this right. One node of each switch will be wired to the center node of where the factory switch was which goes to the IC. Button one's second node will also go back to the IC with a 10K resistor (or potentiometer) inline. Button two's second node will go to the black ground wire.

Does this sound about right? Sorry for the newb questions but thanks so much for doing the schematic for me

Joe

[yotachump]

This might be a little easier for you.

[roktoy]

Originally Posted by grommit327

Alright...I will dig into it this weekend

Let's see if I got this right. One node of each switch will be wired to the center node of where the factory switch was which goes to the IC. Button one's second node will also go back to the IC with a 10K resistor (or potentiometer) inline. Button two's second node will go to the black ground wire.

Does this sound about right? Sorry for the newb questions but thanks so much for doing the schematic for me

Joe

No problem. You have it right except Button one second node goes to 10k inline to GROUND....not back to IC.
Jay

[nathaninwa]

OK, I just did the 2 button momentary on switch mod. I dont have anyway to draw a picture so I will word it the best I can. I am using rear DIG and have the servo full left at normal (4X4), press button one and it gos center(free wheel), press button 2 and it gos full right(lock out). I had to wire it like this. From picture above, pull 2 wires from the far left black and wire to switchs............from one switch run wire to center circle, from other switch run wire with 10K resistor to center cirlce. nothing needs to be done with the green wire.

Tested and works.....just need to mount the switches and put back together. And from what I have been reading in the manual, you can set the EPA on the third channel.

Nathan

[roktoy]

Originally Posted by yotachump

This might be a little easier for you.

Looks like that setup defaults to ~2.5V. Pushing the left switch would get you ground
and pushing the right switch will get you 5V.....looks like a fine setup for rear steer
but doesn't look like what he wants for the dig.

Jay

[roktoy]

Originally Posted by nathaninwa

OK, I just did the 2 button momentary on switch mod. I dont have anyway to draw a picture so I will word it the best I can. I am using rear DIG and have the servo full left at normal (4X4), press button one and it gos center(free wheel), press button 2 and it gos full right(lock out). I had to wire it like this. From picture above, pull 2 wires from the far left black and wire to switchs............from one switch run wire to center circle, from other switch run wire with 10K resistor to center cirlce. nothing needs to be done with the green wire.

Tested and works.....just need to mount the switches and put back together. And from what I have been reading in the manual, you can set the EPA on the third channel.

Nathan

Sounds good. You just swapped the wires a bit to a slightly different configuration. Yes, EPAs built in.

Jay

[grommit327]

Alright....did it this weekend and it works good like I had hoped. The damn push buttons from Radioshack suck though. I need to find some better ones as these won't close the contacts consistently and the slightest jiggle with your finger allows them to open up.

Thanks for all the help with this
Joe

[TylerV]

Well, first off let me say that I don't have the most experience when it comes to wiring electrical circuits. I followed the guides and pictures here the best that I could and heres what I came up with.





Now the problem is that when I switch the switch into the down position, it turns my radio off. But it does move the servo. when I switch it to the up position, nothing happens, but the radio stays on. Neutral returns the servo to center and leaves the radio on. I hope you guys can help me!

[yotachump]

doesn't look like you removed the 3 channel switch from the circuit board.Maybe that could be the problem

[TylerV]

It may not look like it but I did remove the original two position switch from the board. The solder wick that I was using wasn't removing the solder from the posts so I used some snips to remove the switch from the other side. Do you think that it would matter if there's still little pieces soldered in there?

[TylerV]

Well I'm an idiot. Turns out having the right resistor actually makes a difference .

[torcez]

I have the MX3 2.4 and cannot remove the 10K ohm resistor because of the circuit board for the antenna. Can I do a STAGE 2 without removal of the 10K resistor or do a STAGE 1 and set my EPA off the center? Example - set one way to 100 and the other to 50 percent. Thanks in advance....

[roktoy]

Originally Posted by torcez

I have the MX3 2.4 and cannot remove the 10K ohm resistor because of the circuit board for the antenna. Can I do a STAGE 2 without removal of the 10K resistor or do a STAGE 1 and set my EPA off the center? Example - set one way to 100 and the other to 50 percent. Thanks in advance....

I *think* it will work if you use a 25k pot to GND in place of the 10k resistor and pot. Let me know.
Jay

[torcez]

Thanks for the quick answer. I did the STAGE 1 to see how it would work. I think that i can adjust my dig in the netural position and in the center (off) of the toggle and then set the EPA. Have not got the dig yet, I keep you posted on if it works or not. Thank you

[roktoy]

Originally Posted by torcez

Thanks for the quick answer. I did the STAGE 1 to see how it would work. I think that i can adjust my dig in the netural position and in the center (off) of the toggle and then set the EPA. Have not got the dig yet, I keep you posted on if it works or not. Thank you

If you're just doing dig and don't need even left/right throw, I think you could just do the stage 2 and leave the 10k resistor in.
Then just clock the servo arm to get the rough location and use the trim to fine tune.

Jay

[Mikey007]

did this mod to the mx3-s and it works but it seems like I'm getting rf interference from the switch to the antenna, and it is causing the servos to twitch. I can get it to stop, but when I put it back together it starts again.

Any ideas?