Hello everyone and thank you for all of the great ideas and suggestions you have provided me and many thanks to “sghioto” for the great circuit designs. How ever I have apparently upset some of you and ruffled your feathers and I am deeply sorry ;<(.

So for all of you who need to know all of the details, here goes.i
I am into 3D printing and have a couple of Bambu printers and one of them is the A1 printer with a AMS lite which is a multicolor automatic filament system. This system will automatically switch color of filament in that part of the print. Each color change requires the filament that is being used is pulled back and then the next color is feed into the extruder. This is how a AMS system works. As part of the changing from one roll to another the system requires the filament to be pulled back from the extruder and in doing so the AMS lite does not have a rewind feature instead it uses the stored mechanical energy and when the filament needs to be pulled back a spring int the spool will make the filament rewind as the feeder motor pull back the filament about 70mm. It’s a nice system when it works properly but they are prone to stick and not keep the slack out allowing the filament to get tangled and stop the print. Also the AMS lite does not have a dry box to house the rolls of filament. The filament is very prone to moisture and needs a dry box, that is what I am making and want to get away from the mechanical retract. Hence the circuit I’m needing and with this circuit I’ve made it using relays and work quite well, but bulky and too big.

This is how I want it to work, when it time to change roll colors the AMS pull the filament back with the feed motor and this feeb motor runs on 2 to 2.2 volts to pull it back and this action takes about 3 to 5 seconds and this is the 2volt trigger for my circuit. When the two volt is present it will turn my retract motor it also activates a simple timer . When the 2volt goes away the timer shoots a 12 volt pulse for about 1/2 second.

The reason for this very short reverse is to disengage the drive gear from the motor to the spool roller. This gear disengagement is a drive gear mounted to a swinging arm that drives a satellite gear and the drive gear has a little drag making the satellite gear rotate to engage the spindle gear. Once this gear is in the drive position when everything is stopped the gear stays engaged locking the spindle which will not allow the spindle to turn the other way and that is why I need the very short reverse, to pull the gear back out of the way.

I hope this gives you the information you needed and again so sorry I did not say all of this In the beginning and did not intend to make this a game.

Thank you, Ron

 

One version:
With pulses not active the motor is OFF.
2V pulse turns ON Q5,Q3,Q6 and Q2. Motor runs from B to A.
12V pulse turns ON Q7,Q4, and Q1. Motor runs from A to B.
View attachment 368997

Sghioto, may I ask you a question on the use of Q6 and Q7. Are these to protect the circuit when switching from forward to reverse?

Thank you, Ron

 

Sghioto, may I ask you a question on the use of Q6 and Q7. Are these to protect the circuit when switching from forward to reverse?

Thank you, Ron

No, they are only needed to switch the correct pair of mosfets (Q1/Q4) when the 12V pulse is activated.
As long as the 12V pulse arrives after the 2V pulse goes back to zero no other protection is needed.

 

No, they are only needed to switch the correct pair of mosfets (Q1/Q4) when the 12V pulse is activated.
As long as the 12V pulse arrives after the 2V pulse goes back to zero no other protection is needed.

Thank you, I added my simple timer circuit to your fantastic circuit. It is a 12vdc 1050 ohm coil reed switch the reed switch is a small spdt reed switch. The switch allows the the forward circuit to charge a capacitor and bleed resistor and this 12volt charged capacitor and when the current stops on the forward position it turns off the SPDT reed And dumps the 12volts to trigger the reverse side circuit. What do you think, will this work well or is there a better way to do that. I know I will have to play with the capacitor and bleed resistor to get my reverse pulse to last 1/4 to 1/2 seconds.

Thank you, Ron8

 

Thank you, I added my simple timer circuit to your fantastic circuit.

Can you show that in a schematic?

 

Hi sghioto, sorry for the confession and want to thank you for your help and ideas.

Ok, let me clear things up. I need a nice smaller circuit using mosfets to switch to control a 12vdc motor @20ma forward and backwards. One direction is controlled by a 2vdc source and the other direction with a 12vdc p for 1/2 second and and quite. The motor is off until the next 2volt signal for approximately 3 to 5 seconds. The power goes away it starts the timer 12vdc pulse to the other direction for 1/2 second.

I like the circuit with the mosfets you showed, it need to be controlled with the 2volt for one direction and 12 volts for the other direction.

If anyone is interested on what this is used for, it is a way to use the (3D printing) Bambu AMS-lite so I can use my own feeder boxes and replace the problematic mechanical retract system. I can supply more details if anyone wants to know more about this project?

Thank you, Ron

This is a typical X-Y problem, meaning that you are attempting to solve a problem (Y) without fully stating the real problem (X). Just so that you know and can avoid a lot of misunderstandings next time. This is what you should have said in your opening post. This is not just a problem of reversing a motor direction. This is more than that. This is a timing control problem. The proper way to communicate the problem to others is to draw a timing diagram that shows signals, events, voltages on the y-axis and time on the x-axis.

Here is an example of a timing diagram. (It lacks the time scale units on the x-axis and voltage scale on the y-axis.)

 

Can you show that in a schematic?

I’m sorry, I thought I did attach it. I’m am sending it again

 

This is a typical X-Y problem, meaning that you are attempting to solve a problem (Y) without fully stating the real problem (X). Just so that you know and can avoid a lot of misunderstandings next time. This is what you should have said in your opening post. This is not just a problem of reversing a motor direction. This is more than that. This is a timing control problem. The proper way to communicate the problem to others is to draw a timing diagram that shows signals, events, voltages on the y-axis and time on the x-axis.

Here is an example of a timing diagram. (It lacks the time scale units on the x-axis and voltage scale on the y-axis.)

View attachment 369050

As I stated in my reply #41 I tried describing in better detail and sorry if these details were not enough for you I’m sorry again. I did not come here to ruffle feathers just looking for advice and help. I am very new to this as I stated in my very first post and a newbie. This was an idea I have and making it as I go along so I really did not know how to call this out and mostly wondering if it could be done….

Again I’m not hear to make the big fish in this pond upset, please have a little forgiveness for my stupidly.

 

As I stated in my reply #41 I tried describing in better detail and sorry if these details were not enough for you I’m sorry again. I did not come here to ruffle feathers just looking for advice and help. I am very new to this as I stated in my very first post and a newbie. This was an idea I have and making it as I go along so I really did not know how to call this out and mostly wondering if it could be done….

Again I’m not hear to make the big fish in this pond upset, please have a little forgiveness for my stupidly.

You did not ruffle feathers. I am just pointing out that there was a more efficient way to start this conversation.

50 posts later and you still have not arrived at a solution.
The reason?
Poor communication in the first place.

By the way, there is no way I am going to wade through your post #41, when all of that could be communicated in a simple timing diagram.

A picture is worth a thousand words.

 

You did not ruffle feathers. I am just pointing out that there was a more efficient way to start this conversation.

50 posts later and you still have not arrived at a solution.
The reason?
Poor communication in the first place.

By the way, there is no way I am going to wade through your post #41, when all of that could be communicated in a simple timing diagram.

A picture is worth a thousand words.

DIDN’T KNOW HOW TO DO THAT!!!!!!!!!

 

DIDN’T KNOW HOW TO DO THAT!!!!!!!!!

This is a good time and place to learn how to do that.
No reason to shout.

 

What do you think, will this work well or is there a better way to do that.

Verified operation using a SPDT reed relay, RL1.
When first powered up C1 will charged through the NC contact of RL1 and drive the motor in reverse for appx .5 seconds.
The 2V trigger pulse will activate RL1 and discharge C1 through R3.
When RL1 drops out C1 will again charge through the NC contacts and reverse the motor.