Electronics ~ Looking for motorized door schematic ~

I need help finding a schematic. What I would like to accomplish is basically a door that with a push of a button will open to a defined limit and on a second push to the same button close to a defined limit. Just like a cdrom drive tray. I do not want to use an old cdrom unless I can use just the electronics itself and not the mechanical parts. I am trying to minimize the space needed by the circuit.

I have searched and searched; stepper, servo, you name it. I have found many schematics but none that accomplish this seemingly simple task without the help of additional input, such as parallel port connections etc.

The closest is a project found HERE. His project includes some ics which are discontinued so I am unable to use his SCHEMATIC.

Any help is much appreciated and welcomed. I plan on using the circuit to control a Lilliput LCD touchscreen which I would like to motorize.

 

The easiest way is to put two momentary switches which will trigger when the door is fully open of closed (limit switches). As far as schematics go, you'll need an H-bridge to get bi-directional motor control which can be built with discrete components or puchased as a single chip.

For the rest of it, a microcontroller would make your life very easy. There's been lots of discussion of those here, google around for tutorials if you're interested.

If you were to go with logic circuits, I'm not certain how exactly you'd go about it, but it would probably involve a flip flop connected to your activation button so you get a different direction each time you push the button, then a latching circuit/SCR to keep it running until your limit is reached. If using an SCR for latching and a NC (normally closed) limit switch in series with it, then hitting the switch would interupt the current through the SCR and stop the motor.

 

Simple enough?

I made that circuit for a tray with only one switch that's activated at both ends. If you can get/make a tray with 2 switches, you can do it all with a couple of relays.

 

Seems simple enough. A couple of questions. With a press of the button the moror runs in forward, correct? What happens when the tray switch is closed? Does the motor stop, and if so does a second press on the button cause the motor to reverse? What causes the motor to stop in reverse? is it the same tray switch? I would love to use two limiting switches, is this possible with your schematic? I assume the motor is a 5v. And finally the transistors in the circuit are just general purpose npn's right?

Thanks for any input. I am always learning new things, and this is just one of them.

 

How about a look at Mashies site?
Maybe a servo with a "flat" potentiometer could be used?
As for the one-button input, i don't know...

 

Unfortunately I can't recommend you to use this circuit, as it has faults I haven't been able to fix

The motor is stopped at both ends by the same switch (I used a tray out of an old Acer 8x CDROM) and the button reverses the motor and activates it at the same time, to push the tray far enough for the switch to turn back on. (sorry if that's confusing, it's kind of hard to explain)

If you use two limiting switches, you won't need this circuit at all You should be able to do it with a few transistors or even some relays if you want to make it really simple. [edit: Although, now that I think about it, you would probably need a toggle circuit too.] I don't have PSpice installed , otherwise I'd make a new diagram for you. If I can find the file to reinstall it, I'll see what I can do...

 

Id be a lazy SOB and and hook up 2 limit switches to a PIC, a button for triggering it, and 4 mosfets for the motor.

Why think when you can have a pic do it for you.

Actually, now looking at the chart, on the microchip site, the PIC16F630 is only $1.89 at jameco, so that may be cheaper than using logic chips. If you have the programmer already that is. But you could make a JDM fairly cheap. if it would interest you to use PICs for other things, so the programmer wouldn't be a one time use thing.

Though with a pic you could make it so that when you press the button mid cycle it stops, and when you press it again, it resumes, if you need that ability.

 

Thanks for all your help. I think thet I will pursue the pic idea. I have had some interest in the area but no reason to follow up on it untill now. Thanks again everyone.

 

sorry, this might be a bit simple, but it works.. you need a polarisation changing switch, (a two pole changeover switch) two diodes and two limit-switches.. and the motor naturally..



The Kiss (Keep It Simple Stupid) motor control.

 

Thanks for the input but the circuit you provided uses a switch and not a button to activate the motor. What I am looking for is a single button to activate the motor. One press forward another press on the same button reverse.

 

Like this than;


Use a push-botton toggleswitch.. easy.. and the best og all, no programming needed

 

I think he was looking at making it so that you can quickly press the button, and the door will open to the limit and stop. press and release it again, it closes to the other limit and stops.

 

Therfore; push-botton toggleswitch, push it once, it closes, push it again, it opens...

BTW; why do people need a pic, for someting as simple as a one-function motor controller.. and use mosfets to drive them.. this circuit is mutch simpler, and therfore much more reliable.. nothing exept the eng

 

A pushbutton toggle switch would work in your example, but I am looking to use a small tactile button. I am basically looking for a cdrom drive tray control but without the cdrom. Thanks again.

 

I don't know why, people just like making things complicated. But with the PIC he might be able to add things such as a touch later if he feels like it. But as for reliability, I would expect mosfets to outlast relays, especially if heatsinked properly, and the PIC would last just as long. so the only possible things that could fail would be the things that are present in both circuits, the wire, the motor, and the switches.

Plus this is a good beginner project for pics, easy to code, no delys to mess with except a debounce delay. So it may be a learning experince for him also.

EDIT: do I smell a retractable bay bus?

 

Actually I am looking to have a 7" Lilliput touchscreen monitor INFO, which will be mounted in the face of a custom htpc case, pop out and slide down to reveal the DVD drive. I am looking to save space on the front of the case as well as the "I just think it looks cool" factor.