Swing door opener

Hi guys. I'm very nooby in arduino. I've bought a starter kit a few days before and played with it a little bit. Now I would like to create my first real life project. I want to develop a swing door opener system.

I need: 1) Servo which put the door knob down. 2) Servo for opening the door. This servo should open and close the door

I thought to do something like this, but a little bit smaller.

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But I don't really know what kind of servo should I use. Could anybody tell me what will be suitable for my case, please?

Regular size person door? Then you need something bigger than a RC hobby servo. I can't think of any that will be able to move a door.

Your photo shows that this kind of thing does exist as a commercial product. I can't see a homemade prototype getting any smaller than what you showed. Why not buy one of them?

i would agree as what you need is more like a linear actuator or gear driven high torque stepper motor and their driver boards likely a $100+

AND powerful door openers need suitable safeguards to prevent injury, and to allow emergency override which will make the project a a lot more complex.

...R

MorganS: Regular size person door? Then you need something bigger than a RC hobby servo. I can't think of any that will be able to move a door.

Your photo shows that this kind of thing does exist as a commercial product. I can't see a homemade prototype getting any smaller than what you showed. Why not buy one of them?

Yes, the regular size door. It's door to balcony. Do you think I need really powerful servo? Because the door pretty light and I thought the 15 kg/cm will be enough. Am I wrong?

MorganS: Regular size person door? Then you need something bigger than a RC hobby servo. I can't think of any that will be able to move a door.

Your photo shows that this kind of thing does exist as a commercial product. I can't see a homemade prototype getting any smaller than what you showed. Why not buy one of them?

Because I cant find any for reasonable price. The cost is more than 1000$. And the second reason is that I want to open the door knob from one remote control. And I think there is no product like this.

I cant use actuator, because I need to open the door manually sometimes.

I found the video, where the guy created the same project. https://www.youtube.com/watch?v=4f7VuxNcsfY

There is a link in the description below the video. But I didn't understand what kind of motor he uses. Because.

Robin2: AND powerful door openers need suitable safeguards to prevent injury, and to allow emergency override which will make the project a a lot more complex.

...R

I think for the first time I don't need any safeguards.

mqdb: I think for the first time I don't need any safeguards.

Keep those words convenient so you can read them again after someone is hurt.

...R

mqdb: Yes, the regular size door. It's door to balcony. Do you think I need really powerful servo? Because the door pretty light and I thought the 15 kg/cm will be enough. Am I wrong?

Try to measure the torque you use to open the door manually. I think you need a lot more than 15kg/cm.

mqdb: I cant use actuator, because I need to open the door manually sometimes.

And that makes the project significantly more complex.

MorganS: Try to measure the torque you use to open the door manually. I think you need a lot more than 15kg/cm. And that makes the project significantly more complex.

Could you tell me, please, how I can do it?

MorganS: Try to measure the torque you use to open the door manually. I think you need a lot more than 15kg/cm. And that makes the project significantly more complex.

I'm sorry for silly questions, but why more complex? Servo may be turned manually, mayn't it?

Guys, have you watched the video from youtube which I sent? For nooby like me it's kind of complicated, but I think it's not so complicated in general. There are just one motor. I think the most complicated part is to find out the type of the motor.

You know what kg-cm or foot-pound means? Were you awake in highschool physics? It's force times distance. 15kgcm is a force of 15kg at 1cm from the hinge. Or it's 1kg at 15cm from the hinge. (Not that kg is a unit of force but convention says that it's 9.8N.) Try to pick up a 1L container of milk with just one finger to feel how heavy 1kg is. Then apply that force 15cm from the hinge of your door.

I don't know about the servo you found but most actuators above that size can't be pushed manually.

Change the door “knob” to a lever and you will have many more options to activate it.

Lawsuits from injuries due to automatic door openers come from automatic closing. If you are only opening, then pretty safe.

Also, are the property owner? If not, then the owner will also be liable for what you do, even if they are unaware of your project.

Paul

MorganS: You know what kg-cm or foot-pound means? Were you awake in highschool physics? It's force times distance. 15kgcm is a force of 15kg at 1cm from the hinge. Or it's 1kg at 15cm from the hinge. (Not that kg is a unit of force but convention says that it's 9.8N.) Try to pick up a 1L container of milk with just one finger to feel how heavy 1kg is. Then apply that force 15cm from the hinge of your door.

I don't know about the servo you found but most actuators above that size can't be pushed manually.

If I'm not mistaken, open the door need less force than to lift 1 kg to 15 cm. Do you think Power HD 1201MG won't be enough to open the door?

Paul_KD7HB: Change the door "knob" to a lever and you will have many more options to activate it.

Lawsuits from injuries due to automatic door openers come from automatic closing. If you are only opening, then pretty safe.

Also, are the property owner? If not, then the owner will also be liable for what you do, even if they are unaware of your project.

Paul

Thank you for your response, Paul. Unfortunately I can't change the knob, because it's a balcony door and it has a specific structure. The door is in my house. So I think I shouldn't be afraid of lawsuits. However, there won't be so powerful motor and it won't be able to make any hurts.

This project is obviously above your current level of understanding, but it will be a great learning experience, so go for it!

I cant use actuator, because I need to open the door manually sometimes.

Perhaps a strong magnet could be used at the end of an actuator and a metal plate on the door. Scotty

mqdb:
I cant use actuator, because I need to open the door manually sometimes.

An electric clutch could po$$ibly work for you. When clutch is deenergized door opens as per normal. When clutch is energized door moves under influence of torque source.

YMMV

My go-fast boat uses one of these to open the engine hatch. Would probably work for your application. http://www.cpperformance.com/c-40-hatch-actuators-and-rams.aspx

If I'm not mistaken, open the door need less force than to lift 1 kg to 15 cm. Do you think Power HD 1201MG won't be enough to open the door?

You have misunderstood the concept of torque.

Yes, I think that servo is too small. But not by much. It might work.