Remote Door Opener/closer
I got tired of having to get up to open a door for my dog, so I built this in order to be able to open doors without moving.
Supplies
Materials:
RC car (or other source of motor)
metal strip (or other material for arm)
wood (or other base material if you chose to make a base)
A nut, bolt, and 2 washers (or other materials to allow arm to bend freely)
tape and/or zip ties (or other adhesives)
string (or other material to connect the arm to the door)
plumber's tape (or other material to hold motor in place)
Total cost is around $30, $20 for the RC car and about $5-$10 for the other parts.
Tools:
Drill (if you use any screws)
Saw (if you need to do any cutting)
Grinder (if you have any sharp bits that you want to smooth out)
Motor
You're going to need a motor powerful enough to open and close a door. I decided to use one from this toy car because it already has both a power source and a remote connected to it, so I wouldn't have to set that up myself. Your build is base off of what motor you chose, so it should be picked out first. Spoiler: it turns out that this motor isn't actually strong enough to open and close my door, so I recommend getting something beefier.
Arm
There's 5 parts to the arm:
- bar 1
- bar 2
- bar connector
- motor connector
- door connector
Its best to read through this whole section before you begin building since you will need to consider how all of your parts will work together.
What you use to make bars 1 and 2 doesn't matter as long as its strong enough to not break when pushing open the door and works with the other parts of the arm. I suggest using strips of thin but not flimsy wood or metal. I took a piece of scrap metal, cut it in half (don't want the arms to be too long, about 1 foot depending on how much you want your door to open) then grinded the sharp edges down (Pictures 1 & 2). I also rounded the end of bar 2 that connects to the door so that it doesn't damage the door.
Both bars will need to be connected in a way that allows easy bending of the arm. I suggest drilling a hole into one end of each bar, then use a nut, bolt, and washers to ensure that they stay connected and mobile. (Picture 3)
The motor connecter connects bar 1 to the motor. What you use to do this depends on your motor. My motor has a wheel on it so all I had to do was zip tie bar 1 to the motor. This part should be done before you attach your motor to the doorframe/wall and after your motor assembly (next step) is completed if you chose to attach your motor and battery to a base.
The door connector will connect bar 2 to your door. I've found that the best (and cheapest) way is to drill a hole in the end of bar 2 that is closest to the door, then tie a string to bar 2 and tape the other end of the string to the other side of your door (Picture 4). Its best to wait until your arm is attached to the motor and it's installed to your door frame to actually attach bar 2 to the door.
Motor Assembly
I used a scrap piece of wood as a base to connect all these parts, but if you want you can attach everything directly to your doorframe or wall.
Your motor should be placed so that it will spin perpendicular to the door hinges (as if it were driving across the door). With this in mind, the motor needs to be fastened tightly enough that it won't move. You want to use something stronger than tape or zip ties, so I used plumber's tape. After that you want to make sure that your battery is attached in such a way that it powers your motor without getting in the way of the arm. I put mine next to the motor, but you might have to put yours above it. I suggest using either zip ties like I did or screws so that the battery doesn't come lose.
You're Finished!
Now you're done! If you've done everything correctly you now have a remote-control door! Hopefully you picked a motor strong enough to open your desired door.