Introduction: Attic Elevator Using Garage Door Opener
The focus of this instructible is on the electronics. You may have a different used garage opener, it is only a matter of how you improvise on the mechanical design to retrofit the garage opener.
A number of reasons why I chose a garage door opener for my attic elevator:
1. It's easier to find a free used garage door opener such as Craigslist and Facebook Market Place.
2. The motor is powerful enough, a typical 1/2 HP motor capable of at least lifting 300 lbs (130 kg). It has a high gear ratio to allow heavier lifting. I haven't tried to test the maximum load yet. Besides, we should not put heavy stuff in the attic.
3. The motor is slow enough (high gear ratio) to allow better control.
4. It uses an inductive motor, which is brushless, very rudimentary in term of electronic control and durable. Typically the electronic fails first but you can still salvage the motor. In this instructible the electronics are discarded anyway.
Garage openers are designed with safety as the top priority, for obvious reason. The trade-off is it is designed to provide full power only at the initial motion. As a garage door begins to move, it relies on the counter torque of the garage door spring to eliminate the need for the motor to provide full power. That way the electronics provides safety sensing while it is in motion. That means after the initial motion, the safety features limit the power of the motor, which makes it less effective for an elevator. In this instructible I'll show how to fully utilize the power of the garage opener motor for an elevator which involves removing the safety electronics.
Step 1: Step 1: WARNING !!!
HIGH VOLTAGE: Motor control equipment and electronic controllers are connected to hazardous line voltages. When servicing drives and electronic controllers, there may be exposed components with housings or protrusions at or above line potential. Extreme care should be taken to protect against shock. Stand on an insulating pad and make it a habit to use only one hand when checking components, wearing insulating gloves are highly recommended. Always work with another person in case an emergency occurs. Disconnect power before checking controllers or performing maintenance. Be sure equipment is properly grounded. Wear safety glasses whenever working on electronic controllers or rotating machinery.
Even when the electronic is not connected, the capacitor(s) may still store high voltage.
And also remember this is a powerful motor. With the original electronics, it is rated for 1/2 HP, which is capable of lifting more than 300 Lbs (150 kg). Removing the safety electronics, it is more powerful than that.
Step 2: Step 2: Dissemble Garage Door Opener
Remove everything that is attached to the garage opener, including the casing.
If the garage opener was plugged in recently, do not touch any big capacitor(s). Any big capacitor may still store high voltage charge. You can use a screw driver to discharge it by shorting it.
Remove all of the electronics except:
1. Big capacitor.
3. Cut the transformer out of the PCB board, see the pictures. The transformer is used as a wire resistor and inductor, in my case the resistance is around 230 Ohm.
My garage opener has one big capacitor. If there are two big capacitors, the instruction will be a little bit different and I may post it in the future how to handle two capacitors.
Step 3: Step 3: Motor Description
The motor has four wires, it is an inductive motor, meaning it runs on AC current/voltage.
In my case, two wires are connected to the big capacitor (to run the motor).
1. Black ----> black (hot wire) from home power outlet
2. Red ---> An input of the 220 Ohm coiled resistor. The other end of the coiled resistor is connected to the home power outlet white wire (neutral wire).
3. Orange ---> already connected to the capacitor. This line will be used for switching in later step.
4. Yellow --> already connected to the capacitor. This line will be used for switching in later step.
The schematic describes how the motor works. The switch from White to either Yellow (Y) or Orange (O) to turn the motor one direction or another. The 230 Ohm resistor and inductor is used to smooth out the motion, it starts and stops.
Step 4: Step 4: Build a Switch Box
For safety, it is important to build a well insulated switch box to prevent electrocution.
Two momentary push buttons are used (example pictures and schematic) to switch the motor, one to rotate the motor one direction, and another button to go the opposite direction. See the picture the parts I ordered as an example.
Here is the link to my Thingiverse to 3D print the casing: https://www.thingiverse.com/thing:4620531
Step 5: Step 5: Full Schematic
See the full schematic of the wiring.
When "S1" switch is pressed, the motor goes one direction and vice versa with "S2" switch is pressed.
Step 6: Step 6: the Mechanical Part of the Elevator
This instructible is focus on the electronic part. The mechanical part can be freely improvised according to the dimension and weight of materials to be lifted.
In my case, the parts for the rollers can be 3D printed from my Thingiverse. The pictures should suffice to give an idea how to design a railing system to roll up and down the elevator.
Step 7: Ladder
I use a rope ladder to climb up and down, it is easier to pull it up. For efficiency it is recommended to have two people, one on the ground and another person in the attic.