I live in residence at the University of Toronto, and in my building we have to use key cards to enter and exit our rooms. Like many students around me, I often forget my key card inside my room when I leave, locking me outside!
EDIT: there is a youtube demonstration at http://www.youtube.com/watch?v=2v30EHG4x_s
So, I decided to design a solution- an electronic door-opener which pulls down the door-handle of my door, allowing me to enter without my key.
If you have a similar situation, you might want to do something like this, but this was more of a fun weekend hack than a real attempt at an implementation, hence the huge quantities of duct tape.
EDIT: there is a youtube demonstration at http://www.youtube.com/watch?v=2v30EHG4x_s
So, I decided to design a solution- an electronic door-opener which pulls down the door-handle of my door, allowing me to enter without my key.
If you have a similar situation, you might want to do something like this, but this was more of a fun weekend hack than a real attempt at an implementation, hence the huge quantities of duct tape.
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Signing UpStep 1: Parts list
For this project, which was completed over the course of a weekend, I used some spare parts and some new ones, making the overall cost very low.
Power Supply/Regulation
- A 5V regulator (I used L7805)
- 100uF and 50uF capacitors (I used random ones lying around, use whatever you have)
- A 12V 1A wall-wart power supply (don't use less than a 1A supply, the motor needs a lot of current!)
Microcontroller
I used a PIC16F506, any reasonable microcontroller will work.
Keypad setup
- 8 resistors (used for pull-down, I used 10K, anything around that area or less should work great)
- 16-key keypad (any normal matrix-style keypad will work)
Motor setup
- A $4 12VDC motor with a gear on the end
- A 5V relay
Miscellaneous
- A PC speaker (any speaker capable of beeping is fine)
- A prototyping board of some kind, or breadboard
- Duct tape (you know it!)
- Soldering iron, solder, flux, and the like
Power Supply/Regulation
- A 5V regulator (I used L7805)
- 100uF and 50uF capacitors (I used random ones lying around, use whatever you have)
- A 12V 1A wall-wart power supply (don't use less than a 1A supply, the motor needs a lot of current!)
Microcontroller
I used a PIC16F506, any reasonable microcontroller will work.
Keypad setup
- 8 resistors (used for pull-down, I used 10K, anything around that area or less should work great)
- 16-key keypad (any normal matrix-style keypad will work)
Motor setup
- A $4 12VDC motor with a gear on the end
- A 5V relay
Miscellaneous
- A PC speaker (any speaker capable of beeping is fine)
- A prototyping board of some kind, or breadboard
- Duct tape (you know it!)
- Soldering iron, solder, flux, and the like
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That's really neat, but is it really safe?
The only thing which I actually predict might happen is that the keypad gets vandalized (cut off with scissors, ripped off, etc) in which case I need to find a new authentication technique.
HOPE YOUR RESPONSE!!
I have to say though, RFID would be pretty amazing! If you get that working, I would be very interested to see your plans. As an upgrade to my current setup I am considering alternate methods (aka cheap hacks) for wireless authentication, but I'd have to do some math/experiments to figure out how they might work.
By random chance, I came across the datasheet for my motor! In caseyou're still interested in the properties of the motor, check it out:
http://www.activesurplus.com/files/mabuchi.pdf
I also am pulling from the farthest distance away from the axis of rotation of my door handle- my lever arm here is about 15 cm, which makes it much easier to pull the door-handle down. And, for added security, I added a small weight to the end of the doorhandle to aid in pulling in down.
All in all it's not a particularly powerful motor, but with the given setup it's capable of pulling the doorhandle down.
Thanks for checking out my project!
I do have an Arduino however, so I've played a bit with that. I justdon't have any projects I want to do ATM, since I have no optocouples (Iwant to build a CNC machine but I'm worried about blowing one or moreparts, so...).
Anyhow, I've got a few ideas for wireless that you could use.
#1) (I'm not sure about the legality of such a device operating - FCCregs and all that) You can use a cordless phone to send data - just popit open the handset, de-solder the mic and put some type of jack onthere. The audio comes out from the base on the phone wires, which youcan hook into anything you want. Alternatively, just write a program tocompare the audio of the button presses.
#2) IR - you can easily salvage an IR receiver (basically an LED, AFAIK)from an old VCR/TV/DVD player. Then just hook up the remote and storethe bits flashed by the remote. If you wanted to you could just writeyour own PIC based device to flash your own code(s).
#3) Garage door opener. Just get the proper communication parts.
#4) Wireless keyboard
There are probably plenty of other options (optical sensors, LEDs, laserpointers), but those are just a few.
Great instructable!
Nice work :)
I did the same thing back in the 70s when I was in college, except my roommate and I used a remote control taken from an old Motorola "Works in a drawer" color TV.
(This is several years before IR remotes. The term "couch-potato" hadn't been invented yet -- people were staying slim by getting up and changing the station every five minutes by hand. The lazier ones were using a notched broom handle to move the knobs....but I digress)..
This remote had four tuned rods inside it that were struck by a hammer when you pressed a button; two for volume up and down and two for channel up an down. No batteries required. A barely ultrasonic tone emitted from the struck rod would be received by the TV and a solenoid would mechanically turn the dial one notch per tone. We took out the receiver circuit and wired it to a bigger solenoid stolen from a old washing machine. The solenoid pulled a wire that turned the door knob, and a spring pulled the door open. Of course you had to remember to take the remote with you, but that was part of the fun. It had a rather eerie effect when a press of a button produced a loud clang from the solenoid and the door slowly opened with no one behind it. Great at Halloween!
That would give you a mechanically sound place to mount actuators and not have to put tape there.
The thing would be portable too, maybe marketable.
Unfortunately, in my specific case, I suspect that the door-hanger idea would not work-I have a large space underneath my door which could be utilized for a door-hanger, but unfortunately above the door there is very little room for something like that.
I will now fade into the shadows gracefully....