Instructables
Picture of An Electronic Door Opener
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.
 
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Step 1: Parts list

Picture of 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

mkovtchega3 months ago

you should post this instructable to DIY university contest!

dnicol19 months ago
Hi Colin. We spoke last year about a project i am working on. I would like to touch base with you now that i am back on it. Are you interested?
dnicol11 year ago
Well if you know anyone i will pay big money to get it done asap. Thanks
dnicol11 year ago
I understand the time it takes to get it perfected... Totally makes sense. If you can put me in touch with that contact anyway i really need it... Even if a quick meeting with get me on my way. Thanks !
dnicol11 year ago
Hi Colin timeline is this weekend. I need a simple 12vdc relay to stay energized for 5 to 10 secs.
I heard a 555 timer is the way. I have the parts ( i think) good money for someone who knows this better than i. Also need a signal from a mic amped up to trigger same relay. My number in Toronto is 647 984 4314
colin353 (author)  dnicol11 year ago
Sorry, but that seems like a bit too optimistic of a timeline for anyone I know. To get a circuit working and reliable takes a long time, particularly because you typically need to order parts several times and do a couple of iterations to get everything perfect!

Just as a piece of advice though, a 555 timer will do the job, but it's an ancient analog part. You might be better off getting something like an Arduino, which can simplify things like making the timer more accurate. It can understand things like a microphone input, which would be much more challenging to handle in an all-analog circuit.

Anyway, good luck with the project!
dnicol11 year ago
Hey Colin. Great projects. I'm looking for someone in Toronto to do some circuits for me with 555 Timers, 12VDC relays etc for cash asap. Do you do that ? If not do you know someone?
colin353 (author)  dnicol11 year ago
Hi! I think I might know somebody who could help you... could you elaborate a little bit on what you're looking for, and your timeline?
nodoubtman2 years ago
Woww man!!!... just the circuit to turn on the motor is the most complicated part.. :S ;o congrats!!!
davila12 years ago
Can I us an arduino, by th way , great instructables, but u should upgrade the schematic quality
geekazoid5 years ago
 Go Toronto!
That's really neat, but is it really safe?
colin353 (author)  geekazoid5 years ago
Well,  I guess I didn't put a lot  of thought into safety. Presumably if somebody saw me enter my key code then they could get into my room at any time without me knowing, which would be unfortunate. I consider that to be the only real security vulnerability though, because a brute force attack on the outside is implausible and too time-consuming, and I don't predict that the keypad will show signs of visible wear on the buttons.

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.
i can help you with that just send me all the schematics with more quality and i can make you an authentication technique

HOPE YOUR RESPONSE!!
keep the keypad on with packing tape :)
gomas2113 years ago
HEY POST THE NEW IMPROVEMENTS WITH THE NEW CODE
palabuto4 years ago
awesome project man.Can you send me this project circuit at my email at mfdh_90@yahoo.com or at my instructables accound.i really need this project for my class.thank you.
colin353 (author)  palabuto4 years ago
I scanned some schematics: http://www.flickr.com/photos/colin353/4385411009/ Good luck with your project!
ethanzonca5 years ago
nice, I'm thinking about doing something similar for my dormroom door (maybe with rfid), the biggest issue is the door handle actuator. Your duct-tape approach might be what I end up doing :D
colin353 (author)  ethanzonca5 years ago
Actually yes, my original plan included RFID, but I decided that RFID readers are pretty expensive. My entire hack cost next to nothing, so I decided to be cheap.

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.
I just got a nice $30 rfid reader + breakout from sparkfun, I'll probably install it sometime next week and post some photos... I already have a belt-driven door opener setup that works quite well, currently running with an arduino.
Thats exactly what I was planning for my Dorm door... however I am putting a twist on this keypad entry... look for an instructable in the near future...
hey check this video out http://revision3.com/systm/rfid you could use somin like it for a door


If I put this in, my roommate would break it out of spite.
Speedmite5 years ago
Now this is pretty cool, but it would be even cooler if it also openedthe door too.
cupnoodles25 years ago
hello im doing a project just like urs but i have a problem, ur motor goes forward to pull the thing and open the door and the the spring pulls the string back? o do u reverse the thing so it lets the string away? thanks great project btw
hey sorry one more thing i have had a hard time trying to look for a motor strong enought like to pull my door thingy open, ive tried many motor i mean i have a collection -.- i even tried some geared ones but none seem to have enought torque so now am asking, did u take that one from a 12v blender? thanks :D
colin353 (author)  cupnoodles25 years ago
cupnoodles-

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
colin353 (author)  cupnoodles25 years ago
haha, no, it did not come from a 12V blender. The critical thing to note about my setup is the fact that I am winding the string around a shaft of very small radius. This means that I have to make a large number of turns to get the door handle down all the way. This way, torque requirements are reduced.

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.
colin353 (author)  cupnoodles25 years ago
In this project, the motor is not reversed. The door handle has a natural tendency to return to its normal position, and so when the motor turns off, the door handle unwinds the string back to its original state.

Thanks for checking out my project!
app05 years ago
 Kool, gonna do something like this with my old pc
srilyk5 years ago
This is a pretty cool project. I really want to learn more about PICprogramming, but I need a programmer to program with! (And some PICs...)

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!

=SMART=5 years ago
Great soloution !
Nice work :)
kmpres5 years ago
Great work, and when you leave the University, the tape and stuff comes off the door without a trace.  Excellent!
 
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!
colin353 (author)  kmpres5 years ago
Wow, that's amazing! I would have been completely unable to build this if I didn't have access to microcontrollers. Very impressive that you could do it all in analog!
sergiuung5 years ago
awesome, but you'd better fit everything into a box :D
Kaiven5 years ago
That is cool stuff! I have no need for it, but still an interesting project, well done!
colin353 (author)  Kaiven5 years ago
thanks!
you know you could get a couple of those "clip on hanger holders" for doors, or the things used to hang christmas wreaths, and put one on the top of the door and the bottom, and a tensioner between them (screen door turnbuckle?

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.
colin353 (author)  ProfessorJWN5 years ago
Actually, that is a very smart idea, and I never even considered that. I do consider the duct tape to be inelegant and also mechanically ineffective. I plan to replace the duct tape with velcro, which will hopefully deflect less (presently a potentially serious design flaw) when the motor is running at full power.

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 am humbled by your Hack-A-Day featuredness.  Well done.


I will now fade into the shadows gracefully....