Looking for a programmable garage door opener IC. - Page 1
Forum section: electronics / beginners

author: cfrolander
author_rank: Newbie
timestamp: April 05, 2011, 03:22:08 pm
content: I've looked and looked, and I'd like to find an IC or some method that I can use to program a garage door opener to open most residential openers. I imagine there's some IC of some sort out there since most newer cars have some sort of programmable garage door opening system on them, I'm just not able to find anything. Does anyone have any insight on how this might be done? I can't just buy a retail programmable remote and just integrate it into my project, I need to build it from parts.

author: Zero999
author_rank: Super Contributor
timestamp: April 05, 2011, 05:59:44 pm
content: Why are you a thief?Any decent door opener should change the code every time making it almost impossible to crack.

author: cfrolander
author_rank: Newbie
timestamp: April 05, 2011, 08:12:01 pm
content: Quote from: Hero999 on April 05, 2011, 05:59:44 pmWow that's a pretty outrageous claim, but yeah thanks for the support...Quote from: Hero999 on April 05, 2011, 05:59:44 pmThey almost all do this, I'm not sure the protocol but I'd imagine some sort of token authentication. I also know it's possible to program a new device to the garage door, for instance my Infiniti I can program to open my garage door. I don't mind having to use the method Infiniti does and have your original opener there to program with, I'm essentially trying to design a garage door opener that is embedded in vehicles that otherwise don't have them built in.Here's a car that can do this, and a demo on how to use it. I'm trying to accomplish the exact same thing that comes standard on millions of cars worldwide... Also note that most garage doors have to register the devices which are allowed to open, which usually involves hitting an authorize button on the door then pressing the button in the car again. This is fine.

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 05, 2011, 08:34:00 pm
content: HomeLink is made by Johnson Controls. It sounds like a proprietary system. I've never seen a chip on its own that would do this. I've been wrong before, but I doubt there is one.

author: cfrolander
author_rank: Newbie
timestamp: April 05, 2011, 09:05:52 pm
content: Quote from: TheDirty on April 05, 2011, 08:34:00 pmActually that helped very much, I was able to look up a bit about the technology they use. I've found that the Homelink devices use Rolling Code security, which picks the next token based upon pseudo-random number generator known by both devices, and any of the next 256 entries are accepted as valid to compensate for presses while one device is out of range. It also seems that this is the same technology used for car keyfobs which is nice to know. I see thatTI makes a a chip(PDF!) that can encode and decode the 40-bit tokens used for authentication. I've still got much more research to do, but thanks very much for the help so far! Sometimes I just need some prodding in the right direction

author: TheDirty
author_rank: Frequent Contributor
timestamp: April 05, 2011, 09:35:40 pm
content: It may all be in one standard now. My understanding is that it conformed to a few different protocols, using whichever one is appropriate, but there is some open access guideline that makers of garage/gate openers generally conform to now. Almost all of them use rolling codes of some form.There are plenty of microcontroller based rolling code projects out there. At least I seem to remember them from a few years ago.

author: insurgent
author_rank: Regular Contributor
timestamp: April 05, 2011, 10:02:41 pm
content: Homelink apparently uses Microchip's KEELOQ. You might be able to find some chips here to make a compatible device:http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=2074&redirects=keeloqFor fix-code units it looks like the Princeton Technology PT2262 encoder is commonly used.I haven't seen a chip that combines all types onto one unit but there may be something from Microchip that does.

author: Zero999
author_rank: Super Contributor
timestamp: April 06, 2011, 05:06:28 pm
content: Quote from: cfrolander on April 05, 2011, 08:12:01 pmYou need to read posts more carefully, it was a question, not a statement.QuoteI would've thought they'd be pretty similar to a car security system.

author: ziq8tsi
author_rank: Regular Contributor
timestamp: April 06, 2011, 05:57:20 pm
content: Quote from: Hero999Not really. You needed at least a comma after "Why".