Garage door opener for 2 doors with 8 remotes - Page 1
Forum section: electronics / projects

author: Swake
author_rank: Frequent Contributor
timestamp: April 02, 2020, 04:11:41 pm
content: Hi,I have to add remote control to 2 garage doors with 8 users. Ideally even 3 doors and expandable number of users.- It must be possible to delete one of the remotes (for when it gets lost or stolen for example) without having to reprogram all the remotes or having them at hand.- Something like a rolling code security system or similar. Not nuclear site grade stuff but definitively not a single code or a fixed signal.- 20m/60feet reach or better.We found a commercial solution that costs more than the doors themselves altogether, as we are on a budget that is not an option.I was thinking of making something with an Arduino or ESP32 as a lot of different remotes are available on the well known Chinese sites, but unfortunately I couldn't locate a system that fits the above specs.Do you have suggestions?

author: SeanB
author_rank: Super Contributor
timestamp: April 02, 2020, 04:44:00 pm
content: how about this, though I do not know if it is available by you. 3 channels, code hopping and you can delete individual remotes easily, plus plenty of memory to store transmitters.http://www.centsys.co.za/upload/product_link_files/CS38_1176.D.02_0001_1_SupaNova_Brochure.pdf

author: voltsandjolts
author_rank: Unknown
timestamp: April 02, 2020, 04:46:55 pm
content: Quite some time ago my garage door opener failed and I took the opportunity to learn about keeloq.I managed to dig up some code snippets from depths of the internet and got it running.https://www.eevblog.com/forum/microcontrollers/microchip-keeloq-classic-new-firmware-for-garage-door-receiver-new-fobs/IIRC the micro eeprom stores a unique code for each paired key, so you could delete as appropriate to remove a key.I think this was done on MPLAB and free XC8.Might take a bit of mucking around to get it compiling on MPLABX now.

author: rvalente
author_rank: Frequent Contributor
timestamp: April 02, 2020, 05:15:45 pm
content: Quote from: SeanB on April 02, 2020, 04:44:00 pmA picture of board with a PIC 16C57, C! Uow... and a key of older 80s fiats, that was nostalgic!

author: Swake
author_rank: Frequent Contributor
timestamp: April 02, 2020, 07:23:37 pm
content: The cheap fobs on aliexpress seem to be all the same. Some are claiming to be HCS301 'compatible', actually these have a list of master keys stored from different brands and when you clone them from another working fob these lookup the correct master key and activate that one.The difficulty I have is finding fobs with different identities. Or fobs that I can program with my own algorithm. Someone DIY minded must have been here before me

author: Swake
author_rank: Frequent Contributor
timestamp: April 02, 2020, 07:25:41 pm
content: BTW I found some Keeloq code here:https://github.com/franksmicro/Arduino/tree/master/libraries/Keeloq

author: ozcar
author_rank: Frequent Contributor
timestamp: April 02, 2020, 08:46:53 pm
content: Quote from: Swake on April 02, 2020, 07:23:37 pmIn another thread here (https://www.eevblog.com/forum/chat/universal-fixed-and-rolling-code-remote-control-duplicator/) I mentioned a couple of those fobs that appear to have a selection of manufacturer keys programmed into them that they can select from. Of course they don't use standard Keeloq encoders like the HCS301 - the ones I looked at were based on STM8L processors.I speculated on the possibility of reprogramming them, but I did not try to do that. Besides your own algorithm, you'd have to contend with taming the radio chip. Similar fobs that work on only a single frequency might be easier to re-purpose.Not sure what you mean about "fobs with different identities". Those "universal" fobs I looked at appeared to generate random serial numbers. I have sometimes wondered if the makers of the non-universal "compatible" remotes, that may well use encoders like HCS301, might get lazy and make them all with the same serial number programmed into them. However, that could cause trouble if somebody bought a few and tried to use them all on the same receiver, so I would assume they would not do that, but perhaps I am wrong.

author: voltsandjolts
author_rank: Unknown
timestamp: April 03, 2020, 01:02:20 pm
content: Quote from: ozcar on April 02, 2020, 08:46:53 pmIIRC Keeloq fob ICs (HCS301 etc) have a crypt secrect code (encyption key derived from a secret manufacturer code*) and the fob 'serial' number.* All of your system components must use a key derived from the manufacturer secret code.This is what allows them to charge an-arm-and-a-leg for a new button remote.With the code at my link aboveyoubecome the manufacturer, with your own secret code.

author: madires
author_rank: Super Contributor
timestamp: April 03, 2020, 01:19:18 pm
content: All the garage door openers and add-on remote controls I worked with so far allow only to clear all fobs, not specific ones. It makes sense if you think about it, because you would need a display for selecting the fob and a way to distinguish them. That's a feature you get with expensive professional access control systems.

author: voltsandjolts
author_rank: Unknown
timestamp: April 03, 2020, 01:21:24 pm
content: Thats right, but with the code at my link above you have the option to do what you want, e.g. display to select a fob for deletion.

author: ozcar
author_rank: Frequent Contributor
timestamp: April 03, 2020, 07:48:57 pm
content: Quote from: voltsandjolts on April 03, 2020, 01:02:20 pmWell, yes, I know that, but...Swake mentioned difficulty finding fobs with different identities. For ones using Keeloq, the identity would be the serial number, and I would have thought that it would be difficult to find fobs with thesameserial number (except for the far-out possibility that I mentioned of a maker getting very lazy).Nor do I know why fobs with the same identity would be useful, as that would surely make it difficult to erase one of them only from the receiver (besides the fact that using two fobs with the same identity on the same receiver could be problematic).Of course, if you make your own receiver, then you are free to come up with some way to erase only one of the fobs. You don't have to make your own fobs, but you'd have to know, or be able to derive, the fob keys, or else reprogram the fobs (if possible) with your own keys. Well, for Keeloq classic you could totally cheat in the receiver, and just ignore the encrypted portion of the transmission (all you need to react to a button press is contained in the non-encrypted part). That would, of course, totally defeat the purpose of having a rolling/hopping code, but, would you believe it, I have found "universal" receivers that do exactly that.

author: Peabody
author_rank: Super Contributor
timestamp: April 03, 2020, 08:11:29 pm
content: My opener is very old, and it is triggered by shorting the two receiver terminals. Long ago I replaced the original Sears remote with a third party addon which works the same way. This has a fixed key which is set by dip switches on both transmitter and receiver, with no provision for multiple transmitters each with its own key. Of course this is the old style - before rolling codes and such. But up to a point it would be possible to use multiple transmitter/receiver pairs, each with its own key, with all of the receiver outputs in a wired-OR setup to trigger the door opener. To disable one transmitter, you would just unplug, or change the key of, its receiver. Anyway, the point is that if you're talking about three-buck arduinos as the receivers, it might be easier to just do multiple copies, one for each transmitter, instead of jumping through hoops making one of them super intelligent. But that would depend on how the door opener is actually triggered.

author: voltsandjolts
author_rank: Unknown
timestamp: April 04, 2020, 08:21:25 am
content: Quote from: ozcar on April 03, 2020, 07:48:57 pmJust reprogram the fob HCS300/301 with your own manufacturer code and serial.Then, of course, use the same manufacturer code in the Keeloq classic receiver code, which I linked above.Job done.

author: ozcar
author_rank: Frequent Contributor
timestamp: April 04, 2020, 09:49:35 pm
content: Quote from: voltsandjolts on April 04, 2020, 08:21:25 amThe fact that you get to choose the fob serial numbers maybe makes it a bit easier to keep track of them. For example, you could give them a 5 character "name", using a 5-bit character set (enough for single-case alphabetic).