I have an office with electric gate, currently controled with a JCM GO SEND868-2 devise.
It looks to use rolling code.
My need : we are several people, and we want to use our smartphone instead of the remote to open/close the gate.
We want to know who opened/closed the gate.
So, I want to develop a small android app that will trigger a connected remote that will stay inside the office, and that will duplicate the signal of a real remote.
The app will be able to log who opened / closed the gate.
It looks like we can use Arduino as a connected remote, able to receive signal from our smartphone, and able to generate signal to open/close our gate.
Is it possible ?
I'm web developper able to build android app, but I never used electronical devices.
Do you know where we could find any tutorials for this ?
What do you think about this project ?
Thanks for your help
I agree with this. To emulate the remote control, one would have to crack the rolling code generation algorithm which is intentionally very difficult. Better then to have some device that interacts with the cell phone nodes and "pushes the button" on a real remote or (if available) wired interface to the gate.
This breaks the problem into two parts.
Implementing a server to which the phones can connect to command gate open/close. One idea would be the phones connect to a protected WiFi service in the vicinity of the gate and via app or web browser commands the gate operation. Access would be controlled by at least the WiFi PSK password and you could add additional layers if necessary such as an individual userid/password.
Having the server "press the button" on a remote. This is a pretty common problem in Arduino world, so there should be plenty of guidance available. Certainly a relay can simulate button make/break and it may be possible to do directly with an electrical signal or a transistor switch. Implementation is dependent upon characteristics of the remote and may require experimentation.
I don't know how to generate the rolling code.
But the company who installed the gate suggested me to buy new remotes.
So, I guess there is a way to add new remotes, and configure with the existing gate.
But I don't know how.
Ok good idea
So, I will keep one of my real remote inside the office, and plug an Arduino on it.
If I understand well, we should :
1 - Using an arduino and wifi component : code some script catching a message from the web, to execute an action by the arduino
2 - plug the arduino to the real device, to trigger the button on the existing remote.
About this last step, do you recommend me to sold wires directly on the remote electric card ? I'm afraid to burn the components.
Thanks a lot for your help on this project. Really helpfull !
plug the arduino to the real device, to trigger the button on the existing remote.
Yes, an Arduino output can be used with a base resistor and an open collector NPN transistor to effectively "push" a button (electrically). Don't forget to connect all the grounds.
Let me help you with what I learned when I had to replace the fob for my old pickup truck remote lock/unlock.
EACH fob transmits a specific code for that fob only. Along with a rolling coded number. Each time the button is pressed, the ID and the next rolling code is transmitted.
The central controller is programmed to ONLY accept a set of known controller id numbers. Each time a fob is used a list of the next 6-8 rolling security codes for that FOB is checked to see if the received code is in the list. If the code matches, the controller will generate a new list of potential rolling codes from that fob and unlock the doors or in your case, open the gate.
If the controller does not recognize the security code from your remote, you naturally press the button again and generate the next rolling code. If this happens enough times in a row, the controller will drop that fob/remote from it's list of valid devices and your remote is effectively dead until the controller is reprogrammed to again accept the remote id.
This is to warn you about the testing of your plan with an existing remote. Too many failed test will disable that remote.
To expand on Paul's post. When a fob is paired with a system controller, the serial number of the fob gets registered with system and the position in the rolling code sequence is synchronized between the fob and the receiving system for that serial number.
Automotive systems usually allow 2 to 4 fob serial numbers to be registered at a time and the receiving system recognizes these fobs only. It may be that your gate system allows registration of enough fobs that you can give one to each user and your problem may be resolved simply by buying enough fobs. If your number of users exceeds the number of unique fobs allowed by the receiver system then you'd have roll you own solution as you've proposed.
