Question

[adrianmihalko]

Dear denvera,

I successfully installed the DSC node server.

Now the hard part (at least for me):

This is a front end server written in Node.js that talks to either the dscmod kernel module or an ESP8266 based WiFi module interfacing to the DSC KeyBus via a level shifter.

1. I found your other project the DSC KeyBus for rPi. How I modify the default.js to work with rPi setup? In the default.json file I see: "mode":"socket", "port":10242, "code":"1234".
2. It is needed to connect 12V +- trough level converter, or it is enough to connect Green/Yellow wires without level converter? What do you think, it is possible to pull wires from the keypad itself and use these with rPi? My alarm is on a hard reachable place, and this way would be easier.
4. You mentioned ESP8266, that's would be great. Do you have any code, example how to make your server work with ESP?

Regards,
Adrian

[denvera]

Hi Adrian,

Thanks for checking out the project!

1. You can set the mode to "dev" instead of socket, which will cause it to try and read from /dev/dsc_bin, which the kernel module creates. You can just ignore the port option, as it isn't used for "dev" mode, and "code" is the arm/disarm code, used for scheduled disarm tasks.
2. You will definitely need to use a level shifter with the Pi, or at the very least a resistor divider if you just want to read the bus. I strongly recommend a level shifter though. Its definitely possible to just pull wires from the keypad, the bus is designed to be multidrop so this is perfectly doable.

3/4. I haven't made the ESP8266 code available yet, it could use a bit of a cleanup.

Please let me know how it goes, I'm keen to hear if it works for you.

Kind regards,
Denver

[adrianmihalko]

Thanks for the fast answer. I ordered a Raspberry Pi.

I have a few ESP8266 modules and these are really great devices and they are very small compared to a rPi. It would be great if you later released a code for this.

One more question, an user on Avrfreaks replied me:

"Keep in mind most DSC panels will not recognise your 'virtual keypad' unless it has a unique address AND this address has been registered in the panel. The only way around this is to use the same address as a registered keypad, but physically remove the real keypad before you connect your device."

Do you have any experience with this problem? I have an older DSC PC585 system, and as I checked the manual the keypads are really registered in the panel /unique address/. Or the code is not acting as a keypad?

"Now I did a little snooping around as this subject has been asked all over the internet, and I noticed that DSC has several modules that would allow you to connect your AVR project through it's usart interface to the Keypad bus. They even provide rather decent documentation on the commands too."

...like the IT100, Envisalink modules. They advertising itself as a PC5400 serial reader module.

[denvera]

The Linux kernel driver is capable of emulating a keypad. I do this for my current setup, and I've not had any problems, both the virtual and physical keypads work fine so far together.

[rogueturnip]

Thanks! Where in the code do you do your registration of the keypad in slot one?

[denvera]

The kernel module does not do any registration, it just sends back key presses, I suspect the keypad slot allocation is only for supervision (see DSC manual).

Occasionally the main panel will send out a 'discovery message' (0x11 if I remember correctly), and check that the keypads respond in the slots allocated.

I have two physical keypads so a 0x0f is returned (2 bits for each keypad set low), as below:

PANEL: 0x11 0x00 0x0A 0xAA 0x0A 0xAA 0xAA 0x2A ('discovery' message)
CLIENT: 0xFF 0x01 0x0F 0xFF 0x0F 0xFF 0xFF 0x3F (keypads responding, each pulls the two bits corresponding to their 'slot' low).
(I call any non-panel devices, sending data back to the panel on low clock edges "client" devices, as above)

If the main panel is expecting a response in a supervised slot, I'd assume it just indicates some trouble condition.

I've not had any problems with the panels not responding to keypresses from 'virtual keypads' though, the main panel happily processes keypresses. I don't even think the keypress messages contain the keypad slot.

I edited my previous comment, as the kernel module doesn't actually send anything other than the keypress.

[edouardkleinhans]

Hello, thanks for your code. Do you have any news regarding ESP8266 based WiFi code ?