1-wire with motion detector or reed contact

[Christoph Wempe]

Does anybody use a motion detector or reed contact with 1-wire?

I have the following problem.

I use the OW-SERVER-ENET (from Embedded Data Systems) to access my 1-wire bus.

The motion detector and reed contacts are connected to "D2C" modules (http://www.embeddeddatasystems.com/assets/images/supportFiles/manuals/D2C.pdf).

Depending on the amount of connected devices it takes >10s to pull the information from all devices and start again.

If the motion detector or reed contact switches its state back and forth in less than these 10 seconds the OW-SERVER cannot know the state had changed in the meantime, because it is back to normal.

Is there any solution for this problem?

Maybe one can delay the back-switching with some electronic module.

I know this is not really openHAB related, but maybe other users have faced the same problem.

[Daniele Casti]

Hi! This is one limitation of 1-wire bus. You have a bought one motion detector with a adjustable delay.
Try this http://www.simplelabs.co.in/328-thickbox_leometr/pir-sensor-motion-detection-sensor.jpg

[Patrick Könemann]

I had a similar issue with my 1-wire experiments with a RasPi: using the onboard 1-wire controller was unusable because it has a delay of at least 90sec until it realized that a reed contact (via an iButton) was missing on the bus.

Then I used another 1-wire controller [1] which is working with owfs [2] where I could successfully configure the period of checking which devices are connected to the bus. A period of 1 second works fine, so this setup is working for my reed contacts.

Hope it helps.

Patrick

[1] https://www.abelectronics.co.uk/products/3/Raspberry-Pi/27/1-Wire-Pi

[2] http://owfs.org/