OHS is open source based burglar alarm and automation platform. It can work as new alarm gateway, or it can replace your old alarm panel. OHS can use any wired 12V sensor, PIR, smoke or reed switch. It has Web interface that is used to set it up. OHS has GSM modem that is able to send SMS or page you. It has radio interface for environmental sensors. OHS is self-contained, it does not need any cloud service, only optional SMTP server for emails, or MQTT server to publish collected sensor data.
Tuesday, October 28, 2014
Power supply
In last post I have mention the power supply is too strong. By checking the documentation again I can say it way to strong, 60W. Originally I have designed my own power supply with transformer, rectifier and some switchers to deliver 13,8V for battery and 5V for GSM. Together with some led signalizing the status of mains and battery. But later I have considered it rather inefficient for 24/7 running.
Developing a true switching power unit is rather expensive, beside I have no previous experience, and I'm just a hobbyist. And my favourite producer
of power supplies had a nice choice of 13,8V units. I have chose PSC-60-C, the one with enclosure. It has two outputs, one for battery charging and one to power for main board. It has also open collector outputs for signals when the AC is off, or the battery is reaching low level(11V). Then it also cuts of the battery when it reaches 10,5V. Just everything I wanted and it has 84% efficiency. Also it looks nice and shiny in the box :)
Labels:
hardware,
mainboard,
power supply
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