RDMA-PCB

Rpi Dead Man Alarm - PCB and 3D case - Occupancy Monitoring - Raspberry Pi hat

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23-RDMA-Case-03.jpg

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Video of it in action

V 1.0 29/05/2020 - Initial Release

Ready to use PCB Board

PCB Design Files / gerber files

3D Printed Case design files / STL

FYI Gerber files are in the release section

more pictures in the wiki

18-RDMA-Wiring-01.jpg

10-RDMA-FrontR-V1.0.jpg

15-RDMA-Back-BoardOnly-V1.0.jpg

09-RDMA-schematics-v1.0.jpg

1 to 1 scale

please use PDF version, and print to scale

PCB features

Step down DC DC regulator (12v will power both the pi and PIR sensor)
Input has a self reset fuse, and reverse polarity protection.
Physical on/off switch when powered via 12v
Back power protection to allow pi to provide power.
RTC clock
Segment display (to display time left before alarm is triggered)
Ability to trigger 3 X 5V object (e.g buzzer or lights) (will probably only populate one for the buzzer)
The above trigger can be set to either 5V or 12V.
Built in buzzer (to alert operator 1 min before alarm is triggered and SMS are sent out)
1-wire rail (possibility to add a number of DS18B20 temperature sensors)
2 physical button, one to manually reset the timer, or if hold for a few sec, will extend the timer once. Other button is to shutdown/unused.
Ability to add external buttons.
1 configurable status light. (on when the service is running)
All button, including PIR input has a physical denounce to eliminate noise/false alarm.
EEPROM as per pi hat requirement (will probably not populate)
Screw terminal for all connectors. No crimping required.

A 12V , 1A PSU should work, however, to be on the safe side, use a 12V, 2A PSU

if the service is not running after restarting, GPIO 8 would be on, which would make the buzzer turn on. to turn it off, use the following.

gpio readall
gpio -g mode 8 output
gpio -g write 8 0