PresencePi

Track how many people are present in a room using a laser sensor barrier attached to a Raspberry Pi counting people entering and leaving the room

Pseudo HTTP queries to adjust the counter

Get current people in the room

curl -i -XPOST "http://presencepi:8086/query?db=presence" -H 'Authorization: Token user:passwd' --data-urlencode "q=SELECT "Presence" FROM "People" WHERE "MotionSensor" = 'Eingang' GROUP BY * ORDER BY DESC LIMIT 1"

Increase current people in room by 1 + write control tag

curl -i -XPOST "http://presencepi:8086/write?db=presence" -H 'Authorization: Token user:passwd' --data-binary 'People,MotionSensor=Eingang Presence=$(CURRENT_PEOPLE_IN_ROOM + 1)i,Cumulative=1i,Control=1i'

Decrease current people in room by 1 + write control tag

curl -i -XPOST "http://presencepi:8086/write?db=presence" -H 'Authorization: Token user:passwd' --data-binary 'People,MotionSensor=Eingang Presence=$(CURRENT_PEOPLE_IN_ROOM - 1)i,Control=-1i'

Set current people in room to 0 + write control tag

curl -i -XPOST "http://presencepi:8086/write?db=presence" -H 'Authorization: Token user:passwd' --data-binary 'People,MotionSensor=Eingang Presence=0i,Control=0i'

Grafana dashboard example

Components used

• Raspberry Pi 3b
• Photoresistor GL5516 on light sensor module LM393
• Laserdiode module 15 * 6 mm, 5 V
• some case

Complet setup