Imported from GitHub: hierle/letterbox-sensor · commit 9942fb8 · license GPL-3.0

Description

LoRaWan letterbox sensor

README

LoRaWan EU868MHz Letterbox Sensor

New version letterbox sensor v2 available here: https://github.com/hierle/letterbox-sensor-v2 :)

sensing letters in your letterbox via IR diode pair, sending out status via LoRaWan/TTN based on Attiny84, RFM95W, HSDL9100, powered by a CR2032 battery.

This is basically a clone of the heise ct briefkasten sensor project https://www.heise.de/ratgeber/IoT-Netz-LoRaWAN-Briefkastensensor-mit-hoher-Reichweite-selber-bauen-4417179.html https://github.com/jamct/radio-mailbox

Contents:

• ./PCB/ : kicad PCB files
• ./calibrate/ : calibration sketch to adjust the poti for letter distance
• ./letterbox_sensor/ : lora letterbox sensor sketch
• ./misc/ : payload decoder, sample http integration cgi

Compiled with platformio, hex flashed to attiny with ArduinoISP

Changes:

• created SMD PCB
• onboard 868MHz PCB antenna after TI document http://www.ti.com/lit/an/swra227e/swra227e.pdf
• switched MISO/MOSI lines of RFM95
• Attiny pin renumbering 0...10 -> 10...0
• sensor pin naming changed from 8 -> A2, otherwise no ADC reading
• added basic temperature reading from RFM95
• added sensor raw value, voltage, temperature in lora package

BOM (digikey.de):

Part number	Description
ATTINY84A-SSUR	IC MCU 8BIT 14SOIC
HSDL-9100-021	PROXIMITY SENSOR
RFM95W-868S2	RF TXRX MODULE
3314G-1-105E	TRIMMER 1M OHM
BU2032SM-FH-GTR	CR2032 COIN CELL HOLDER
HLE-103-02-L-DV	CONN RCPT 6POS
AA3528LSECKT/J4	LED ORANGE
CRGCQ1206F33R	33R 1206
CRGCQ1206F220R	220R 1206
LQG18HN1N8S00D	IND 1.8NH 0603
GRM1885C1H2R7CA01D	CAP 2.7PF 0603

An extended web ui by Peter is available here: https://github.com/pbiering/letterbox-sensor-web

Have fun!