Development of circuitry and software for an autonomous telemetry device

Job ID: 35685223

Budget: $1,500 – $3,000 USD

Task:
Development of circuitry and software for an autonomous telemetry device (hereinafter "Sensor") that measures and then transmits to a local device (hereinafter "Master") the received data via the LoRa wireless protocol.
Sensor is powered by a lithium-ion battery type "18650", Sensor includes sensors: weight, temperature, humidity, atmospheric pressure, sound, gyroscope, radio module. The task of the Sensor is to measure the data from the sensors at specified intervals and send the obtained values to the Master.

Description of work:
The Sensor measures and transmits the following data:
• Weight, temperature, humidity, atmospheric pressure, sound (FFT), battery voltage.
• Determination of position in relation to the horizon using a gyroscope.
• Wake up and send an alarm when unauthorized movement.
• Wake up and send an alarm when there is a significant (more than 10%) weight change.


Technical part and setup:
• There are 2 ways to calibrate and adjust the Sensor:
1) Using the service button, switch to the calibration mode using the LoRa wireless protocol.
2) Wired setting via UART port terminal.
• The setting includes: setting the serial number of the device, receiving current data from sensors and batteries, calibrating scales, setting the time intervals between sending data in minutes.
• The protocol of exchange with the Master (the gateway serving the device) will be agreed separately.
• Two-way communication over LoRa.
• After waking up, the Sensor should listen to tine line and if it is free to send data.
• Receive confirmation after sending.
• The number of attempts to send 3 with an interval of 1 second after going to sleep for a specified time.


Anticipate for the future:
• Connecting an additional module to work via BLE: the additional module will contain temperature, humidity, sound sensors, the Sensor will serve as an intermediate node for transmitting the received data to the Master.
• Real time clock module for setting wakeup and sending data timers, marking messages with data sending time.
• Remote software update.
• Connecting an additional GPS module with sending coordinates to the Master in case of unauthorized movement and / or significant (more than 10%) weight changes.


The composition of the equipment:
• Main microcontroller Ebyte e77-900m22s
Built on the STM32WLE5CCU6 chip, contains a LoRa module on board.
https://www.cdebyte.com/products/E77-900M22S
• Temperature, humidity and pressure sensor BME280
https://www.mouser.com/datasheet/2/783/BST-BME280-DS002-1509607.pdf
• Microphone Digital SPH0645LM4H
https://cdn-shop.adafruit.com/product-files/3421/i2S+Datasheet.PDF
• ADC for load cell HX711
https://cdn.sparkfun.com/datasheets/Sensors/ForceFlex/hx711_english.pdf
• Gyroscope MMA8452
https://www.nxp.com/docs/en/data-sheet/MMA8452Q.pdf