Overview

This is a private repository for my project at WISEST lab during Summer 2018 as an undergraduate research assistant. This project is a dairy IoT, using chiefly Arduino (C++/C) and MATLAB. MATLAB is responsible for gathering data from experiments and finding calibration coefficients. Arduino programs a microcontroller board. The goal is to monitor the core temperature of livestock and to wirelessly send the data through the internet.

Components used

1. Adafruit Feather M0 LoRa MCU x2
2. ESP8266 WiFi Module
3. Priority1 RFIDRW-E-TTL Reader with an antenna
4. Bio temperature sensors
5. UBBL24-Fl-TH 7.4V 4800 mAh Batteries
6. MCP1702-3303 LDO
7. VN4012 NMOS
8. 1 uF Capacitors
9. Clipping Diodes (not used previously but recommended on RX-TX)
10. Wires
11. Prototype board
12. Header pins

Useful electronic devices

1. Soldering station
2. Power supply
3. DMM
4. Oscilloscope

Softwares used

1. Arduino IDE
2. Matlab R2018a
3. Altium Designer
4. Git
5. Microsoft Office
6. Google Chrome

Libraries used

1. RH_RF95 LoRa library
2. RTCZero Timer/Low power library
3. SPI (may not actually needed)

Codes (inside Codes folder)

1. LoRa_RX_Multi HUB's code
2. LoRa_TX_RTC_V2 Device's code
3. LoRa_TX_NMOS Debugging code without a sleep mode
4. Online_Matlab_Code Thingspeak code

Schematics

1. High-level Schematics
2. Detailed Schematics of a Hub
3. Detailed Schematics of a Device

Useful resources

1. ESP8266 AT Command
2. Adafruit Feather M0 LoRa schematics
3. Datasheets of components
4. Some files in Extras folder

TODO-Issue list

1. Change a number of devices connected to the hub.
2. Change a period of the reading.
3. Collision handling could be better by echoing some parts of data sent from a device to a hub back to the device.
4. Floating pin on a reader when NMOS creates an open circuit will need to be addressed. Now the current likely goes through RX-TX, which is not good.
5. There is still a grounding problem with a device and it can pick up a wrong part of data to be sent or receive a wrong data.
6. Sending all reading data to the hub might be a good idea than processing some of them on a device. This comes at a cost of power consumption.
7. Make a solid protocol between devices and a hub and across all devices.

Words of caution when integrating parts

1. Do not connect V+ and GND of a battery. It could explode.
2. Be careful when using a DMM. Do not let a probe touch any 2 pins. This creates a short circuit.
3. Unplug or turn off a power supply first before removing any components.
4. MCU and IC are sensitive parts. Be especially careful when connecting them and notice the Vin of them.
5. When doing a hardware debugging, start at which the problem most likely happens.

Setting up a device

1. Change period, LoRa signal power, and other variables if needed.
2. Program a device. Double-push the reset button and wait for a LED to blink, if needed.
3. Be careful when messing with Sleep mode/Standby mode of MCU. It might brick the device.
4. In a standby mode (sleep mode), you cannot really use serial communication with a PC since the sleep mode cut the communication.
5. If needed, use LoRa_TX_NMOS to debug a device. That program does not have a sleep mode in it, while still printing a reading through a serial communication.

Setting up a hub

1. Change a number of devices, sample per wake or other variables if needed.
2. Program a hub.
3. The LED blinks every time a hub gets any inputs.

Setting up a Thingspeak.com

1. Create a channel that takes inputs from a hub.
2. Read data using readAPIkey and channelID.
3. Use Matlab Analysis to analyze the data.
4. Post data to a different channel using writeAPIkey and channelID.
5. Edit charts and set public view.
6. If needed, data can be exported in a CSV file.

Charging batteries guide

1. Use a power supply and set a constant voltage (max voltage) and a constant current (1 A recommended)
2. Do not a power supply directly to a battery (for safety reason?)
3. Use a prototype board and a JST connector to create a charging device.

Troubleshooting guide

1. Use a DMM to test a voltage at any points.
2. Use an oscilloscope to check UART communication.
3. Measure an impedance of an antenna.
4. Print out a reading and such on a serial communication.
5. Look at inputs from a hub to Thingspeak.
6. Check Thingspeak code.

Locations of possible problems

1. Check the antenna connection.
2. Check the power connection and power level.
3. Check the software problem.
4. Check the prototype board connection.

Final words

This project was not possible without Prof. Kim's, Jingjie's, Hanwook's and others' helps. I really appreciate all helps and advices I received and I am grateful to be given a trust to handle this project.

Contact: Anapat Chairithinugull Email: chairithinug@wisc.edu Cell: +1 6087729985