Title: Low Cost Harmful Algal Bloom Monitoring
Recap: This is my second post. Last week, I gave a brief introduction on what is HAB (Harmful Algal Bloom) and its impact (economic, environmental and health). I also gave its cause including the role of climate change (temperature and Carbon dioxide) in frequent occurrence of HAB. On the technical side, I gave an overview on how the system would be setup and look like. Basically the system can be divided into two subsytems: the wireless sensor node part ( enclosed in a buoy and deployed in coastal water) and the base station (located inland near the coast).
For this week's post, detailed information on sensor node.
WIRELESS SENSOR NODE:
A. Microcontroller:
16 bit MSP430FR5969 is the main microcontroller for the wireless sensor node. This MCU has two UARTs: one can be used for the transceiver and the other for sensors. Since I will be attaching multiple sensors to a single UART, I will be using a 74HC4052 Mux/Demux IC capable of connecting up to four asynchronous serial UART devices into one single microcontrollers UART RX/TX pins.
B. RF communication:
Data acquired by the node through its sensors will be sent to the base station through RF transceiver and I will be using TI's CC110L transceiver. Ideally, transceivers with longer range and capable of mesh topology should be used considering node will be placed far from base station and my ultimate goal is to build and deploy network of wireless sensor nodes ( if I have enough fund or if our local government will give 
). So for a single node project, CC110L will do with limited budget.
C. Power source:
3.7V lithium ion battery with charging circuit and solar panel.
D. Sensors:
1. Carbon dioxide sensor
- with analog interface and using MG811
2. Temperature and Humidity sensor
-measure air temperature and humidity using SHT10 sensor
- Humidity Ranger:0-100%RH
- Temperature ranger: -10-80℃
- Humidity accuracy:±5.0%RH
- Temperature accuracy:±0.5℃
3. Submersible temperature sensor
- digital output temperature probe with UART interface
- accuracy +/- 1C operating at 3.1-5V
4. Color sensor
- color probe can be used to monitor slowly changing events like algal bloom
- outputs 8-bit format R,G,B data
- outputs light intensity in lux
- operating at 3.1-5V
- UART interface
5. Dissolved Oxygen sensor
- during algal bloom, D.O. level drops and this will be a good indicator
- output range of probe is 0-20 mg/L
- interface either UART or I2C
So, that's it for now.
Next week, I will be posting detailed information on the second subsystem: the base station.
Once I receive the challenge kit, I'll post my tinkering experience with the kits next week as well.
Pls do comment for suggestions and questions. Thank you.
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