Team:NCKU Tainan/Demonstrate


Sensing Boat

We build a nitrate sensing boat, consisting of motor and control modules, pH meter, thermometer and the most important nitrate sensor to make it more user-friendly.

Our sensing boat can detect exact water data immediately and prevent fish farmers from wasting a lot of time and efforts to collect water samples and deliver to professional institutes for examination.

Procedure of Sensing Boat

  1. Turn on the power.
  2. Place it into the pond or somewhere you want to collect data and use control module to control the boat.
  3. Receive the result, that is nitrate concentration, water temperature and pH value, through our App. We also have GPS on our boat so that users can track the path of sensing boat via smart devices.

Functions of Each Part of The Boat

We use Arduino as our MCU. Our boat can achieve several different functions which includes nitrate sensor, pH meter, thermometer and GPS. Besides, the communication interface of our boat and remoter is 2.4G radio.

Electrical Parts

Figure 1. Components of our sensing boat.

Figure 2. Nitrate sensor
SP-1KL anode connects to yellow wire.
SP-1KL negative connects to green wire.

These two wires connect to 10M ohm pull-up resistor on circuit board and then circuit board connects to Arduino pin1 and ground.

Figure 3. pH Meter

Figure 4. Thermometer

We receive GPS signal with Linkit. Linkit is a MCU which is equipped with WiFi and GPS module.

2.4 GHz radio module:
2.4GHz is the free bandwidth for research or homemade devices. We bought a pair of NRF24L01+PA+LNA which can transmit signal as far as 1 kilometer in open space. Pretty amazing doesn’t it? To transmit data with this module, we use RF24 library to control the module.

Figure 5. The pin 5, 6, 7 are for SPI interface and they are pin 13, 11, 12 respectively.

The code of transmitting side

        RF24 radio(6, 5);
        const byte address[6] = "00001";
        void setup() {

        void loop() {
          const char SendingContent[] = "iGEM NCKU";
          radio.write(&SendingContent, sizeof(SendingContent));

The code of receiving side

     RF24 radio(6, 5); // CE, CSN
     const byte address[6] = "00001";

     void setup() {
     radio.openReadingPipe(0, address);

     void loop() {
        if (radio.available()) {
	   char ReceivingContent[32] = "";, sizeof(ReceivingContent));


Mechanical & Physical Parts

Figure 6. Solenoid Valve

Figure 7. Motor

We use 775 motor whose rated voltage is 12V and initial current is 10A. The speed of this motor is 7000 to 20000 rpm.

Figure 8. Servo motor

The servo motor we use is MG996R whose torque is 13.5kgcm and range is from 0 to 180. And the gears inside are metal ones which allow it heavier loading.

Structure of Sensing Boat

This is NO PROBLEM. Robust, extremely accurate, remote controlled sensing system. Users can use it to gather data immediately and automatically every day without wasting a lot of time. Nitrate sensor is a device with reactor and laser. The reactor contains genetically modified E. coli and will emit different fluorescence intensity when dealing with various concentration of nitrate in water. By determining the fluorescence intensity and cross-referring with data lines which we've built in advance, we can accurately calculate the concentration of nitrate in water. Additionally, pH meter and thermometer allow us to obtain basic info of water. After determining those characteristics of water and combing with GPS data, we will upload them on to server and transfer those data to our App. By using smartphone, the users can easily get the information about their fish pond. At last, they can make the appropriate solution before it is too late to regulate the water quality.

Regulation Box

Nitrate, is one of the most important nutrition for aquatics, but too much nitrate will cause eutrophication. So, we build a regulation box if our sensing boat reports us a high nitrate concentration level. When facing this problem, fish farmers would change water frequently to keep nitrate concentration low enough for aquatics to live. However, they can prevent this situation easily by using our regulation box.

Procedure of Regulation Box

  1. Turn on motor power and UV light power.
  2. When nitrate concentration is too high, our App will show warning for users and users can push the bottom from App to let regulation box to work.

Regulation Box Components


Structure of Regulation Box

To achieve our goal, the regulation box needs to consist of some elements, that is water input hole, output hole, “motor and filter system” and replaceable grooves. When regulation box starts to work, it pumps water into the box by motor system. At the same time, water flows through filter system for physical water purifying and then goes into our main part, replaceable grooves, to do biological transformation. We use our manipulated E. coli, with genes for NiR, GS and GDH constructed, and take MG1655 wild type as our pioneer. Because of the ability to transform nitrate to nitrite, to open the pathway. NiR is a kind of nitrite reductase and can make nitrate become ammonia. Furthermore, ammonia is taken as a reactant to form glutamate, an essential amino acid for creatures, by GDH. Due to GS catalyzing, glutamate become glutamine, a common seen and expensive content in health supplements. At last, clean water appears and the whole aqua system can stay healthy. Moreover, this pathway isn’t new at all. On account of this, the feasibility is a hundred percent.


It's also proved to be functional and efficient with our functional test.

In the test of device, first of all, we added nitrite to the tank. Then, we monitoring nitrite concentration at 2, 4, 8, 12 hours separately. Apparently, we can see that the device with our manipulated E.coli can sharply decrease nitrite in the water.
For biosafety, we keep our regulation box running isolated and equip the box with biological filter which makes our device prevent from bacteria leaked and pollution. Also, we add UV light at the top of regulation box to make sure our safety condition stay secure.