Temperature Sensors

OneWire Temperature Sensors

Temperature Sensors mounted to the pulse jet

The purpose of having the temperature sensors is to see what areas of the pulse jet get hot and how hot are the gasses in the combustion chamber and at the exit of the pulse jet. To determine how hot the inside of the combustion chamber gets, knowledge of heat transfer is required. The kind of metal that makes the pulse jet is needed in order to derive the specific heat coefficient values to conduct heat transfer from the metal of the sensor to the metal of the pulse jet to the inside of the pulse jet.

Temperature Sensors Inputs & Outputs

The inputs for the Temperature Sensors are:

Temperature Sensor probe: Temperature

Red wire: 5 Volts

Black wire: GND

The corresponding outputs are:

Orange\Yellow Wire: One Wire Bus

More information on the One wire temperature can be using this link:

https://www.amazon.com/gp/product/B012C597T0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Picture of the Temperature Sensors Circuit A

Picture of the Temperature Sensors Circuit B

C++ Temperature Sensors Code

#include <OneWire.h>

#include <DallasTemperature.h>

// OneWire DS18S20, DS18B20, DS1822 Temperature Example

// http://www.pjrc.com/teensy/td_libs_OneWire.html

// The DallasTemperature library can do all this work for you!

// https://github.com/milesburton/Arduino-Temperature-Control-Library

OneWire oneWire(5); // on pin 10 (a 4.7K resistor is necessary)

DallasTemperature sensors(&oneWire);

void setup(void) {

Serial.begin(250000);

sensors.begin();

}

void loop(void) {

/////////////////////////////////////////////////

//////////////////////////// Time

Serial.print("Time = ");

Serial.print(millis());

Serial.print(" ms, ");

/////////////////////////////////////////////////

//////////////////////////// Temperature Sensors

float temp1, temp2, temp3;

temp1 = sensors.getTempCByIndex(0);

temp2 = sensors.getTempCByIndex(1);

temp3 = sensors.getTempCByIndex(2);

Serial.print(temp1);

Serial.print(", ");

Serial.print(temp2);

Serial.print(", ");

Serial.print(temp3);

Serial.println(", ");

}

Configurations & considerations

Temperature Sensors Mount Configuration:

The Temperature sensor was initially linearly mounted on the pulse jet. During a test, the plastic part of the temperature sensors melted on the pulse jet. After that, all the Temperature sensors were removed. If Temperature sensors are to be used again, they must be heavily wrapped in heat-resistant tape.

Each Temperature Sensor has its own unique address and must be implemented in the code before use.

Pitot Tube Design Considerations:

Mounting the Temperature sensors upside down is a huge headache. Defiantly Develop the circuit of the temperature sensor on a separate board that is nonconductive and make sure that everything is working properly, and that each sensor has enough voltage throughout the bus. One Bad temperature sensor can destroy the whole bus. If the plastic part of the temperature gets to hot and melts, then that could change the ID of the temperature sensor and could also ruin the whole buss.
Defiantly consider using a different set of temperature sensors that are both easy to wire or at least easy to code for.
Determining how hot the combustion chamber gets is a whole project on its own.

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