Systems
About Systems II
The systems for Raider II were very similar to Raider I with the following exceptions and changes:
Additional Sensors (Geiger Counter, Ozone Sensor, extra UV sensor, APRS transmitter)
Programming for the UV sensor outputs UV-A/UV-B and UV index
Construction Process
We started this new iteration of the systems for Project Horizon by talking with the science team to discuss what experiments we would be accomplishing this year.
This year we were trying to incorporate new sensors such as Geiger counters, Ozone sensor, and UV sensors. We got a lot of help from our local electrical engineer Stefan Gross and our mentor Nathaniel Schaff who both helped in the assembly and coding of the systems.
Complications
Topics to expand on here:
Original Systems head leaving
Covid-19
Broken Ozone Sensor
Broken Geiger Counter
What We Learned
The Moore Airborne Modular Data Acquisition Unit (MAMDAU) II.0
Added Sensors
The Ozone Sensor
Background
Electrochemical ozone sensors such as the ones we are using are a relatively new technology. Being cheaper than conventional ozone sensors and much more reliable, electrochemical ozone sensors have grown rapidly in industrial applications.
Functionality
The DGS-O3 Ozone sensor is a module that records the current concentration of Ozone (O3) in a given area.
Processes
The ozone sensor itself determines the concentration of ozone through an electrochemical process.
This component on the left shown is integrated within the ozone sensor. Shown is a porous membrane allowing certain gases such as ozone to diffuse and interact with smaller components. Within the porous membrane there are electrolytes and electrodes, when an ozone molecule hits a electrolyte there is a change in the electrochemical potential between the electrodes allowing electrons to flow, thus completing a circuit.
An electrochemical potential is the tendency of a molecule to gravitate to an electromagnetic source to reduce its potential energy. An example is a cup of Na+ ions in water. If there is an electromagnetic source, the Na+ ions will concentrate towards the source in order to reduce its potential energy. Molecules always tend to gravitate towards a place with lower electrochemical potential. This process is seen used within the ozone sensor, within the porous membrane there is a lower electrochemical potential which attracts O3 molecules. In summation, ozone molecules are attracted to the center of the porous and concentrate themselves there.
Shown is the ozone molecule. Since an ozone molecule is polar, through vector addition of it’s charges and trigonal planar shape, it is attracted to an area with lower electrochemical potential.
Once the O3 is concentrated within the porous membrane electrons can safely flow between two points allowing for readings to be taken. The definition of an electrode is an item that has a low electrochemical potential to attract molecules. The electrons that pass through are able to be recorded and interpreted as ozone concentration.
Outputs
Once the sensor is started up, it will self calibrate. A very large magnitude will be shown initially and will level off to the appropriate ozone concentration.
The output of the ozone concentration is in parts per million (PPM). Out of every million molecules in the air, X amount occurs in volume. These are also the units produced.
Feasible Experiments
Concentration of ozone throughout the atmospheric layers
Effect of ozone on temperature sensors
Effect of ozone on radiation (Geiger counter)
Effects of ozone on different types of rubber (ozone attacks the double bonds in rubber deteriorating it, some types are more sensitive than others)
Limits
Resolution of up to a concentration of 20 parts per million
Humidity affects readings immensely
Very sensitive to electromagnetic interference
Works in temperatures -20 C to 40 C (-30 C to 55C for short periods of time)
The Geiger Counter
Background
The SBM-20 radiation tube (СБМ-20 in Cyrillic) is an old radiation detector of Soviet design. It was mass produced and used industrially from 1970 - 1990. Although old, these radiation detector tubes still work very well and are often used by hobbyists.
We are using the Mighty Ohm Geiger Counter for Raider II
Functionality
The SBM-20 radiation detector is a module that records Beta and Gamma radiation in its surroundings. It is meant to measure low level radiation.
Processes
The SBM-20 tube utilizes the Geiger-Müller method in measuring the surrounding radiation.
A tube with a very thin wall is created and in the very center contains the positive anode. On both sides of the tube contains the negative cathodes. The tube is sealed and within there is a mixture of inert noble gas and halogen vapor, these gases are kept at a very low pressure. When ionized radiation hits a halogen atom (beta or gamma radiation) energy is released allowing electrons to be carried through the tube and generate a signal.
Shown above is an electron in an atom. When ionization energy hits an atom it excites the electron to another orbital level. The electron in these excited states has a tendency to return to its original level or ground state. When the electron returns to this ground state energy is released, creating an avalanche of energy travelling along the radiation tube. This wave of energy conducts electrons and allows for a spike or tick from the sensor.
By detecting the amount of spikes from these ionized radiations hitting the atoms, pulses can be shown generating a set of ticks. The amount of ticks in a time frame indicate the ionization energy in the general surroundings.
Outputs
The data measured by the Geiger counter is in counts per minute (CPM) and millirads. Rads are the amount of joules absorbed by 1 gram of matter. The SBM-20 has a working range of 0.004 to 40 millirads per second. In comparison, background radiation is usually around 0.001 to 0.004 millirads per second.
Shown is an output of the SBM-20 tube in CPM. The average number of ticks in a minute is averaged out and is put out as a number, shown on the right.
Feasible Experiments
Effect of radiation on temperature sensors
Effect of radiation on cameras
Effects of radiation on rubber (rubber vulcanizes decreasing tensile strength immensely)
Radiation in different levels of the atmosphere
Limits
-60C - 70C temperature range
Voltage of 350 - 475 DC recommended 400 V
Dead time of 190 microseconds
List of old parts used in Raider II
Eagle Flight Computer
Description: This is the Eagle flight computer that comes with the high altitude balloon. It is equipped with a GPS receiver for tracking its flight and a pressure sensor.
Data collection: GPS Location (Not a tracker), pressure sensor
Power Usage: Uses 3 AA batteries. These will last for up to 15 hours
Price: $300
MAMDAU Flight Computer
Description: This is the flight computer which was capable of collecting all of the information from the various sensors on the Raider I.
2x Raspberry Pi Zero: We used a Raspberry Pi Zero due to its small form factor.
Price:
Raspberry Pi Zero: ~$10 (Depends on where you buy it)
2x UV Sensor
Description: This UV Sensor would detect, as it sounds in the name, UV Radiation levels as we head up. This data would show us, in combination with the pressure and spot tracker, where and when the UV Radiation is strongest, and at what altitudes.
Data Collection: UV-B, UV-A, UV-Index
Operating Voltages: 1.7V-3.6V
Price: $7
Raspberry Pi Zero Camera V1.3 Mini (Marshmallow Shot)
Description: This is a small camera that attaches to a Raspberry Pi zero via a ribbon cable.
Data Collection: Took pictures in '.jpg'
Sensor: 5 megapixel OV5647 sensor
Price: $20
Double-A Battery Pack
Description: A battery pack that would supply the power to all of the sensors and modules on Raider I.
Price: $7
Trackers used in RAIDER II
GPS: In the first Raider flight, the purpose of the GPS is to locate the payload in altitudes in between 0-10,000 feet. The GPS synergizes with the Spot Tracker to give us complete altitude coverage.
GPS used: TK102B
Bandwidth: 850 / 900 / 1800 / 1900MHz
Working voltage: DC 9 – 58V
Radio Service: TCP/IP
Working temperature: -20℃ - 55℃
Spot Tracker: The Spot Tracker is used for high altitude tracking and was utilized during Raider I. The one flaw it has is when the Tracker flips upside down, the Spot Tracker does not work.
Device Model: Spot Trace
Bandwidth: 1611.25 Mhz - 1618.75 Mhz (4 Channels)
Working Voltage: AAA Energizer (3x)
Radio Service: TCP/IP
Working Temperature: -33 C to 60 C
APRS:
Bandwidth:
Radio Service:
Working Temperature:
Cameras used in Raider II (not including pi camera)
2x Ape-Man (Ground and Up shot)
Description: We had two Ape-Mans. One was facing downwards towards the Earth as we sent it up, and the other had faced upwards toward the sky, along with being aimed at the weather balloon. And our big goal with the upwards facing camera was to capture the weather balloon popping.
Model: Apeman A80 4K Actioncam
Camera Resolution: "4K" (Actually 1080p)
Power Usage: 3.7v (90 Minutes on a full charge)
Price: ~$50
Go-Pro (Horizon Shot)
Description: This was our first horizon shot, it was the shot that captured what we call the “money shot”, which was a wood cut-out of our school’s logo that was put on the horizon.
Model: GoPro Hero 7 Black
Camera Resolution: 4K 30FPS
Power Usage: 4.40v (~2 Hours on a single charge)
Price: $250
Cannon PowerShot SX620 HS
Description: This was our second horizon shot, it was supposed to be the shot that captured the scenery outward into the distance, but instead either died or got exposed to too much radiation on the way up as it lost our footage.
Model: PowerShot SX620 HS
Camera Resolution:
Power Usage:
Price:
REsults and what we learned
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