MS-2000

LEARN THE SCIENCE

Everything inside the MS-2000 is real science. Here is how each part works, words to know, and something to try.

Good for the board, for judges' questions, and for the build.

1

Mosquitoes

The tiny bug that is the deadliest animal on Earth.

There are more than 3,500 kinds of mosquitoes. Only the females bite. They need the protein in blood to make their eggs. Males drink flower nectar.

Mosquitoes find people by smelling the carbon dioxide we breathe out, then following our body heat and skin smell.

Some mosquitoes carry germs that cause malaria, dengue, and Zika. Malaria alone kills about 600,000 people a year, most of them young children. That is why scientists keep inventing new ways to stop mosquitoes.

Species: One kind of living thing.
Disease: An illness. Some are spread by germs that ride inside mosquitoes.
Try it
The buzz you hear is a mosquito’s wings beating about 500 times every second. Count how many times you can flap your arms in one second.
Did you know?
A mosquito flies about 1 mile per hour. You walk about 3 times faster.
2

Light and lasers

A laser makes light that is one color and stays in a narrow beam.

A flashlight sprays light in every direction and in many colors mixed together. A laser makes light that is all one color and all goes the same way, so the beam stays thin even far away.

Our laser is red, with a wavelength of 650 nanometers. Laser power is measured in watts. Our laser is less than 1 milliwatt, which is less than one thousandth of a watt.

Lasers are sorted into safety classes. Class 2 lasers are visible and under 1 milliwatt. If one flashes in your eye by accident, you blink in about a quarter of a second, and that protects you. You should still never look into any laser.

MS-2000 laser0.001 W
Class 3R limit0.005 W
Enough to kill a mosquito14 W

Each step along the bar is 10 times more power.

Laser: Stands for Light Amplification by Stimulated Emission of Radiation.
Watt: A unit that measures power. A small night light uses about 1 watt.
Milliwatt: One thousandth of a watt.
Try it
In a dark room, shine a flashlight at a wall from across the room. Look how wide the spot gets. A laser dot would stay about as small as a pea.
Did you know?
The first laser was built in 1960. Now lasers are in barcode scanners, printers, and car headlights.
3

The real laser fence

Scientists already built a machine that shoots mosquitoes with lasers.

Engineers at a lab called Intellectual Ventures built the Photonic Fence. Cameras watch the air, a computer finds each flying bug, and a laser zaps the mosquitoes. It can even tell a mosquito from a bee by how fast its wings beat.

In 2020, scientists measured how much laser light it takes to kill a mosquito. Using their numbers, a laser would need about 14 watts to kill one in a quick 25 millisecond flash.

The MS-2000 uses 0.001 watts. 14 divided by 0.001 is 14,000. So our laser is about 14,000 times too weak to hurt a mosquito. That is on purpose. Instead of killing it, the MS-2000 proves it could hit it, every time.

Prototype: A first working model of an invention, used to test the idea.
Lethal: Strong enough to kill.
Try it
Multiply it out: if 1 milliwatt were 1 step, how many steps would 14 watts be? (Answer: 14,000 steps. That is about 5 miles of kid steps.)
Did you know?
A 14 watt laser is Class 4, the most dangerous class. Science fairs do not allow them.
4

How a camera learns

The HuskyLens learns what the mosquito looks like from examples.

A camera picture is made of tiny colored dots called pixels. The HuskyLens sees a picture 320 pixels wide and 240 pixels tall, many times every second.

When you press its learn button, it studies the mosquito from lots of pictures. After that it can find the mosquito in new pictures and draw a box around it. Learning from examples instead of being told exact rules is called machine learning.

The HuskyLens tells the micro:bit where the middle of the box is. The middle of the whole screen is at 160 across and 120 down. If the mosquito is at 200 across, it is 40 pixels to the right of center.

center 160, 120mosquito 200, 10440 right, 16 up320 pixels wide × 240 tall
Pixel: One tiny dot in a digital picture.
Machine learning: A computer learning a pattern from examples.
Coordinates: Two numbers that say where something is: across, then down.
Try it
Teach the HuskyLens a toy. Then show it a different toy. Does it get fooled? Teach it from more sides and try again.
Did you know?
The camera works best with good light and a plain background. That is why the MS-2000 uses a black backdrop.
5

Aiming with servos

Two servos point the head: one turns left and right, one tilts up and down.

A servo is a small motor that turns to an exact angle, from 0 to 180 degrees, and holds it there. Turning left and right is called pan. Turning up and down is called tilt.

The micro:bit aims with a feedback loop. It looks where the mosquito is, turns a little toward it, looks again, and turns again, many times a second. The farther off center the mosquito is, the bigger the turn. When it is close to the middle, the turret fires.

Our servos have a clutch inside. If someone grabs the turret, the clutch slips instead of breaking the gears.

Degree: A unit for measuring turns. A full circle is 360 degrees.
Feedback loop: Check, adjust, check again, over and over.
Pan and tilt: Left and right, and up and down.
Try it
Close your eyes, have someone hold up a toy, open your eyes and point at it. You just did a feedback loop: look, move, check.
Did you know?
Security cameras, telescopes, and movie cameras all use pan and tilt heads.
6

The brains: micro:bit and code

Code is a list of steps a computer follows exactly, in order.

The MS-2000 has two micro:bits. The turret one reads the camera, moves the servos, and fires the laser. The wand one feels hits, flashes the eyes, and saves the data. They talk to each other by radio.

The code uses three big ideas. A loop repeats steps forever. An if checks something and decides what to do. A variable is a box that remembers a number, like how many hits so far.

The laser is switched by a relay. A relay is a switch flipped by a small electromagnet. Listen for the click when it fires.

forever
  if camera sees the mosquito
    turn pan toward it a little
    turn tilt toward it a little
    if it is near the center
      fire the laser, play pew
    else
      laser off
Loop: Steps that repeat.
If / then: A decision: if this is true, then do that.
Variable: A named box that holds a number.
Try it
Write the turret steps on paper as if/then sentences, like "if the mosquito is right of center, then turn right."
Did you know?
The micro:bit radio can reach about 20 meters, farther than the whole science fair table.
7

Proving a hit

A light sensor inside the mosquito turns light into a number.

The light sensor lets more electricity through when more light shines on it. The micro:bit reads that as a number from 0, fully dark, up to 1023, very bright.

The front of the mosquito pod is thin white plastic. When the laser dot lands on it, the whole cup glows, and the sensor inside sees the number jump. The code picks a threshold: a number higher than the room light but lower than a laser hit. Above the threshold means HIT.

On a hit, two red LEDs flash as the mosquito’s eyes. Each LED has a 220 ohm resistor so too much electricity cannot burn it out.

Sensor: A part that notices something, like light, and turns it into a signal.
Threshold: The line between yes and no.
Circuit: A complete loop that electricity flows around.
Resistor: A part that slows down electricity.
Try it
With the wand code running, read the number in room light, with the lamp off, and with the laser on the pod. Write all three down. Pick your threshold.
Did you know?
Because the light level is saved on every run, the data can show if a bright room made hits harder to notice.
8

Sound effects

Sound is air shaking. Faster shaking makes a higher pitch.

A speaker has a paper or plastic cone that moves back and forth very fast. That pushes the air, and the air carries the shaking to your ears.

How many times it shakes each second is called frequency, measured in hertz. A low boom is slow shaking. A high beep is fast shaking. A laser pew is a high pitch that slides down quickly.

The MS-2000 plays a pew or a boom when it fires (you pick with a button), a beep when it locks on, a splat on the wand when it hits, and a victory song at the end.

Frequency: How many times something shakes each second.
Hertz: The unit for frequency. 1 hertz is one shake per second.
Pitch: How high or low a sound is.
Try it
In MakeCode, play a tone at 500 hertz. That is close to a mosquito buzz. Now try 100 and 2000.
Did you know?
People can hear from about 20 hertz up to about 20,000 hertz. Many grown-ups cannot hear the highest ones anymore.
9

The pendulum: making speed

The higher you pull it back, the faster it swings through the bottom.

To test a fast mosquito and a slow one, the mosquito hangs from a line and swings like a pendulum. Pulling it back to a higher angle gives it more energy, so it moves faster at the bottom of the swing.

The pivot has marks at 10, 20, and 30 degrees, so every run starts from exactly the same place. That makes the test fair.

Here is something neat: at these small angles, the time for one swing stays almost the same. Only the speed changes. Galileo discovered this more than 400 years ago.

Speed at the bottom of the swing
10°
slow
20°
2× faster
30°
3× faster

Twice the angle, about twice the speed. Three times, about three times.

Pendulum: A weight that swings back and forth from a fixed point.
Energy: What something needs to move or change.
Try it
Swing the mosquito from 10 degrees and from 30. Count swings in 10 seconds each time. Are the counts close?
Did you know?
Pendulums kept time in clocks for almost 300 years.
10

Running a fair test

Change one thing, measure what happens, and keep everything else the same.

The engineering goal is to build a robot that finds, tracks, and hits a flying mosquito by itself. The science question is what makes it miss more: a faster mosquito or a smaller one. There are two tests: speed (10, 20, 30 degrees) and target size (a black cover over the pod with a 40, 20, or 10 mm hole). Every run is 3 feet from the camera, because that is where the laser is lined up.

Each setting gets 5 runs, and each run lasts 30 seconds. 2 tests, 3 settings each, 5 runs each: 2 × 3 × 5 = 30 runs. The wand saves the test, setting, run number, hits, time to first hit, and room light level for every run. The test that drops the hits the most is the biggest reason the MS-2000 misses.

To find the average, add up the 5 runs and divide by 5. Then make one bar graph for each test, with one bar for each setting.

Example: hits in 5 runs at 10 degrees
4
5
3
4
4
4 + 5 + 3 + 4 + 4 = 20, and 20 ÷ 5 = 4 hits on average
Variable you change: What you change on purpose (swing angle or target size).
Variable you measure: What you count (hits, and time to first hit).
Controlled variables: Everything you keep the same (the 3 foot distance, room, a charged power bank, camera training).
Hypothesis: Your best guess before you test, and why.
Try it
Write your hypothesis now, before any runs: "I think a faster mosquito will get hit (more / less / the same) because..."
Did you know?
Every run counts, even the bad ones. Only redo a run if something broke, and write down what happened.
11

How engineers invent

Ask, imagine, plan, create, test, improve. Then do it again.

Engineers follow a loop called the engineering design process. The MS-2000 has used every step: asking how to stop mosquitoes, imagining an air cannon, a vacuum, and lasers, planning three designs and picking one, and now creating it.

Testing always finds problems. That is good. Each problem fixed makes the invention better. Keep notes and photos of what went wrong and how it got fixed; judges love that.

Requirement: Something the invention must do.
Trade-off: Giving up a little of one thing to get more of another.
Try it
Write down why you picked Design A over B and C. That goes on the board.
Did you know?
The first design is almost never the final one. The MS-2000 plan was rewritten six times before anything was printed.

All the words

Use these on the board and when the judges ask questions.

CircuitA complete loop that electricity flows around.
Controlled variablesEverything you keep the same (the 3 foot distance, room, a charged power bank, camera training).
CoordinatesTwo numbers that say where something is: across, then down.
DegreeA unit for measuring turns. A full circle is 360 degrees.
DiseaseAn illness. Some are spread by germs that ride inside mosquitoes.
EnergyWhat something needs to move or change.
Feedback loopCheck, adjust, check again, over and over.
FrequencyHow many times something shakes each second.
HertzThe unit for frequency. 1 hertz is one shake per second.
HypothesisYour best guess before you test, and why.
If / thenA decision: if this is true, then do that.
LaserStands for Light Amplification by Stimulated Emission of Radiation.
LethalStrong enough to kill.
LoopSteps that repeat.
Machine learningA computer learning a pattern from examples.
MilliwattOne thousandth of a watt.
Pan and tiltLeft and right, and up and down.
PendulumA weight that swings back and forth from a fixed point.
PitchHow high or low a sound is.
PixelOne tiny dot in a digital picture.
PrototypeA first working model of an invention, used to test the idea.
RequirementSomething the invention must do.
ResistorA part that slows down electricity.
SensorA part that notices something, like light, and turns it into a signal.
SpeciesOne kind of living thing.
ThresholdThe line between yes and no.
Trade-offGiving up a little of one thing to get more of another.
VariableA named box that holds a number.
Variable you changeWhat you change on purpose (swing angle or target size).
Variable you measureWhat you count (hits, and time to first hit).
WattA unit that measures power. A small night light uses about 1 watt.
Build itFair guideBuild your ownExperiment rules in the full plan