GPS Simulator

Work has started on a GPS simulator that will eventually become a NearSys kit. The simulator creates the GPS sentences that a near spacecraft will see on a typical mission. The ascent rate and burst altitude are all programmable. It's also possible to create a lose of satellite lock.

The GPS simulator will allow anyone with a programmable flight computer to test their flight code on the ground. It will also let anyone with an APRS tracker observe the behavior of their tracker without leaving the ground.

The simulation will reduce the risk of mission failure due to unforeseen behavior caused by high altitude GPS sentences. It also will let inidividuals run a test on their entire near spacecraft to observe that it will function as desired. Tests like this increase the number of successful near space missions.

Next up is the near space simulator, a totable thermal vacuum chamber called Near Space in a Can.

NearSpace Easy Flight Computer

I've started testing on a new near space flight computer, the NearSpace Easy. It operates with a BASIC Stamp 2pe and shares the GPS data stream in parallel with a Tiny Trak 3. The Easy digitizes up to eight channels of analog data with a resolution of 12 bits. In addition, there are six digital ports and three servo ports.

A male DB-9 on the PCB is the GPS port. It provides power over pin 4 to the GPS as soon as it's plugged in. The GPS receivers NearSys will start selling are designed to interface to this flight computer (and the NearSpace UltraLight).

Connected by a wrapped cable is the flight computer's control panel. The panel mounts to the airframe of the near spacecraft to allow you to program both the flight computer and the APRS tracker, without having to open up the airframe. Also on the control panel are three power switches for the flight computer, servos, and audio beacon. Four indicator LEDs signal when the flight computer and servos have power, when the Tiny Trak has a GPS lock, and when the Tiny Trak is transmitting a position report. Finally, there is a mission commit pin that prevents the flight computer from recording data on the ground.

The NearSpace Easy can record up to 30 kb of data. In addition, USB jump drive adapters are sold for the BASIC Stamp that allow the storage of even greater amounts of data.

Not shown is the antenna. An antenna kit is part of the NearSpace Easy. It's a 2m dipole on the end of an RG-174 coax.

The NearSpace Easy is literally a plug and play near space flight computer. You'll need to select you battery (use a rechargeable lithium) and battery plug, but otherwise, just plug in the antenna and GPS and you're ready for a near space mission.

GPS Recievers - Real and Simulated

NearSys is preparing to sell GPS reciever kits for use with its near space flight computers and BalloonSat Extreme. The GPS receiver is the UniTraQ GT-320 with high altitude firmware.

The kit will include mounting materials, project box, and DB-9 connector. The GPS is designed to draw power through its DB-9 connector, so plug it into a flight computer and it's ready to produce output, no extra batteries required.

NearSys is also testing a new version of its GPS simulator. This version 2.0 will become a kit and produces more GPS sentences than before. It's greater sentence output make it a better near space and rocket flight mimic. You'll download the program with your desired flight parameters set and plug it into the flight computer. It's two buttons allow you to control when the GPS has a lock (or loses a lock) and when the balloon launch begins. The LEDs indicate power, status of GPS lock, and ascent/descent. Mission elapsed time (MET) and altitude are optionally displayed on a PC or laptop running the PICAXE program editor.

NearSys Flight 10G

The seventh flight of the year was launched Halooween morning form the Univeristy of Kansas. The mission as a practice for future KU flights next semester for the AE360 class, Introduction to Astronautics. The near spacecraft reaches an altitude of 98,500 feet according to the last GPS position report. Looking over the video, the near spacecraft made another 1,000 feet before the balloon burst, so it was closer to 99,000 feet. The flight was uneventful, until landing. The near spacecraft recovered in a tree too high for us to climb. It took three hours to get everything back. Next time, I'm bringing tree gear, like spikes and an expanding aluminum pole. Wings would be helpful, also.

Mission NearSys 10F

The sixth mission of 2010 for NearSys (and 83rd overall) took place 16 October 2010. Launch was from Indian Hills elementary school at 9:00 AM. Present were meteorology and physics students from Washburn University. The physics club designed the BalloonSat carried on this mission. The flight reached an altitude of 88,469 feet and was observed bursting from the ground at our stop in east Lawrence. I put together a short video that includes this film clip of the burst.

The Washburn BalloonSat carried a flight computer, weather station, and camera. Here's one of the photographs they recorded.

Napier's Bones Part 2

After seeing how students multiply multiple digit numbers by the lattice method, I was reminded of Napier’s Bones. John Napier (1550-1617) developed this tool for increasing the speed and accuracy of multiplications. His Napier’s Bones consisted of rectangular rods inside a board, or frame. On each rod, or bone, is written the multiplication of a single digit by 1, 2, 3, 4, 5, 6, 7, 8, and 9. Each number is written within a square divided by a diagonal line. Each tens digit is above the diagonal line and the ones digit is written below the diagonal line. The left side of the board is divided into squares marked with the digit 1 through 9. The squares on the side of the board are the same size as the squares on the bones. In fact, the fifth square on the left side of the board aligns with the fifth square in any bone. And that particular bone’s square has the value for five times the value of the bone. Since I have an interest in Baroque science, I decided to make my own set of bones.

This bone is for 9 and you can see it has written on it (starting from the top and working our way done) 9, 18, 27, 36, 45, 54, 63, 72, and 81. The best way to see how Napier ’s Bones are used is to work an example. So let’s multiply 25,806 by 79. You’ll need a sheet of paper and pencil to write the intermediate results.

First, load the bones for 25,806 into the board as shown below.

Now, we’ll first multiply 25,806 by 9 by reading off the sum of two digits in every diagonal formed by the numbers in the bones.

The product from multiplying 25,806 by 9 is read across the bones at the nine level of the board. Look on the left side of the board for the 9 and then start reading off numbers beginning on the right side and working your way to the left. First is the 4 all by itself in the lower right-hand corner. There is no other digit in its diagonal, so there is no other digit to add to 4, therefore just write a digit 4 on a sheet of paper.

Now move over to the next diagonal to the left, which contains 5 and 0 (0 is at its lower left of the 5). So add the 0 and the 5 to get 5. Write 5 to the left of the 4 you wrote first on the paper. You will have now written on your paper, 54

Now move over to the next diagonal to the left which contains the digits 0 and 2. Add these two digits together to get 2 and then write the digit 2 to the left of the 45 already written on the paper. You have 254 written on the paper now.

In the next diagonal as the digits 5 and 7. So add these two digits to get 12. Only write the 2 on the paper, the 1 (in the ten’s place) will be carried to the next diagonal. On your paper is now written 2254.

The next diagonal has the digits 4 and 8. Add those together and don’t forget to add the 1 carried from the previous diagonal. The result is 4 + 8 + 1, or 13. Again, only write the digit in the one’s place (a 2) on the paper (on the left side of the number you’ve written so far) and save the ten’s digit (a 1) so it can be carried to the next diagonal. The result on the paper so far is 32254.

The last diagonal is like the first diagonal in that there is only one digit. However, since the previous diagonal resulted in a carry, we’ll need to add that 1 to the 1 in this diagonal to get 2. Write 2 as the last digit on the paper. The result on the paper up to now is 232254. The number, 232,254 is the product of 25,805 X 9. Easy, wasn’t it?

In my next blog posting, we’ll add the product of 25,806 X 7. However, if you remember you multiplication, you know we’re going to write a 0 in the next line below the 232254 we’ve written so far and then add the digits for the product of 25,806 X 7.

Napier’s Bones Project

After seeing how students multiply multiple digit numbers by the lattice method, I was reminded of Napier’s Bones. John Napier (1550-1617) developed this tool for increasing the speed and accuracy of multiplications. His Napier’s Bones consisted of rectangular rods inside a board, or frame. On each rod, or bone, is written the multiplication of a single digit by 1, 2, 3, 4, 5, 6, 7, 8, and 9. Each number is written within a square divided by a diagonal line. Each tens digit is above the diagonal line and the ones digit is written below the diagonal line. The left side of the board is divided into squares marked with the digit 1 through 9. The squares on the side of the board are the same size as the squares on the bones. In fact, the fifth square on the left side of the board aligns with the fifth square in any bone. And that particular bone’s square has the value for five times the value of the bone. Since I have an interest in Baroque science, I decided to make my own set of bones.

Tomorrow I'll bring pictures and directions. Meanwhile, here is the link where I learned how to use them.

http://en.wikipedia.org/wiki/Napier's_bones

NearSys UltraLight Flight Computer

The first NearSys flight computer is now ready for purchase. The flight computer is programmed in BASIC and centered around the PICAXE-28X. The UltraLight has four analog channels, three digtal channels, two servo ports, and two camera ports. This means the UltraLight can record the analog values of four sensors, operate three digital devices including Geiger counters, control two servos, and operate two cameras. The flight computer has 32k of memory for storing mission data.

After building the UltraLight kit, you just ned to plug in a GPS receiver to be ready for flight. The flight computer contains a transmitter, TinyTrak based TNC, and a SMA antenna connector (the kit includes the cable and wire to make an antenna).

The UltraLight also includes a control panel that mounts to the near spacecraft airframe. The control panel permits the flight computer to be programmed without opening the airframe. The control panel has three power switches for main power, servo power, and audio beacon. The third switch powers up the audio beacon. the 90n dB piezo buzzer helps recovery crews locate the near spacecraft when it lands in tall grass of trees. Using a seperate battery pack for the servos insures that a bad servo can't ruin the science mission. The control panel also includes a Commit Pin that allows you to power up the near spacecraft long before launch without wasting memory recording data on the ground.

Additional information will appear on the NearSys website shortly (Nearsys.com/catalog).

Astrophotogaphy with a Digital Camera

I've been using a FinePix S7000 to make astronomic images from Topeka. Most of my images are of Jupiter and its four major satellites for an astronomy/physics lab I'd like to write (I hope to create an activity book of astronomy with this and other lab exercises). Last night, after photographing Jupiter, I used my planetarium program to identify the satellites in the image. I found out that the planet Uranus was just above Jupiter and upon checking my image, i realize I recorded the planet.

The picture was five seconds long with a zoom of six power (optical zoom, not digital). I'll keep photographing the planets to monitor the motions between them and the fixed stars.

BalloonSat Extreme

NearSys introduces the BalloonSat Extreme. This is one of the largest BalloonSat flight computers. At its heart is the BASIC Stamp 2 (the BS2pe is recommended), so it is powerful and easy to program.

The flight computer has an eight-channel analog port with 12-bits of resolution for sensors like weather stations. There is a five-channel digital port with connections directly to the BS2 for sensors like Geiger counters. Unlike other BalloonSat flight computers, the BalloonSat Extreme has a GPS Port to allow your BalloonSat to monitor and record GPS reports (like altitude and time). The flight computer can operate three cameras. The cameras can ones with modified shutter buttons or be Canon cameras running the CHDK USB remote program. The flight computer can also control three servos. The servos have a seperate power supply to prevent a bad servo from draining the main power supply.

Part of the BalloonSat Extreme kit is its Control Panel, a seperate printed circuit board. The Control Panel allows you to power up the flight computer without opening the BalloonSat. Two LEDs indicate power is available for the flight computer and the servos. Finally, there is a Commit Pin that allows the BalloonSat to be powered up long before launch. When ready for lift-off, pull the Commit Pin and the flight computer will begin recording data.

The entire kit is only $48. Check it out and its directions and sample code at, http://nearsys.com/catalog/balloonsat/extreme.htm

I'v spent a couple of months perfecting a hovercraft-based robot. My initial goal was to develop a line of robots that behaved like satellites in a weightless environment. They would not move around on wheels (what good are wheels in space?) but navigate around on jets of air (safer than hot rocket exhaust). I discovered though, that air hockey tables can't generate sufficient air flow to lift the robot base. After another year and a half of thinking, I decided to use a hovercraft base in place of the air table. The design I came up with was made possible my resources on the Internet. The toy hovercraft described where just the thing to help me develop the NearSys HoverBot. Unlike traditional robots, the HoverBot accelerates when it drives. Most robots travel at a fixed speed that makes it easier to program navigation goals. The HoverBot roboticist must think about time, acceleration, velocity, and displacement when navigating. Here's an introductory video. You can learn more in my Servo magazine article and can soon purchase a kit from my website, NearSys.com/catalog.

The NearSys HoverBot

I'v spent a couple of months perfecting a hovercraft-based robot. My initial goal was to develop a line of robots that behaved like satellites in a weightless environment. They would not move around on wheels (what good are wheels in space?) but navigate around on jets of air (safer than hot rocket exhaust). I discovered though, that air hockey tables can't generate sufficient air flow to lift the robot base.

After another year and a half of thinking, I decided to use a hovercraft base in place of the air table. The design I came up with was made possible my resources on the Internet. The toy hovercraft described where just the thing to help me develop the NearSys HoverBot.

Unlike traditional robots, the HoverBot accelerates when it drives. Most robots travel at a fixed speed that makes it easier to program navigation goals. The HoverBot roboticist must think about time, acceleration, velocity, and displacement when navigating.

Here's an introductory video. You can learn more in my Servo magazine article and can soon purchase a kit from my website, NearSys.com/catalog.

Test of Geiger Counters

Last week I launched two geiger counters into near space. The mission was for KU aerospace engineering students and I got to send my experiments along in the tracking capsule.

The first geiger counter is the reliable Aware Electronics RM-60. I've flown this geiger counter dozens of times and really love it. It measures everything, alphas, betas, and gammas. Aware has a range of geiger counter products that you'll love. See them at http://www.aw-el.com/

The second geiger counter was built from a kit that's available from Electronics Goldmine. The tube is Russian built and does not include a mica window for alpha particles. Here's the webpage for this product. http://www.goldmine-elec-products.com/prodinfo.asp?number=c6979

The Russian tube is suppose to be pretty sensitive. In my tests, it detects more background radiation. However, I don't have a calibrated source that I can verify that it's actually detecting properly. I have s short video on a test that you can watch on my YouTube channel, www.youtube.com/nearsys.

Below is a chart I produced with data from NearSys-10A. Note how much more radiation the Goldmine geiger counter is detecting.

Normally the RM-60 shows a drop off at 62,000 feet. The driop off doesn't happen until closer to 70,000 feet and it doesn't show up well at all for the Goldmine detector.

So much more to learn!

HoverBot

I finally got the Hoverbot set up with a relay H-Bridge. Unfortunately, one of the relays died. But that still gives me enough to demonstrate this proof of concept.

As you can see, the Hoverbot picks up quite a bit of speed when the drive fans are operating. In this video clip, the fans are on for three seconds and off for one. I've since reduced the lift fan's voltage to 4.5V (from 6V) and reduced the drive fans' voltages to 4.5 volts.

There are two problems to addess. The first is that the Hoverbot has a tendency to steer to the left. Experiments indicate it is due to the counter-clockwise spin of the lift fan. I may have to double up lift fans in a future design.

The second problem is that once the Hoverbot gets into a wobble, it won't come out. In fact, the drive fans are no longer effective in wobble. The HoverBot is going to have to detect this and correct it. Either an extendable foot or being able to shut down the lift fan is going to be required.

Enjoy the video

Clearing Misconceptions About Near Space Missions

I was thinking about these topics earlier this week and thought they ought to be cleared up. So if you'll permit me.

Most people are familiar with the concept that motion is relative. This means that motion to one person looks just the opposite to another person who is not sharing that motion. It's all a matter of your frame of reference.

When we discuss things like the ascent rates and maximum altitudes of a balloon, we really should be discussing these issues in their more accurate frame of reference, that of the balloon. In reality, the balloon is holding still and the earth (along with the atmosphere which is firmly attached to the earth via gravity) is falling. Apparently this occurs because when we put helium into a balloon, we're removing it from the earth and its atmosphere (I'll refer to these as the earth-atmosphere system). When you remove low density material from the earth-atmosphere, you're increasing its average density. Recall that dense objects sink and less dense objects can float. The denser earth-atmosphere now wants to sink. And as long as the filled balloon is firmly attached to the earth's surface (via gravity), like by a person holding the balloon's load line or by tying the load line to a helium bottle, the balloon will hold up the earth. So those of you who are holding the filled balloon before launch, you're really holding the earth-atmosphere up. Think about that next time.

Once the balloon is no longer tied to the earth, the earth-atmosphere falls away. As the earth and its atmosphere fall away, the balloon is surrounded by less and less dense air. The balloon expands as a result. Since the helium is trapped inside the balloon, there are no further changes in the earth-atmosphere's density and it falls away at a constant rate that is dictated by the friction of the air around the balloon. The atmosphere, which remember is firmly attached to the earth, can only slide pass the balloon at a limited rate. Friction is why the earth does not fall away from the balloon infinitely fast. Many of you have no doubt noticed that at some where around 30-40,000 feet, the balloon appears (and let me stress appears) to rise faster. This is the result of the earth-atmosphere slipping around the balloon faster because of changes in air density and balloon size. This is pretty obvious if you recall that the force of friction is based on factors like surface area and density.

At the point where the atmospheric pressure around the balloon is low enough, the balloon bursts and releases its helium back into the atmosphere. This mixing of helium back into the earth-atmosphere system decreases its average density and let's the earth and atmosphere float back up to the balloon. The air rising around the balloon payload makes it tumble (due to turbulence) and inflates the parachute. The mixing of the balloon's helium with the atmosphere occurs very rapidly and therefore, the change in the density of the earth-atmosphere is very fast. This makes the earth-atmosphere begin to rise very quickly. At the earth-atmosphere rises back up to the balloon, the air becomes denser and the parachute creates more drag, slowing the ascent of the earth-atmosphere. Therefore, we see the initial ascent of the earth-atmosphere is very fast at the start, but over time, the ascent rate slows down until the balloon and earth make contact. At that point, the earth-atmosphere system and balloon are back in equilibrium and the motion comes to an end.

Now, since the days of the Greeks, we've known the world is round or spherical. There is no friction between the earth-atmosphere system and outer space. So when you go on a balloon chase, your car tires are pushing the earth and making it rotate the opposite direction. Let me stress, your car is NOT MOVING!! Therefore, it would help if everyone in their cars would travel together and go the same direction. If your chase teams will push the earth in the same direction, you'll rotate the earth in the same direction more quickly and get the earth rotated into the proper alignment with the balloon more efficiently. Therefore, it is imperative that we prevent chase crews from leaving their homes from the opposite direction, as this pushes the earth in another direction at the same time. When one big and heavy chase truck tries to push the earth to the west, the rest of our lighter cars trying to push the earth to the east suffer. I for one do not want to see my gas mileage decrease because of this. So please be polite to everyone else and follow along with the rest of the pack.

This also highlights the importance of using the balloon launch announcements system. There are some weekends with multiple balloon launches. If they are occurring at the same time, our cars are fighting each other to rotate the earth to our proper positions. So be considerate and coordinate your launches with other teams across the country.

Just doing my part to clear things up,
Paul

(Next time I'll explain the relativistic effects of a balloon launch and why the Twin Paradox makes use younger after each balloon flight)

H-Bridge Problem

My HoverBot is grounded. The ducted fans that drive it require nearly 2A, but the TA78080K H-Bridges I'm using have built-in overload protection at 1A. I'd like to use H-Bridges so I can run the fans forwards and backwards. The TA8080's are lightweight and simple to use, so I really like them.

For an interim solution, I'll try using small relays. This won't give the Hoverbot turning ability, but at least it will test the concept until I can replace the H-Bridges.

Unit of the Einstein

After watching Avatar, I started thinking about the ship (the Venture Star) and how it got to Alpha Centauri. The ship is suppose to use a matter-antimatter drive that is sub-light in speed. The crew was suspended for the six year flight. Assuming a constant speed (this means the acceleration to speed was pretty fast), it had to travel at 0.7 the speed of light (0.7c).

The relativistic effects of this a speed is calculated with the equation, sq-rt[1-(v/c)^2]. Plugging in the values I get,
sq-rt[1-(.7/1)^2]
sq-rt[1-0.7^2]
sq-rt[1-0.49]
sq-rt[.51]
0.71

This means
Time passed 71% as fast for the crew
The Venture Star contracted to 71% of its length (it acually gets little more complicated)
Mass of the Venture Star and crew increased by 1.4 times (1/0.71) at speed.

I propose we give the number 0.71 the unit of the Einstein. So the ship traveled at a speed of 0.7c and the crew experienced a relativistic effect of 0.71 E.

At the speed of light, photons experience 0.0E while we traveling at nearly no speed experience 1.0 Einsteins of relativistic effect.

Perhaps Es could be integrated to account for the time the ship spent accelerating to speed. If so, the crew experienced less than 0.71 E of integrated relativisitic effects (would the unit be labled Ei?). Their maximum would still be 0.71 E.

What do you think?

Small GM Tube

I ordered the small glass GM tube from Electronics Goldmine (along with 2,000 T1 green LEDs that I will split with a sudent). A small tube like this can be powered by a transformer and 555 timer.

However, I wonder if there's a best frequency for the transformer and tube. Rather that adjust a pot on a 555, I'll use a PICAXE-08M to make the square ware. That gives the circuit a greater range of frequencies. Also, having some intelligence in the circuit will permit the tube to be shut down upon detection of a cosmic ray. Perhaps that will decrease its dead time. If that's not possible, then the PICAXE can produce a single pulse at detection and ignore the other pulses until after the tube's dead time. That will ensure a flight computer (which will monitor only the PICAXE and not the GM tube) will see a single pulse per detection (rather than the 5 or 6 it sees with the kit I've been testing).

Electronic Goldmine Geiger Counter

I added enough hot glue to the terminals of the GM tube to put an end to the corona discharge. I also ran a test of the Aware Electronics RM-60 beside the Electronics Goldmine Geiger counter. The Goldmine detector picked up six times as much radiation.

Here's what the current detector looks like.

Electronic Goldmine Geiger Counter Kit

As Mike Manes of EOSS suggested, I ran the geiger counter in a vacuum to make sure it didn't arc over. The tube has 600 volts across it, so this is an issue in low air pressure conditions. At first it looked fine. Then at 28 inches of mercury vacuum (about 94% vacuum), the LED indicator remained on. Some where the 600 volts was finding a ground and triggering the LED. I started coating the circuit in hot glue and have it running at lower pressures, but stil not in a full vacuum. I ran out of hot glue to do any more work, so I'll work again in this tomorrow.

Geiger Counter kit for Near Space

I've started my experiments with the Electronics Goldmine geiger counter kit (C6979). The kit was on special for $70 (down by $10). It operates from a nine volt battery and uses a 555 timer and transformer to boost the voltage to 600 volts. The 555 timer operates at 128 Hz. So when there's a detection of a cosmic ray, there are six (some times five) pulses during the GM tube's dead time.

Gas molecules inside a GM tube become ionized at the passage of a subatomic particle. The ionized gas lets electrons, pushed by the high voltage on the tube, pass from the wall of the GM tube to the center conductor. This makes the GM tube act like a switch at the passage of a cosmic ray. While the tube remains ionized, it's unable to detect other radiation events. How quickly the GM tube clears out this ionization is called the tube's dead time. The shorter the dead time, the more frequently the tube can detect radiation. In near space, I have detected up to 800 counts per minute. On average then, there is 75 milliseconds between detections. As long as the GM tube's dead time is less than that, it should accurately detect radiation levels in near space.

I'd like to try placing a capacitor across the GM tube to smooth out the voltage spikes. If that works, then the flight computer doesn't have to divide the number of counts by six to get the real radiation levels. Perhaps it will also let the tube clear out faster (reducing its dead time).

It's a short video about my experiments to date. Look for an article in Nuts and Volts this year.

Onwards and Upwards,

Your Near Space Guide

HoverBot Video

I've continued my experiments with designing small hovercraft. The video is short, but it shows I'm about ready to add a robot controller to a hovercraft. Balance is going to be a big issue. The lift fan is going to need lithium batteries, since they draw so much current.

Here's the YouTube link
http://www.youtube.com/watch?v=_ju40nRB_eE

Hover-Bot

I'm working on the base of a Hover-Bot. It's in the design stages, so only the lift factor has been checked. I have two more ducted fans on order and they'll supply the propulsive force for the Hover-Bot. My goal is to create a two dimensional simulation of satellites.

In traditional robots, when the motors are shut off, the robot stops. Not so for a "nearly" frictionless sliding robot. To get the Hover-Bot to stop, it must apply reverse thrust to counteract the initial thrust that got it moving. There's also the issue of sliding sideways.

Currently I'm investigating the amount of current the lift fan draws based on the supply voltage.

I have a movie clip that I'll post shortly.

CheapBot Single Axis Arm

Here's the demonstration of the new single axis robotic arm I developed. It's a simple deign that's suitable for entry level robotics competitions. In this case, the CheapBot robot is combining a line follower, beacon detector, and robotic arm to carry plastic balls from a pick up point (which is marked by an IR beacon) and carries them to a destination. Both the pick up point and the destination are marked with black tape. A robot in a game like this would score points based on the number of balls it delievered in a fixed period of time. In the case of a tie, the smaller progam (in bytes) wins.

I'm developing a simple robotic arm for 4H competition. The arm is single axis (it rasies and lowers) and is capable of carrying and dropping a lightweight plastic ball. Currently, this robotics testbed seeks the black line at the end of the game arena and raises its arm. To tell you it's ready for a ball, it beeps - and gives you three seconds to load it. Afterwards, it turns and drives for a few seconds before lowering the arm and dropping off the ball.

The next update will have the robot drive back and forth between two black lines, picking up and delievering balls. Instead of waiting three seconds for you to load a ball, I'll add a switch to the arm so the robot can tell when one has been loaded.

I'm still trying to prefect my IR beacon. I want the robot to determine which end of the arena is the pick up point because of the beacon above it.

US Geek Shortage

Here's an interesting article.

www.wired.com/dangerroom/2010/01/darpa-us-geek-shortage-is-a-national-security-risk/

We need to be teaching and encouraging more kids to take science,math,and engineering classes. Is there a US FIRST club at your local high school? They could always use some help.