Monday, December 14, 2009
I saw a problem were the arm successfully picked up a jack, but then dropped it after rasing the arm. I'm going to need to add a line of code to the robot to check the switch at the end of the arm one more time after the arm is brought up. I only have three bytes of memory left, I hope I can shoehorn that in.
Sunday, December 13, 2009
You can see a lever switch attached to the nose of the arm. That's so the robot can detect that it has picked up an object
In the snare test video above, you can see the piano wire snare extend, the arm drop, the snare retract, and the arm raise with the toy jack.
Look for one or more arm kits (I'm working on a second design), a radio, and smart beacon kit early next year.
May all your holidays be robotic.
Wednesday, December 9, 2009
I just completed my CheapBot Squeak program for my Constructivist Philosophy class and will post the final program on my webpage (NearSys.com) under the catalog link this weekend. It's a work in progress and over the months, I hope to include programs that simulate more features of the CheapBot and even create simulations of a near space mission.
Monday, November 23, 2009
Tuesday, November 10, 2009
For my final project, I'm writing a simulator for the CheapBots. The simulator lets a person control the H-Bridges of the robot in order to drive it around. In other words, the user acts like the robot controller. Future abilities of the program will let users observe the responses of the CheapBot Line Follower as the robot drives around.
The software is free at www.squeakland.org
Saturday, October 31, 2009
This is my first attempt to limb sound from near space. These images were taken every 10,000 feet and stitched together. I tried to select the best, where the camera was pointed in the same direction. As you can see, they don't all line up properly, but it is a start.
In the future, I'll fly a sun sensor to let the flight computer align the camera properly. I also need to calibrate the field of view of the camera so the horizons can be properly aligned in the images (the horizon is depressed in near space - my photo montage assumes the horizon is not).
I'll put an article together for Nuts and Volts on this line of work. I assume it will be useful for detecting haze layers, including volcanic ash, in the future.
Wednesday, October 28, 2009
The radios opewrate at a frequency of 434 MHz. If I take that frequency and divide it into 486, I get the proper length of the antenna (which will be a dipole). That comes out to 1.078 feet, or 12.936 inches. Divided in half and I get each element should be 6.5" long.
You can find an antenna calculator at http://www.crompton.com/wa3dsp/hamradio/antcalc.html
Monday, October 26, 2009
The hand controller communicates with your robot like we communicate with rovers on Mars. Messages sent to the rover are acted upon, but intelligently, not as an automatic reponse like an RC car. That way, if you send a message to drive off a cliff, the robot can analyze your message and refuse to comply. Not only will it refuse, it will also send a message back about why it isn't complying.
Thursday, October 22, 2009
I want to try a thinner wire. To make it simple to use, the lasso must be really flexible to wrap around the target regardless of how sloppy the positioning between the arm and the target is. The wire lasso also keeps the end of the arm very light, an important issue when you have a six inch long arm (you can build up a lot of torque for the servo to lift).
Rubber stoppers take out some of the slop in holding the target. I need to find a lighter weight "cushion" for this purpose and an easy way to mount it. I'll look into a foam rubber shirt for the end of the arm as a replacement.
I'll post some pictures soon.
Tuesday, October 20, 2009
This one was taken shortly after balloon burst. From around 80,000 feet, we're looking at the cloud cover over Melvern(?) Lake.
We're getting closer.....
Monday, October 19, 2009
Since it was two flights, there are two webpages for the results.
The only bad thing to happen was nylon zip ties failing and dropping one of the trackers (it's battery was dead by then). So it looks like I'll start some testing of zip ties in cold temperatures to see what I can learn from the experience.
Sunday, October 18, 2009
However, after listening to the Balloon Boy story out of Fort Collins, I can't help but wonder if this is going to impact amateur near space exploration. All it takes is for one irresponsible person to negatively change public perceptions of amateur science in general and near space ballooning in particular. If as a result, access to near space ballooning is stopped or limited, students who's only dream is to launch experiments into space will be denied the opportunity of reaching this dream by taking their first step into near space.
Gawker is carrying an expose on Mr. Heene from a former friend and it doesn't cast a favorable light on him. I can understand Mr. Heene's concern if the balloon got away from him and he wanted to get it back. That however, does not excuse reporting that his son was onboard as a way to get state and federal government to track it. Claiming your son is onboard also reflects a lack of forethought. What are you going to say once the balloon is recovered (and it will) and its discovered no one was onboard?
I hope the public realizes Mr. Heene is not the face near space exploration.
Friday, October 16, 2009
The system is simple and starts up as soon as you apply power. That means no waiting to boot a PC or load software.
Thursday, October 15, 2009
The launch takes place Saturday at 8 AM from trhe KWU campus. You should be able to track the flight at one of this webpages.
Onboard will be five KU BalloonSats and at least one experiment from the KWU Physics club.
I'll be flying the reuseable lunch bag tracker I'm developing for Popular Mechanics, an old backup tracker, and a module with a new flight computer. This module carries most of the science. It will measure cosmic rays, weather conditions, internal temperature, and several cameras, including still and video.
Friday, October 9, 2009
The CheapBot MagArm will allow robots to pick up slightly modified ping pong balls. This gives students the challenge of programming the robot to pick up stuff without spending more time trying to make the system work mechanically.
Thursday, October 8, 2009
The boards tested fine, so look for kits on Nearsys.com/catalog shortly.
Wednesday, October 7, 2009
I'm looking into hall effect sensors now as a way for the robot to detect the presence of a magnetic field. That should help the robot align its arm, because the objects it will pick up will be ping pong balls with small neo magnets glued inside (the bottom of the ball will have a cut hole so it doesn't roll).
Perhaps I can shoot the PCB for the arm tomorrow.
Tuesday, October 6, 2009
Monday, October 5, 2009
Sunday, October 4, 2009
The tracking modules based on the MicroTrak 300's had trouble getting packets to us during the chase. However, the APRS gateways put plenty of packets on the Internet. Um, this calls for some investigation. If you know of someone who can help me analyze the radiation pattern and strength of the transmitter, please let me know.
I'll post more information on Washburn's first near space flight in the next few days. There will be a full report on my website.
Friday, October 2, 2009
The three trackers are transmitting as KD4STH-4, -8, and -9. The frequency for all three is 144.390.
In addition, this mission will carry the thermopile telescope I designed. It also has a weather station like the kind I'm selling, two video cameras (one pointed up and the other pointed down), digital still camera recording horizontal pictures every 15 seconds, and an accelerometer.
I'm looking forward to a fun flight. If you're in the area, come on out.
Wednesday, September 30, 2009
Tuesday, September 29, 2009
I'm starting to pack kits. I began by creating a spreadsheet with a list of the parts and costs. After that, I'll copy the list of parts into a word document and print that out. I follow what's int he document to pack the bag with parts. I also write the number of items that goes into each bag. That way, after I collect the parts on the list, I do a final count before packing them into their bag. However, before packing each bag, I now affix a label on the outside of the bag with teh name of the kit.
The bag for the prox detector is a sandwich bag, since the PCB is six inches wide.
The Smart Proximity Detector is for any robot that can receive serial data. Look for it under Catalog at the NearSys.com website shortly. I have a video demonstration of a robot using the detector that I am completing. That video along with directions and a copy of the code will be available online for free.
Saturday, September 26, 2009
The flight computer is like a BalloonSat Easy with a built in radio and GPS Port. After building one, you just need to attach the antenna, batteries, and GPS receiver and you're ready to fly. The final kit will include memory (which the version 2.0 BalloonSat Easy doesn't) and a coax cable and wire for making the antenna. It will be my most expensive kit since it includes the $60 radio transmitter. But overall, it should be one of the least expensive ways to ow a flight computer suitable for near space missions.
One day, I hope to enter into the model rocetry field with a line of model satellite payloads.
Friday, September 25, 2009
I thought I'd just put the 556 on the o'scope in class and tune it up (adjust thwe PCB's pot to get the proper 38 kHz pulse). But I had forgotten that the o'scope would trigger on any signal, whether it was from the 10 hZ of the 38 kHz square wave.
I finally tapped into pin 5 of the 556 to see just the 38 kHz signal. It looks like on the next design, I'll add a test point to the PCB to make tuning the 38 kHz side easier.
Thursday, September 24, 2009
This means I need to get the book together (see my Citizen Scientist articles) for directions and recommendations. The book I plan to publish through Create Space. However, I'll need an ediotor to read over the book first.
Now if there was a way to make a camera kit.
Wednesday, September 23, 2009
Monday, September 21, 2009
With all the talk about the MIT flight that used a cell phone for tracking, I'm wondering about writing an article on using Find Me Spot to track. This would allow someone who does not have an amateur radio license to launch near spacecraft. Of course, the tracking unit would have to go up as a back pack with a Tickle Me Elmo to create a Find Me Elmo.
Sunday, September 20, 2009
Problem number one was the H-Bridges. With a code space of only 256 bytes, it was important to incorporate two H-Bridges into the design. That way it only takes two short lines of code to drive or steer the robot and the PICAXE could do other tasks simultaneously. But it takes four I/O pins to operate two H-Bridges. What could a robot controller do with one I/O pin?
My solution was to double-up the function of one of the I/O pins. It controls the drive of two motors and therefore leaves the robot controller with two I/O free pins. So now the robot can walk and chew gum at the same time. However, it can't pivot about its center - it has to turn centered on one wheel.
The turning subroutine has the robot taking turns pivoting on the left and right wheels. I call it psuedo-zero turn radius. Since it takes so little memory to turn the robot, the extra code space required doesn't fully offset the gains in the extra I/O.
Saturday, September 19, 2009
It's up to small businesses like NearSys to specialize in types of electronics that hobbyists might like to purchase.
Do we have a problem in the US that not enough people are doing hobbies?
Friday, September 18, 2009
Thursday, September 17, 2009
Wednesday, September 16, 2009
A ground test like this lets you find errors without leaving the ground (where it's a lot cheaper to correct).
Tuesday, September 15, 2009
The phototransistor and its collector resistor behaves like a voltage divider. In the non-conducting state, conventional current flows from the positive supply, throught the resistor, and to the robot's I/O port. This means a positive five volts is detected by the robot controller (AKA a logic high). When the phototransistor is conducting, current from the collector resistor flows through the phototransistor to ground. This leaves no current (or more accurately, very little current) to flow to the robot controller. As a result, the controller see less than 1.4 volts, or a logic low.
I read earlier today that the movie, Creation, which is about Charles Darwin, can't get an American company to distribute it. Amazing, we live in the 21st century, but some throw-backs are going to make it too contraversal to show a movie about Darwin's most important contribution to science.
Monday, September 14, 2009
I need to look up some information on Rocketman parachutes to finish this article for Popular Mechanics online.
Sunday, September 13, 2009
I built a thermal test chamber years ago that circulates cold air around a test subject with air fans. Dry ice is loaded into a metal in basket and then two smaller in baskets sit on top of the dry ice. The experiment sits on top the stacked baskets allowing cold air to flow around the experiment.
Right now the Popular Mechanics near space tracker is inside. I plan to let it chill for 30 minutes (at least) and compre the internal temperature of the reusable lunch sack to the outside air temperature. The dataloggers for this test are Hobos.
Saturday, September 12, 2009
The Pop Mech article I'm writing explains how to build a near space tracker inside of a reuseable lunch sack. This is similar to designs by NSTAR and TVNSP. The goal is to keep it cheap, but leave room for expansion and flexibility.
This afternoon I'll watch the movie 9. It takes place in a post-human world were humans are destroyed by their technology. Ummm, should I be building robots?
Friday, September 11, 2009
Now the PICAXE can't send enough current to all the IR LEDs (IREDs). So it triggers a transistor when then provides the power for the IREDs. A chromed ball above the IREDs (which are pointed inwards and up) will fan the IR out in all directions.
After completing this design, I'll build a PCB for a IR beacon detector that robots can use to locate beacons.
A beacon placed on a robot locates the robot. But a beacon can also be placed on a destination for the robot to find.
Thursday, September 10, 2009
The PICAXE cycles through all six frequencies until there are detections on both the left and right IREDs (the only time it runs through all six frequencies is if the IR detector doesn't ever detect a reflection). The PICAXE then sends a serial message with the range to the obstacles as thety appeared to the left and right IREDs. The range of dfistance is from 1 to 6, with a value of 7 indicating there was no reflection or that the obstacles are infinity far away.
The robot reads the data from the proximity detector as it needs to and then acts on the results.
Here's the code as it is currently written.
symbol RightDetect = B0
symbol LeftDetect = B1
symbol distance = B2
symbol counter = B3
symbol RightDistance = B4
symbol LeftDistance = B5
symbol left = 1
symbol right = 4
RightDistance = 7
LeftDistance = 7
for counter = 1 to 6
if RightDistance < 7 then CheckLeft
RightDetect = pin3 '0 = detect, 1 = no detect
pwmout 2 off
if RightDetect = 1 then CheckLeft
RightDistance = counter
if LeftDistance < 7 then FinishCheck
LeftDetect = pin3 '0 = detect, 1 = no detect
pwmout 2 off
if LeftDetect = 1 then FinishCheck
LeftDistance = counter
if LeftDistance < 7 then IsRight7
if RightDistance < 7 then Report
if counter > 1 then Check45
if counter > 2 then Check44
if counter > 3 then Check43
if counter > 4 then Check42
if counter > 5 then Check41
if counter > 6 then Check40
pwmout 2,24,50 ' 14 inches
pwmout 2,23,49 ' 10 inches
pwmout 2,23,48 ' 9 inches
pwmout 2,22,47 ' 6 inches
pwmout 2,22,45 ' 5 inches
pwmout 2,21,44 ' 3 inches
pwmout 2,21,43 ' 2 inches
Wednesday, September 9, 2009
Eventually I'll flash the IREDs at different frequencies to determine if the wall is located farther away or closer.
but first, I have to set my wait period between left and right flashes. I don't know how long the detector "remembers" that it saw a reflection.
Monday, September 7, 2009
Saturday, September 5, 2009
Friday, September 4, 2009
The batteries recommended are photo lithiums. I've used them before in near space.
Thursday, September 3, 2009
Wednesday, September 2, 2009
Vernier is popular in science classrooms.
Tuesday, September 1, 2009
Dist(in miles) = sqrt[height(in feet) X 1.5]
Multiple the altitude in feet by 1.5. Then take the square root of the answer. The distance to the horizon is in miles.
Since my eyes are 6 feet above the ground, I multiply 6 by 1.5 to get 9. The square root of 9 is 3. So the distance to the horizon for my eyes is three miles.
A near sapcecraft at 90,000 feet sees 367 miles to the horizon. Because of refraction, radio should reach a little bit further.
Monday, August 31, 2009
Saturday, August 29, 2009
Friday, August 28, 2009
The product is great, I encourage everyone to try it out.
Thursday, August 27, 2009
Wednesday, August 26, 2009
Tuesday, August 25, 2009
Monday, August 24, 2009
Sunday, August 23, 2009
Saturday, August 22, 2009
Of course its flat surfaces are another benefit.
The thickest it comes in is 10 mm. A 15 mm thick sheet would be great.
Friday, August 21, 2009
Thursday, August 20, 2009
Wednesday, August 19, 2009
Cut only with a sharp blade and only along the grain if you absolutely must use that dull blade once more.
Tuesday, August 18, 2009
Sunday, August 16, 2009
Saturday, August 15, 2009
The kinds of connectors I've used are Anderson Power Poles and Dean's Connectors.
Friday, August 14, 2009
Thursday, August 13, 2009
Wednesday, August 12, 2009
Bolting can be done with #2-56 hardware to keep it light, but you'll want washers to make the head of the bolts larger. Try using plastic (20 mil thick?) that you can purchase from hobby shops that sell model trains (or other construction type hobbies).
Tuesday, August 11, 2009
Monday, August 10, 2009
Sunday, August 9, 2009
Saturday, August 8, 2009
Friday, August 7, 2009
Thursday, August 6, 2009
Wednesday, August 5, 2009
If it can land without blowing apart, then you'll probably get the experiment back in one piece.
Monday, August 3, 2009
A BalloonSat not properly designed for the post-burst chaos is liable to open up or fall apart.
To test for this situation, tie cords to a broom handle and suspend your total BalloonSat (batteries included) from the cords just like it would be suspended from a near spacecraft. Hold the end of the broom handle away from your face and give the appartus a good shaking.
If your BalloonSat holds up, it's ready for the balloon burst and descent.
Sunday, August 2, 2009
Expect temperatures to drop to at least -60 deg F on ascent to near space. Your dry ice chamber shuld be able to get close. Brrrrrr!!!
Saturday, August 1, 2009
Friday, July 31, 2009
Uline makes a wide selection of tapes.
Avoid aluminum duct tape as it adds unnecessary weight and creates a heat shink to draw heat out.
Tuesday, July 28, 2009
I envision tis being used by an entire classroom.
Monday, July 27, 2009
There's a tape for gluing Cellfaom 88 together. Don't use that for a BalloonSat airframe, instead use a bead of hot glue. Then cut out any ports and openings. Afterwards you can wrap the airframe in thin colored tape.
Sunday, July 26, 2009
I've finished the initial design of a flight computer that incorporates a radio. Just plug the GPS in and you're ready to go. I hope to get a test board sent to BatchPCB within a week. I call the design the NearSys UltraLight.
Sunday, July 19, 2009
NearSys 09E reached an altitude of around 80,000 feet. The exact altitude if not known becuase the GPS was acting up. The backup tracker only produced five posits on descent. It transmits now, so I checked the battery and found it was 8.0 volts (nominal 7.2 V lithium). So I suspect the capsule was accidentally shut off or it has a bad power switch. I'll get this debugged before the next mission. This is why NearSys flies two independent trackers on every mission.
Recovery occured in Garnett, where at least three other capsules recovered. This has got to be the biggest news for this town!
A homeowner was setting his sprinkler when he heard a rustle in his tree. He turned around to see the capsule and parachute descend along the side of his tree. He was 10 feet away when this happened. It looks like the downward camera can see him shortly before landing.
This is the highest image, taken around 80,000 feet. That cumulonimbus cloud was on the horizon as the near spacecraft lifted off. At this altitude we're so high that we can see the horizon beyond the cloud.
So I'm looking for a another opportunity to fly. I have a thermopile telescope to test.
Wednesday, July 15, 2009
I'm launching a near spacecraft carrying the following experiments.
Still Digital Camera
Two Digital Video Cameras
Mark Conner is predicting great weather for Saturday's launch. I'm really looking forward to GPSL this year. I'm the only person to attend them all.
Onwards and Upwards
Tuesday, July 14, 2009
Blog's have very much a single direction. I post updates to them for people to read. While people can make comments, their input is not as significant as my initial posts.
Wiki's are very bi-directional and collaborative. Regardless of who creates an entry, everyone is treated as an equal. in fact everyone is expected to add input equally.
How would I use Blogs and Wikis?
I would use a blog to post information, notes, link, and videos to my students. If they have a question, they could make a comment. But notice the blog is very teacher centered.
I would set up a wiki for teams of students to talk to each other. It allows them to collaborate and learn together.