Little Miss Destruction


Peanut Tin of Terror


Sterylite 6000


Fluffy


Kudu




Open Source Quad Kit $110


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February 18 - Open Source Quad Frame

I have been working on a four legged robot frame that supports the parallax servo controller and the gadget gangster propeller platform USB. The frame is small, cheap, and easy to assemble. I made everything open source, so if anyone wants to take the design and copy it, please do so with my blessing.

One thing I have learned about robots is that if you can iterate on a design it gets much better. This probably seems like a really simple thing, but actually its my fifth version of the design. The first one worked, but this one is much better. The next iteration I think I will try to add sensors on the feet and mounting holes for an Axon MCU.

You can see it in action below. It works pretty well.



January 27 - I Have Wrecked A Lot of Servos

Over the years I have damaged or destroyed a lot of servos. So much so that I decided to add a few notes about how to preserve your servos in my servo guide. Everytime I have wrecked a servo I try to think of what can do to avoid the problem next time.

January 20 - LMD 2.0?

My sister emailed to say that her son was interested in working on a robot to battle in Robogames 2012. Little Miss Destruction, his robot for 2011, may not look that impressive but for a robot mostly designed and built by a kid I think it is pretty good. I know my nephew has some ideas to improve LMD. I am just excited that he is interested enough to keep working on it. I will update the page to show the changes we make.

January 16 - Metropolis II

This weekend I went the Los Angeles Contemporary Art Museum to see Metropolis II. It was, as they say, fun for the whole family. If you have never seen this thing you should check it out here. Of course it is much more impressive in person.

January 8 - Working on Quokka

I spent this weekend doing some tests on John Frizel's robot Otto and Wanderer. Wanderer is OK from its last battle, but something is wrong with Otto. I also tried to imprvoe the 3:1 gait of Quokka. I still don't have a nice steady 3:1 gait for the robot, but for fun I shot a little video of it clomping around with it's 2:2 gait.

I put a video of Wanderer being tested at an event in Petaluma up here. Wanderer ia a 1 lb autonomous combat robot.

January 3 - Arduino at Radio Shack

After Christmas I went to Radio Shack to get batteries for the kids toys. Of course I took a peak at the electronics section. I saw that they now carry Propeller and Arduino boards. As someone who grew up tinkering with electronics from Radio Shack I found this really exciting. Pretty much every component you need for the electronics of the type of robots I make is available at a strip mall near me.

I asked the sales clerk about this and she said they had Arduinos, but they never sell. That is sad. On the Radio Shack board I saw two complaints. First, Radio Shack charges $35 a board as opposed to the $30 it costs at some online stores. Those stores probably charge about $10 shipping, and you have to wait a week.

The other complaint was that the sales clerk couldn't help the customer when they were having problems with the compiler. Apparently this person thought that someone who sold batteries was going to provide that kind of technical support. I happen to be lucky enough to live by All Electronics, and even at a specialty store like that you are not going to get that kind of technical support from sales people.

Someone complained on the forum that the sales clerk didn't even understand what DIY meant! Isn't it ironic that there is someone out there that thinks they are "do it yourself" yet they expect the clerk to show them how? I think that community is so used to buying off the Internet that they don't understand the convenience of having important components close at hand and easily available.

Decemeber 28 - Brush Robot

For Christmas, my father in law got my son a brush robot kit. With all the robots around I'm surprised it interested him. He doesn't take a lot of interest in the robots I build. But I think he really liked something he made himself. Also, it was a pretty cool kit.

December 23 - Air Manta

There are some robot builders that are an inspiration to me.  Festo is a great example of this.  I have gathered together a page of their biologically inspired robots.   You can see more here.  



December 18 - RQ-170

I am fascinated with the technical aspects of the story about RQ-170 drone that landed in Iran.  I don’t think people know what actually happened to the drone, and you should assume that both sides have an incentive to tell stories that are not accurate.  

Assuming that the drone was fooled, I have seen two different descriptions of how it might have been done.  In both scenarios the satellite controls for the drone were jammed.  Then, according to the first hypothesis, the Iranians imitated the line of sight landing controls for the drone and just landed.  The other scenario is that they jammed encrypted GPS and then spoofed un-encripted GPS to get the drone to land where they wanted under the drones own control.  

I am really interested in this because of what I learned from building an autonomous robot that fights.   Although that robot has lost fights by not being able to take a punch, the hardest part really is getting robot sensing to work in a hostile environment.    

Robot sensing is difficult in general.  It becomes much harder when the sensors are likely to get damaged or interfered with.  For example, a color sensor will return crazy values if the robot is flipped over and you are sampling ambient light.  A broken connection will cause an ultrasonic sensor can either cause a sampling thread to hang or return an in plausible distance measurement.   One thing I have learned to do is to program Peanut to sample every sensor, but not to have the program fail if the sensor is broken.  The next step is to get the robot to make a decision based on what information is available when there is a chance that any sensor is not valid.  

It seems like you need to do two things.  First you need to evaluate how plausible a sensor reading is, and discount it if it looks bad.  Second, you need to have a decision loop that can work with whatever sensor information is available.  That’s obviously very similar to what has to be done on drones in hostile environments.  

December 6 - Servo Bundle Sale at Servo City

There is a really good sale right now at Servo City. You have to buy servos in bundles of four or more but you can get up 28% off on HiTec servos. These include some of my favorite servos like the HS-5685MH at a good discount. You can mix and match different hitec servo types. This offer only lasts until December 8th, so you only have two days to take advantage of it.


December 4 - Useful Tools

Almost the first thing I ever put on this site was a list of the tools that I thought were useful for making robots. Learning what was useful has been a trial and error process, and some of the tools I used to use a lot I use less now. One particular piece of equipment has become indispensible: a smart charger with an equalizer.

This weekend I thought I would trty to get three walking robots going at the same time. The three robots used between them a NiCD, a NiMH, a LiPO and LiFE battery. My old robot Fluffy uses a NiCD for the microcontroller and an NiMH for the servos. Quokka uses a single 7.4v 4000 maH LiPO. And my small open source quad works quite nicely with a 6.6v 1800 maH LiFE battery. The 7.4v of a LiPO would wear out small cheap servos quite quickly, 6.6v is more friendly. Anyway, all these different types of batteries take a different type of charging. And in the case of a Lithium battery, it takes a balncer as well. I can charge all of them with one smart controllable charger, the Triton.

November 19 - Robots Across the Pacific

Liquid Robotics is launching a set of wave glider robots that will try to cross the pacific. These robots are amazing.

November 9 - Otto Back From Combots

The Peanut Tin of Terror's nemesis Otto has returned from Combots 2011. Otto defeated Wallie in autonomous combat 2-1, but took some damage in the process, I have learned so much about working with metal in the last year. I think I would like to see if I can help come up with a replacement robot for this robot.



October 30 - Help from Big Blue Saw

I have been using Big Blue Saw to make pieces for a quad kit. I am trying to make the cheapest, simplest walking robot I can.

One nice thing about something that is simple and cheap is that you can try it a few times and experiment. So I'm trying different configurations to see what is best, including different types and thicknesses of aluminum. I'm trying to find a balance between rigidity, bendable-ness, and ease with which it can be cut. I have had some questions about different metals.

I thought maybe I could find some help from some forum or something but I didn't have any luck. It's hard to find places where people will answer questions who are really expert. Somebody answers your question, but often it's just a person who knows a little trying to be helpful.

So I thought I would just ask the people who cut the metal at Big Blue Saw. Simon at Big Blue Saw has been able to give me some suggestions about what metal to use and how to handle it. It's very nice to be able to ask someone knows what he is talking about.

October 18 - Sonar vs Lasers

I never put much time into working with infrared sensors. I tried some early versions of sonar sensors (which were quite expensive) and then got a Ping sonar sensor and I never really looked back. In my opinion sonar sensors are superior to IR ones, the only benefit IR has is that it is cheaper.

I have been using sonar for a long time now but I can see that for hobby robots it is going to be eclipsed by visual systems. The Kinect is amazing for robots because it gives you a depth field in front of you in real time. While the Kinect is kind of heavy and complicated for the kind of robots I make, the Parallax Laser Range Finder may be a reasonable alternative.

Both the Kinect and LRF work on a similar principal. They both project out an image and use a camera to predict distance based on the location of the image. In the case of the Kinect it projects out a grid in the infrared spectrum. The LRF uses a laser pointer that creates a red blob. By triangulating where these images show up on a camera you can make a very good estimate of distance quickly.

There are other techniques that may become increasingly useful, such as dot-cloud calculations. Using Sonar works pretty well, but it can only have a very limited resolution because sound disperses. Also, sound has a limited range. Visual techniques can give you a more precise and distant topology then you can get from sonar. It can let you see the shape of things.

These new visual techniques are leveraging cheap digital cameras and the low power processors that are powerful enough to do visual processing. Essentially the technology of smart phones is making new things possible (and cheap) for robots.

October 6 - Combots 2011

Combots is happening this month on October 28th. I know that Otto and Wallie will be competing but unfortunately I will not be able to attend because of my work.

John Frizell asked me to send up the Peanut Tin of Terror but I don't think I am going to send it up. If my robot was as well designed as John's I think it would be possible to just mail it and have someone flip the switch. The problem is that the PTT is kind of a mess. There really is just a nest of wires inside that can with a bunch of electronics that rattle around loosely. There are two batteries that need to be charged, one that is Lithium Ion, one that is Nickel Metal Hydride. The steps to get it started our complicated, a lot more complicated then they ought to be.

September 29 - Terror Drones

Apparently people have woken up to the fact that a lot of the basic technology of military drones can be recreated by hobbyists. If you look at some of the projects at DIY drones you will realize this is not an exaggeration. Small flying drones like the type the army use for observation can be bought or built. Larger aircraft are harder, but even hobby kit planes get very big. And if you google pulse jet you will realize that there are a surprising number of people who know how to build the engine for a cruise missile. You don't need a lot of imagination to see where that could go.

The FBI has caught a would-beterrorist who was trying to do something like that, putting explosives in a large RC airplane. Now, inevitably, people are going to start to worry about large radio controlled and unmanned aircraft. And that worries me.

When I started to make robots, one of the things I thought about doing was using servos to add guidance to a model rocket. It turns out this is quite illegal in the United States unless you get some special permits. Apparently long ago someone thought to regulate guided rockets out of hobby existence. They could easily do something similar with guided planes.

As robotic devices become more capable they inevitably will become more dangerous. It's not going to take long for someone to realize that a self driving car can be made into a self driving car bomb. I'm not interested in cars or planes, but I do like to build walking robots. I would build a robot that was much bigger if I knew how, probably big enough that someone would consider it dangerous. I don't want people to try and ban me from doing it, or make so difficult to get permission that no hobbyist would bother.

If you look at what people are doing today with unmanned boats, unmanned submersibles, drones and robots you can see that they are developing incredible technology. Like the early personal computer, this technology is driven by students and hobbyists, not large corporations. Trying to regulate it to make it "safe" could kill the movement, or at least keep it out of the hands of college students with limited funds.

There will always be some frontier of technology that has the potential for danger. One of the reasons why the United States has usually stayed in the forefront of new technology is that we have a government that trusts its people. We never banned copy machines, or modems. We let people have guns. I think we need to be a country that lets people build drones. We need to be a country that lets people make dangerous things, or will probably stop being country that makes things at all.

September 5 - OSK with a Ping

Here is a picture of my open source quad with a ping sensor mounted. All robots look better with a head.

September 2 - Open Source Kit

I made a CAD template that you can turn into a robot with just scissors and a screw driver. I was trying to make the simplest, cheapest thing I could come up with that could be easily reproduced. The basic hardware seems sorted so now I will try to add some basic software-- probably just a walking gait for now. If I can get a basic version working my hope is to make the whole thing open source with just a source / attribution license. Software and hardware.

It's also kind of small and cute.

August 13- A Brief Update

Late summer is a very busy time with me in my work (day job) so it has been hard to put up as many updates as I would like. But here are some of things I have been up to:

August 9 - Bilibot

Two of the coolest things happening in Robots right now are the ROS operating system and Microsoft Kinect. I have made fun of Microsoft's attempts to make software for robots, but in ROS Willow garage has come up with something as ambitious that seems actually useful.

Kinect was made as a human interface for the Xbox. As a game developer I have been aware of the Kinect for years, but I didn't have the imagination to see it's application for robotics. The depth perception feature of the Kinect makes it almost like a cheap indoor lidar. Between Kinect and some of the point cloud detection techniques (which you can see supported in ROS) I think we are going to see a huge improvement in indoor navigation.

Which brings me to the Bilibot. The Bilibot combines ROS and the Kinect into a relatively inexpensive platform. It is probably more for researcher then robot hobbyists. But if you want to see where robots are going, check out this robot that combines two of the most interesting technologies.

August 3 - Help Robogames Win a Grant

Here is an announcement from the organizers of Robogames.

Help us win $25,000 for kids classes!

RoboGames is up for a $25,000 grant to help bring robotics classes to underprivileged middle schoolers around the San Francisco Bay Area, and you can help! Pepsi is offering large grants to non-profits such as the Robotics Society (the parent organization of RoboGames), but only the top few ideas will win.

You don't need to give us any money, you just need to vote! Please help us get funding to get more kids building robots for the 2012 games! We are poised to make this a great year for community centers, under funded schools, and a whole slew of other folks with your help! If we win the voting, we can put robots in the hands of about 120 kids and provide them with teachers for a full semester of after-school instruction. All leading up to them competing at RoboGames. The classes will get kids autonomous robots, and teach them how to program and build the robots to compete in multiple events in next April's event.

And neither you nor the kids have to pay a cent!

Here's the link to vote: http://pep.si/nHlOZZ or you can vote by texting 107947 to Pepsi (73774) to vote from your mobile phone.

And you can vote once per day! So vote today, tomorrow, and Thursday! This will barely take any time at all, but can impact the lives of a lot of kids who'd never get to learn about robotics otherwise. We can inspire them to keep studying STEM (science, technology, engineering and math), and all you have to do is vote!

Thanks for your time! And please be kind and forward or tweet this message.

July 20 - Sonoma Ant Wars

From Kevin French:

Hello Everyone,

This is your Coordinator speaking...uuuuuuhhhhh....we are on route to a fine battle in Sonoma County....uuuuuuhhhhhh (ok enough for the flight captain talk) For those of you who didn't know, we have an event this Saturday July 23rd 2011. If you haven't registered via the website and intend to compete, please do. If you wish to watch, know that admission is free (its HobbyTown USA for crying out loud). oh! and an important note FLAMETHROWER ROBOTS ALLOWED! We have one CO2 extinguisher on hand and prizes to boot. Sonoma Ant Wars Registration closes in 2 days!

How to register: http://robogames.net/registration/event/view/14
After you login, click RoboGames - Event Registration in the top left-hand corner

Payment is made at the event but please do register so we know how many people are planning on coming ahead of time

Who: Insect Weight Classes
  • 150 Gram Combat ($25 entry)
  • 1 Pound Combat ($25 entry)
  • 3 Pound Combat ($25 entry)
  • 1 Pound Autonomous Combat (Free Entry)
  • 3 Pound Autonomous Combat (Free Entry)
When: Saturday, July 23rd 2011
  • 10:00am-10:45am Registration
  • 11:30am First Match
  • 5:00pm Approximate Endtime
Where: HobbyTown USA
171 North McDowell Boulevard
Petaluma, CA 94954-2304

Directions:
Coming from Highway 101 Northbound
1. Take the E WASHINGTON ST exit toward CENTRAL PETALUMA.
2. Turn RIGHT onto E WASHINGTON ST.
3. Take the 1st LEFT onto N MCDOWELL BLVD.
4. 171 N MCDOWELL BLVD is on the LEFT.
Coming from Highway 101 Southbound
1. Take the E WASHINGTON ST exit toward CENTRAL PETALUMA.
2. Turn LEFT onto E WASHINGTON ST.
3. Turn LEFT onto N MCDOWELL BLVD.
4. 171 N MCDOWELL BLVD is on the LEFT.

Why: We have the technology

A big thank you goes out to both David Calkins and Kevin Hjelden for letting us use the RoboGames registration system. Sonoma Ant Wars Registration is Open!


HAPPY BUILDING!
~Kevin S. French

If you are in the enter you should try and watch this. If you've got a robot and you are in the area, you should bring it, especially if it has a flamethrower.

July 17 - Kudu's Frame

I spent some time this weekend adding the new chassis/ frame piece for Kudu.

July 13 - Check this out!

I got a new chassis piece for Kudu from Big Blue Saw. I have been working on designing this piece for a while. I recently ordered it and now it has arrived.

This chassis should allow me to space out Kudu's legs so that it will have a wider stance. That should make it less likely to fall over on it's side. And it should have an easier time making turns, although I don't think Kudu is ever going to have a great turing radius.

This is 1/8" aluminum cut by a waterjet according to a .dxf file. I think it looks kinda cool. It's a long way from using shoe boxes for chassis pieces.

July 8 - Ripple Gait

Since Kudu is very narrow, he often tips on his side at obstcles. To give him more stabillity I tried a ripple gait that keeps three feet on the ground at all times. I also plan to make his chassis wider, but for now this was an interesting experiment.





July 1 - Turnigy LiPos

Before Robogames this year I got a very inexpensive 2.4 Ghz RC Tx/RX combo from Hobby King. It was very off-brand but the price was also really cheap. For autonomous combat all I really need an RC transmitter to do is receive the signal to turn the robot on and to turn the robot off. I don't need to mix channels or adjust the sensitivity so it made sense to experiment with a cheaper transmitter.

It turned out the radio I got worked great. It was missing some features, and the receiver was a bit bulky, but otherwise it worked for my purposes. And it was a lot cheaper, like more than half the price of name brands.

This made me think I should try a Hobby King off brand batteries. LiPo batteries are really expensive, if I could find a cheaper brand I could save a lot.

A Turnigy 7.4v 4000mAh battery costs about $20, plus shipping which is a lot if you are just buying one. By comparison the same battery as a Venom brand is about $40. But is it worth it to buy off brand LiPos? As with servos, the performance of batteries may not always be as good as advertised. Hobby King has really cheap LiPos that they say only will work for about twenty charges. I don't know why you would want batteries that only work for that low number of charges. The idea that they even sell batteries like that is a little worrying.

Another problem with LiPos is that they can catch fire in extreme circumstances. I have never had anything happen like that, but then I have never tried an off brand battery. I got two of these Turnigy batteries and I will try putting them into some robots. If they work out well then I will be able to recommend them. If they don't I will be able to warn you before you buy them.


June 25 - Kudu

Last weekend I got Kudu up and running again. In particular I got it to go untethered by putting a jumper on it so that the servo controller could run on battery power. This gave me a chance to try running it on the open floor.

Kudu is interesting to me because it is a quad with flat wide feet. In the long run I think that is going to make it better for walking with a 2:2 gait. It has some problems though. The body is just a rail and the legs are set very close together. That means that the robot can fall on its side. Also, it has trouble turning.

I am going to try giving the robot a wider body to see if that helps with turning and stability. I know I can further improve it by adding more degrees of freedom (servos) to the legs. Adding servos is something I would only do after I exhaust other options. I always try to use fewer servos because the fewer you have the cheaper, lighter, and more reliable your robot usually is. I am really excited about how Kudu is coming along though.

June 12 - Quokka

Quokka is the quad that I hoped to enter into MechWars at this year's Robogames. I had too much going on and I didn't get that robot ready to enter. Now I am sort of getting it done on the backburner. I have gotten the robot so it works reasonably under remote control. The next steps would be to add pellet guns, pressure sensors, and a camera. There should be time to get to that for next year.

Getting it walking under remote control is another chance to learn about walking quads. Quokka's chassis was designed by Quantum Robotics, and it is a fairly conventional layout for a quad. Four legs with three degrees of freedom. Two degrees of vertical freedom, one horizontal on each leg. Essentially it is an 18 DOF hexapod with two fewer legs. Like a hexapod, it has feet that end in narrow points.

I think if you are going to do a quad you are better off with big flat feet like the ones most biped robots have. Little pointy feet work great for hexapods because you can have a gait of alternating tripods. You can have a tripod gait for a quad, but it slower because you have to have a cycle where you are getting the feet into position and not moving the body forward. In nature four legged animals do not alternate between tripod stances.

June 5 - A Machined Shell for Little Miss Destruction

I made the body for Little Miss Destruction by cutting a pattern I made in a CAD program by hand. You can see the step on the page for that robot. Since I had it as a .cad file, I thought I would try to get it fabricated at the Big Blue Saw. They cut the pattern for me with a water jet machining with much better results.

You can see that I got the pattern back cut perfectly with all the holes in the right place. I bent at the creases, and now I have a new body for another robot or a replacement. Also, this way I can try changes and have it made again with improvements without starting from scratch. Or if somebody wants the cut sheet metal or the use pattern it is easy to offer it. Having robot parts machined like this could really improve my robots. It's a long way from using a plastic shoebox for the body as I did on Sterylite 6000.

I have a new body for another robot or a replacement. Also, this way I can try changes and have it made again with improvements without starting from scratch. Or if somebody wants the cut sheet metal or the use pattern it is easy to offer it. Having robot parts machined like this could really improve my robots. It's a long way from using a plastic shoebox for the body as I did on Sterylite 6000.