Pictures :)

A few posts ago I mentioned I got some new stuff, and promised pictures, well, here they are:

My snomobiles:

 

The pictures are kind of deceiving, the track looks pretty small, but it is actually 8ish inches long

 

And here are a cupple pics of the new A2 (they are pretty bad, the lighting was not great, and they were taken on an iPod)

I also have some videos, but they need to be uploaded to youtube, and some better pics taken by the camera mounted on the bot, but those are still on a memory card. Time kinda gets away from you sometimes.

Mis(guided)sile first peek

Here are a cupple pics of the very first little bit of progress on my missile project:

The missile as it sits right now:

 How I hope the control fins will work, two linked together in the nose cone with a servo powering them, and two in the body, each with their own servos, to control roll and yaw, with microcontroler board shown.

All of the componts I have now sitting together.

I have not really gotten further than that, I picked up some stepper motors and an old scanner over theweekend, and my next project will probably be a plotter built out of those. Either that, or that oragami ball rc thingamajig I mentioned last post. Project officially added to my pile/list of half baked and half finished projects laying about my room :)

Rambling #5 (thoughts on bots)

I was browsing Hackaday a little while ago, and I came across This homebrew guided rocket and it looked pretty cool. I have a few model rockets and appropriate engines for them, some micro servos, a micro magician microcontroler and a few one cell lipo batterys from some cheap RC helis. 9 and 10 DOF IMUs are cheap and so are single and 3 axis gyros on ebay, and after seing the results of their rocket, I think a gyro or 3 is deffinately necessary instead of an accelerometer, altho I might make use of one of those too (the micro magician has one on board) So I have, or can soon have all the parts necessary to try my hand at building one of those. My father has been encouraging me to try building things other than various takes on obsitical avoidance, and I think this could be cool. My rocket body is a bit smaller than the one they used, so I am contemplating straping on another two rocket engines to the base of my Mis(Guided)Sile to give me a bit more thrust, and either using rear-ejection parachutes, much like this:

or none at all, after all, this IS missile, and after having a look at their rocket after it's flight, I dont know how well it would survive even with a parachute...

I have also been thinking about building a propeller powered missile/airplane hybrid using a rear mounted brushless motor like This one swinging a large prop to give me huge amount of thrust, 4 oversized rear fins, sorta acting like really small wings, and probably four fins at the front for pich/yaw, much like the sidewinder

The difference with mine, is I will have 2 fins in the middle, linked together to give me roll control, thus enabling me to have only 3 servos on board (each controling two fins for each degree of freedom, simplifying control, and saving on weight) I think if I do some looking around I should be able to get a motor/esc/prop/battery combo that will give me better than 1.5 to 1 thrust to weight ratio for the whole thing, enabling me to have it take off vertically and fly for a bit longer than the estes rocket motors.

Also possibly coming down the pipe, project wise are:
1. fabbing up a better mounting bracket for Going Whole HOG, letting me take it to some higher speeds without worrying about it coming apart, and possibly automating the thing, which would make it my fastest obstical avoider to date (Lets see if those picaxes REALLY do run at 64Mhz...)

2. As my last post said, I got a new chassis for AutoSquared, so when I get some time, I will get it posted on LMR, right now all it does is avoid stuff, but with my compass and GPS in hand I hope to change that soon...

3. One of these:

Except in a blue PAPER! Origami shell. Not really sure if it will work, but it will be interesting weather it works or not. probably going to be just RC not a robot (someone find me a sensor capible of seeing thru blue paper, and I will make it autonomus....

4. The missiles I mentioned in this post hopefully....

5. Possibly that electric bike hub motor powered big outdoor robot (if that thing ever makes it into the real world I am totally mounting a laser sighted paintball gun or potato cannon on it. :)

6. A 2 DOF hexapod ( I have all the servos I need, and I do already have 2 and 4 legged bots under my belt, and now I need more legs.)

7. giving my quadcopter a new body, and a pan/tilt camera with live feed down to the ground. I will have a seperate tx/rx controling the pan/tilt so I can focus on flying and someone else can get some footage.

8. at some point I might finish up GPS (my other outdoor bot)


One last thing before I sign off, If you are an FBI agent or anything, and are adding me to your watch list because I mentioned making small missiles, do not worry about it, if they ever get made, I am not going to be doing anything devious with them, all they will ever amount to is a slightly stabilized/ angle holding projectiles, or funny looking RC airplanes. But feel free to keep dropping by, I appreciate the page views :)

A Quick Update

It feels like it has been a while since I posted anything, I have been doing a lot of school; according to the native beings that inhabit this planet, apparently school is more important than building robots and posting stuff about them, or something like that. Anyway, while I was away I got some cool stuff, another chassis for autosquared, with some really big wheels, two remote controled snowmobiles to take the treads from and a new (to me) computer, two serial ports, 3 parallel, two screens, lots of usb, a few firewire, and five disc drives to round things out. I am most excited about the two serial ports, cause now I can program multipule picaxes without having to swich cables, and the two screens (arranged vertically instead of the usuall side by side, because I use the comp mostly for programing, and programs tend to be MUCH longer than they are wide) for now I can have a lot more of my code visible, and/or code and have a refrence PDF open at the same time. Soon I will have some pictures up of all my aquisitions, and hopefully a panorama of my lair, uh, room.

New bot up at Letsmakerobots.com

I finished posting a new bot on LMR a little while ago: AutoSquared was going to be a testbed for some outdoor robotics while GPS waits for some wheels etc. But the motor burnt out (cheap rc car..) So all it does is avoids stuff in an outdoor enviroment (that is all I got it to do before the motor burnt out.) Still an intersting read I think.

Kinder SUPPRISE

I bought a kinder supprise a little while ago, and in it was the coolest thing I have ever seen stuffed into one of those little plastic capsules. I popped it open, and inside were 3 plastic pieces, and some plasticised sheets with score marks in them all rolled up. I took out the instructions, which told you to fold along the various marks, and insert the plastic pieces in various places. what you got at the end was a small (but really big compared to the little container it came in) airplane. It does not fly very well, but the thought that must have gone into designing that was unbelievable. I was amazed.

Awesome Hexapod

I saw a link to this beauty on letsmakerobots, and I just had to post it here. Mind blowingly awesome, and I like the dubstep too...

Rambling #4

Lately I have been thinking about flamethrowers a bit, and I have come to the conclusion that if/when someone gets around to making a nice fairly battle-ready exoskeleton, that to combine the two would make a formidable weapon, if you look at it, they complement each others weaknesses and stregnths quite well. One of the main things keeping exoskeletons from appearing in anything but tethered forms is their large power consumption, and untill someone invents a usable arc reactor small enough to mount on one, the next best thing is gasoline. It is fairly abundant, very power-dense, and we have tech now that turns it into useful power. But there is the argument that having a big tank of gas on your back might not be a super good idea, after all, you DO have a big tank of gas on your back. However, the flamethrower requires a big tank of gas anyway. Another thing: the two big downsides of flamethrowers is 1, you need to get close to battle in order to use it effectively, exposing you to enemy fire.(armoured exoskeleton anyone?) and 2, flamethrowers are HEAVY, and even then, they do not have that much fuel capacity. What are the main things about exoskeletons? improving stamina and (here it comes...) Improving weight handling capacity! So you have a weapon with lots of fuel for burning stuff, armour that lets you get close enough to acutally use it, and the drawbacks common to both designs fairly accounted for.
By the way I am not talking about these lame propane powered flamethrowers (as cool as they are)

No, I am talking about REAL flamethrowers:

And REAL exoskeletons:

Food for thought.

Rambling #3 (thoughts on bots)

I recently purchased an Adafruit Ultimate GPS and a cheap ebay compass sensor in persuit of building a serious outdoor UGV. I started a while ago a largish outdoor platform baised on drill motors, you can have a look at that Here but I am incresingly having some doubts that it will ever be finished. I built the bot with two used drill motors, and two new ones, and after some testing, I found that one of the used ones was nearly burnt out, and sucked a HUGE amount of current, it still spins, generally is on it's way out. Normally I would have replaced it, and got on with life, but by the time I found out, I had made that nice steel shell, and riveted it together, so replacing is not an option, as I would have to tear apart the intire bot. Not going to happen. Lessons learned: always design to take apart. I knew this, but I guess I just had to learn it the hard way. Anyway, back to the rant, I think, no problem, I will just put one of my HUGE 35 Ah 12 v SLAs in the bot, but now I am worryed that my 1/6 RC truck wheels will not stand up to the weight. No problem, just buy some 6" lawnmower wheel, and attach those to the drill shafts. Not so fast, the lawnmower wheels have holes in the center that are too big. So here the bot sits, with no suitable wheels, or power supply. Doing a little thinking and I am debating moving to a bigger platform still, using This electric bike wheel (I already have one from building an electric bike, but that is a story for another time.) As a rear/front wheel on a trike (rear or front will depend on weather I am using a conventional or tadpole style trike.) Having some experence with this wheel, I know that the 26" will be a bit much for a robot that weighs a cupple hundred pounds, I do not want to hurt anything/body by crashing into them with a very heavy robot trike going 35 km/h, that would be bad. Anyway, I was thinking I could put either a 20" BMX wheel or a dirt bike wheel of some sort on the electric hub and use that as my main drive system.
The problem is steering, I have weighed a few options, including using two drill motors for the other wheels and having a free swinging "tail" with the bike wheel on it, varing the speed of the drill motors would cause the tail to turn one way or the other. Pros: steering would be simple (just like a differential drive robot), three wheel drive, simplistic mechanical design, very little to go wrong. Cons: lots of math to figure out the size of wheels I need to ballence the speeds of different motors, and figuring out how much to vary the speeds of all three motors.
Another option would be to have the bike wheel on a tail, but have the tail coupled to a motor, and a feedback sensor (probably a variable resistor) so I could actively steer the tail. Pros: fairly easy steering, no math to worry about. Cons: finding a cheap motor that is powerful enough (maybe a windsheild wiper motor from a old truck or something) mechanics for coupling the steering motor to the fork might get tricky, having to hack a servo into a REALLY powerful servo, a bit less sturdy, no three wheel drive.
I could also have kinda the same setup, but have the tail mounted to the chassis and have the non-driven wheels turn. Same pros and cons as above.

Food for thought. I will leave you with these pictures.

Going Whole HOG is finished!

Well, my HOG drive platform v1 is finished, documented and posted on letsmakerobots, check it out at Going Whole HOG

Cheapness and paintball

I have a Spyder Victor paintball marker, and it is not a bad gun really, it was pretty cheap, and it gets me out on the field. I love my spyder, but I used to wish I had a longer barrel, the stock one was just not cutting it. I am a bit poor right now, and I balked at the ~$40 price tag of a nice barrel. Having just built a paintball cannon for my friend, I knew that 1/2" class 200 (thin walled) pipe fit .68 cal paintballs just fine, I also have acess to a lathe, so I figured, what the heck, I will give it a try. I measured my stock barrel's diamiter, and the legnth of the part that screws into the gun, chucked up some pipe in the lathe, and here is what I got:

admittedly, the white plastic looks a bit cheesy, but I can paint it later if I really feel like it, and the price is right ( you can get 20' of pipe (yes feet not inches) from any self-respecting hardware store for less than $5) the barrel might be a little long, but I can always cut it down later if I need to. I fired a few test shots, and it seems to work fine, no chopping, and better accuaricy.
You might have also noticed that in the pic I have a 48cu.in. HPA tank screwed onto my gun. Also in the persuit of money-saving, I purchased it and the fill station you can also see in the pic, tank was ~$40 and the fill station was ~$20 from amazon.com and ebay respectively. The fill station screws onto a scuba tank, and lets you fill your paintball tank anywhere you can lug a scuba tank. I borrowed a scuba tank from a friend, and since I can get it filled for free, I will have paid for my purchases in 6 fills, not bad considering I plan to go more than 6 times in the future, and my a few of my friends who do not want to shell out for all the new stuff said they would buy HPA tanks and buy fills from me for ~$2-$3. Doing more with less FTW!

Rambling #2 (Thoughts on Bots)

What do you get when you cross this Gripper

 and a quadroped like this?

Well, I don't know, you could get a number of things, but, I propose that you could have the makings of a pretty sweet wall climbing robot. Just get 4 of those grippers, mount them on the feet of your quadroped, and alternate "ungriping" one foot while the other 3 are stuck, moving it forward a bit, planting it firmly on the surface, sucking all the air out agin and repeating for each leg. It would not work on smooth surfaces like glass, but deffenately on brick/concrete walls, and maybe even on drywall.

Rambling #1 (Thoughts on Bots)

I have been interested in mini-sumo for a while, and I was thinking about how I could make an (almost) unbeatible robot. I have come to the conclusion that competeveness comes down to a cupple important things: traction, low profile fronts (traction does no good if the other guy gets under you and ruins it all.) quick response time while searching, and just enough power to push the other guy out. Ideally, tank treads covering the whole 100sq.cm (or almost anyway) with a scoop that deploys down would be the best (have a look at "the beast") However, building something like that is out of the question for most hobbiests, so I have come up with what I think would be almost as good, namely a walker. Now before you call me crazy have a look at this pic, and see that the walker I propose is not your average biped.

As you can see, the walker has a shell that moves around a round inner piece in a oval fassion. To see a more detailed discription of how this works, have a look at this link. This bot was not built by me, but it explains the walking method rather well. Anyway, the two pieces (circle and shell) need to have the same area, so it has equal traction when it is up as down (the importantce of this is evedent if you have ever seen two of these things push each other around (I built a similer bot using the lego mindstorms NXT system a while ago to vs against my friend in sumo, his robot had rubber on the shell, but not in the middle, and he lost ground every time his shell lifted in the air.)) So a little math (and help from a math teacher) later, and I figured out the required diamiter of the circle, and drew a scale drawing:



 

The bot will have almost ( the walking method requires some blank space, as evedenced by the drawing ) half of the possible area on the ground at any time, and sometimes all of it, which, if covered with an approate high-traction material will give a ridculas amount of grip.

 

The centre circle will be driven by a gearmotor in order to turn the bot, it does not need to be overly powerful, but fast enough to spin the bot at a good enough rate to not let it get ambushed from behind. The walking mechanisim will be driven by a cam system much the same as "clunkers" but with a much smaller cam, the bot does not need to take big steps, nor go fast when pushing, and will be able to get by with a less torquey motor.

 

At the begining of the match, the front plate will fold down giving the bot a nice low profile wedge front, and will also be hinged as in the picture so that if a robot hits the side of my bot instead of dead on the walker will still possibly be able to get under by continuing to rotate. As for opponent detection, just about any method will work, be it mechanical, optical, or sonic.

 

I know, crazy, but I think it might work.....

HOG getting closer...

I worked on the hog drive again last night, I made a gimbal bracket out of lego, hot glue and a servo. Ultra high quality I know, but 1, good enough for a prototype, 2, I was going to use aluminum, but lego is better for rapid prototyping (that, and my hacksaw does not have a blade right now...) 3, lego is still pretty sturdy, and 4, the rest of the frame is going to be lego anyway, so the bracket and base should fit together fine.

Some pics of the bracket:

And a frame around it:

 

The gimbal that you see is for driving, and can move 180 degrees left and right. To steer, it will rase and lower it's rear wheels in tandem, causing a tilt of the whole bot to a "nose up or nose down" attitude. I sort of struggled on how to make the whole bot run, I have seen both a straight up 2 axis gimbal, and one bot that independantly rased or lowered each wheel to drive and steer.  I chose the hybrid method because I wanted to have maximum travel latterally so that the whole hemisphere could be used for driving, and max top speed could be reached, and to do this with a regular gimbal would have been tough. I will not get max travel for steering, but really, I do not need to turn at 150 km/h, that is just a bit excessive... We will see how this system works for a first prototype.

Physics FTW!

This guy's whole channel is awesome...

Minigun complete, now 20,000% better!

Yesterday I finished up my friend's paintball minigun. It now has a continous sparker system, chamber fan, 3-1 chamber  to barrel volume ratio, is very well ballenced, and has the ridculas amount of power I have come to expect from any projectile-hurling device I build.

Chamber fan:

Battery pack:

COMPLETE! shown with end cap, paintballs, and starting fluid.

 



 As to that 20,000% better remark, it was not just idle speculation/exaggeration, before the chamber fan was installed, sometimes the paintballs would only shoot a foot or two, due to incomplete combustion resulting from a less than ideal fuel/air mixture. With normal potato cannons, this is not such a big deal, because the potato generates friction, which keeps it in the barrel long enough for all of the fuel to burn, and thus develop more pressure, enough to hurl it a long way. Paintballs do not have as much friction, so the inital burn will propell them right out of the barrel, with really crappy force. The chamber fan ensures a full burn almost instantaniously, and thus all of the force is developed within a small fraction of a second, resulting with WAY more force. Now those 7-35 paintballs go over 200 feet, thus, 20,000% better.

Progress on the HOG drive

I have been working on the HOG drive a bit recently, I went to the local dollar store and found a few hemispheres that I thought might work:

A rubber ball that could be cut in half, a plastic wind up toy, and a rubber "popper" also shown are the bell from the motor I am using, and an epoxy putty stick from harbour freight tools.

Eventually I settled on using the smiley face popper, because it was already a half-sphere, it was rubberey (good traction) and it had a nice center hole right in the middle. I kneeded up some epoxy putty (REALLY nasty smell...) stuffed it into the popper, and pressed it onto the face of my motor (I had cut down the shaft erlier, and thredded two nuts for more surface area for the putty to grab on.), made sure it was centred, and let it cure for 24 hours, here is the result:

From just eyeballing it, the hemisphere is perfectly centered, and spins fine and true at 8000 RPM. The putty ensures that the ball will not deform at high speeds, and has had no problem holding together at those ridiculesly high speeds. Speaking of high speed, I did some calculations, and the theretical top speed of this thing is going to be somewhere over 150 Km/h, not bad for something so small....

:)

I woke up this morning, and found sitting on the dinner table my prizes from the LMR tic tac toe challenge Naughts and Crosses. I decided I would get a lot more use from a micro magician than I would out of a mini driver, so even tho I came in third, I paid the difference, and got a micro magician. Oddbot (the guy running the challenge) also threw in a pack of female and male jumper wires. When I get some time, I am going to have some fun with my prizes.

On another note, I recently made a paintball cannon for my friend, 4 in ABS combustion chamber, with SEVEN 1/2 in barrels coming out the front, looks like a minigun, mwhahahahah. Anyway, it is not working REALLY well right now, needs a chamber fan, which I have. I cut down a 120mm computer fan untill it had just a bit of clearence between the inside of the chamber, and the tips of the fan blades, that was kinda finincky, spent a while with a calliper and some side cutters to get that working. Now I just need to stop by radio shack and buy a 12v AA battery pack, and it should be complete. These Pictures were taken when I was using a Piezo sparker taken from an old barbecue laying in the dump, it turned out to be unreliable, so I swaped it with an electroninc continous sparking battery opperated sparker.

I also got to go to Spokane WA. on Sunday and pick up some robot building parts, 4 6in lawn mower wheels. The holes in the middle are a bit big to mount directly on chopped up cordless drills, but that will soon be remedied with some metal bushings I will fabricate on the high school's lathe, a cupple of mid size castors, a few small ball castors and a big hunk of epoxy putty (for making a hemisphere for the HOG drive I will make eventually) rounded out the purchase.I love Harbour Freight Tools :)

HOG drive system

This is amazing. When I get some time and find an appropriate hemisphere, I am SOOOOO building one of these. hemispherical omnidirectional gimbaled wheel robot

First One!

Ahhhh, the inaugural post: This blog was started because I thought it would be cool if I had a place other than Facebook and Lets Make Robots to post stuff that I thought was interesting, as well as things not particulary suited to either of those sites. I am going to use this blog somewhat like a journal where I can post  links mainly, but also speculation about a number of things, mainly building robots, potato cannons, and other things that go boom. If anyone reads my thoughts and links, and likes them, that will be awesome, but mainly this site shall be what I would scribble in a journal, possibly gramaticly incorrect, with ocational bad spelling, and quite possibly rants/ramblings, but a good thing to look back on when I am old, and wonder what I did with my time.