Finished the Leave Me ALONE! box

For those who may not know yet, the "Leave Me ALONE!" box is like a "most useless machine" found everywhere... only angrier. It builds up a bit of rage, then turns itself off.This started as an electronics self test to see if I could make an electronics circuit from scratch that could do what I wanted it to do: slowly build up the speed and power of a vibrating pager motor in a building ramp up of "rage", and then activate the arm to cycle the whole machine back off, and put the arm away.

It took a lot of on the breadboard experimenting to get it to work just right. Turns out it takes 3 transistors and a voltage trigger to allow all of the different things to happen. Here is the final schematic:



So you see, now the switch does not directly power the arm motor (far right).To the left is the vibrating motor controls, to the right is the relay arm control, and in the center is the heart of it all: a Big 'ol resistor capacitor RC "thing", that does all of the slowly building up voltages that the rest of the circuits works off of.

 

 

I learned a lot about RC style systems, mostly from a ration of failures in trying to get this to work. See; the resistor slows the charge up of the capacitor (to about 3-5 seconds), meaning that that 4 way intersection in the center will go from 0 to 9 volts in a slow climb. At first, I just tried to have the vibrating motor powered directly at that intersection- it didn't work; the motor was a "path of least resistance" for the power to escape through after passing the resistor. similarly, the intersection would not turn on the relay at around 5v as I planned, because its coil acted the same way as the coil in the motor... so a RC wont ramp up a charge with a 'load' present, and in the end, Neither will do anything. Check! If I had gone to some electronics class or something, I might have been told that at some point... and not known what it meant, exactly. BUT with this practical experience, now I get it!

 

So both the vibrator motor and the relay needed a "buffer" in between. Like a transistor base. The rising voltage will turn on a transistor more and more as it climbs, meaning the thing the transistor is powering (from another route of power)- so, in dumbdum terms: the RC intersection cannot power a thing directly, but can power a knob to adjust the power.

 

The vibrator motor worked with the intersection powering the base of a single NPN.. but the motor peter'ed out (poor Peter.. what did he ever do to get that term named after him?!) at around 4v.. oscillating the circuit.. like the transistor was "floored" already, and couldn't push any more power. So I doubled it up- a "darlington transistor pair" apparently- two NPN's stacked up. At first I thought they would both just drive the motor "in parallel", but apparently this "in series" arrangement works better- not sure why if the first NPN was floored in the first place...? But anyway, 2 NPNs and the motor will power itself right up to 9v and self destruction... if need be.

 

That's where the relay comes in. I had to add a special little hard to find chip: a 1381U voltage trigger (salvaged from some solar engine parts I bought- the U was unusable for those, as it triggers around 4.5v) to keep the NPN from just turning on the relay as soon as possible (which turned out to be MUCH too soon!) So now, with the voltage trigger waiting until it reaches its trigger levels before enabling the NPN, the vibrating motor gets more time to ramp up to a really alarming level. The diode was a little trick I learned to stall the trigger even longer; as the diode "keeps" about .7v as power goes through it, meaning the voltage reaching the trigger is lower than the actual voltage in the capacitor: an extra little delay.

 

I drew this sketch AFTER I had moved this here and there all over the breadboard to get it right, so lets look at the breadboard, wired to control the box externally:

What you see is the relay, the NPN by the relay, and the trigger in the foreground, powering the NPN. The Black and Red jumpers leading to the box went to the motor, the red and green in the background came from the battery/switch. The RC and vibrating motor NPNs are tucked under the Cap (built up previously), and the pager motor is the white blob tucked behind.  Lets see if it works!

 

Looks good from here! (the diode was missing, so the shutoff is rather quick at this stage)

 

Well, with that all said, all that's left to talk about is the neat little arrangement of the relay and motor wiring. You may note that there is no polarity reversing taps, nor a back stop switch to pull the arm back.. yet it pulls back anyway! This is where I start getting DEEP:

 

Its all about Back EMF. Or, more specifically, "Motor Kickback". As a motor is spun, it is also generating its own little power, because the coils are spinning near a magnet. This is the Back EMF (electromagnetic force) that is normally found in all running motors. If the power to the motor is suddenly severed, the Back EMF, which was generating power in the opposite polarity discharges as the motor coasts to a stop. Motor Kickback is a BAD thing in normal electrical engineering (causing belts and such to snap, or motors to lurch in their mounts with the violence), and is usually eliminated with a shunting diode to let the back emf drain away to ground (its just a reversed spike of power that lasts only a moment), found as a diode reverse wired between the motor leads.

 

So Motor Kickback = BAD. Unless you want the motor to kickback! And that's what the motor does in my Leave me ALONE! box. This is why the relay uses both contacts to connect and sever both the ground and the power of the motor simultaneously; with both wires suddenly disconnected, the back EMF has no where to go.. but to drive the motor backwards for as long as it lasts. Which turns out to be just enough! I learned all about this in some other experimental research I was doing, involving scavenging back EMF for usable power... but that's for another time. Whew! {/break DeepMoment;}

 

So, how to pack all of this circuitry in this little 4" x 6" box? printed circuit board? Psh! the Junkbots book taught me about "freeforming" components together.. and I really LIKE the way it looks!

 

So, there it is: all the stuff that was on the breadboard. just SEEING that makes me go "oh, cooool!". If it was going to essentially be the brains of this little box, it might as well look like some brains.. robot brains, of course!

Go ahead! zoom in on the intricate interweavings of all those prongs, each doing its own little thing. To the left is the original RC/vibrating motor driver, in the middle is the newer Trigger/NPN driver for the relay, and the relay itself. The little bits of salvaged wire insulation over some of the prongs helped me remember which ones were switched power and ground. but in the end, I thinks its a bit of a work of art, if I do say so myself.

It was Freeformed into this particular shape to sit neatly in an open spot within the box, as seen here. And thats the neat thing about freeforming: no way a printed circuitboard would fit in there! Plus, it leaves all the stuff inside out of sight from the peeking door, AND leaves me more room for more goodies if I decide to add them later.

All that was left was to wire the power and the two motors in... hmm looks Like I've reached the end of my photo uploads for one post. To be continued!

 

 

 

IR Photoelectronics Learning

You remember the robot Eye I made earlier, right? This was after figuring out how a photo resistor works- varying the resistance it provides to a circuit, and, if balanced against another resistor going to ground, creates a variable voltage divider, meaning that the point in between the resistors will have varying voltage depending on the light hitting the Eye- making the Eye a simple and direct motor controller to make a "photovore" that chases a flashlight around.

Anyway, there are several other types of light sensing devices, and since I wanted to learn robotics and electronics, light sensors seem to be a very important thing to learn about.

After salvaging some photodiodes from an old mouse (the kind with a track ball in the bottom), and other photoelectronics I could recognize in other various old electronics (old TV remotes were an obvious choice), and buying some from radio shack now and then over the months, I now have a rather full assortment of gizmo's.. which I never really figured out how to work.

I followed instructions in the Junkbots book (the book that let me know where to find free goodies in "broken" stuff lying in closets and garages everywhere), I had made a "headbot" that spins in place following a light around, using some exotic "bicore" method that made the pulses of the motor going left-right-left vary according to the light hitting the two "eyes". Pretty cool, and worked just fine.. but I had no real idea how it worked. Not really.

So, tonight I dumped the photoelectronics drawer of my little tackle box shelves, and got to work... getting them to work. heh. I noticed that most of the parts were IR (infrared), so, obviously I needed an IR LED to trigger the sensors, right? I tried a TV remote, but I guess the pulses were very rapid or something, nothing seemed to work, so the first step was to build my very first IR remote control, to test these things and see how to make them work.

And here it is, in all its scratch built, "still trying to look cool" glory. I read on the data card for the IRLED's that the voltage to put to them was "1.7v MAX", so a single AA would do just fine. A momentary push button meant I now had my very own IR flashlight... that I couldn't see any light coming out of...

 



...but my camera could see it! Turns out that digital cameras use some kind of CCD light sensor to see and record the image, and this CCD was able to see slightly beyond Human visual spectrum... obviously! This rather bright LED was completely dark as I shot this pic.. Pretty neat!

 

So, with that done, I got to making a breadboard thing that I could aim the IRLED at to make it do something. So, I set up the board with a 5v relay, wired to show a red LED when it was off, and a green one when it got turned on. It was going to get turned on by the photo diode I chose getting hit by IR light.

 

It didn't work, all by itself. You can see the faint purple of the IRLED coming from the light, and bouncing off of the detector I was using, but the relay wasn't energizing. THIS was the "problems" I was dealing with previously in ever trying to put these neat little sensors to work. But today, I vowed to dig in and tinker with it!

I tried having the power the photo diode let through when light hit it power the base of an NPN transistor. Still nothing. Then I got my meters out. With the 6 volts coming from the blue power supply, and the .7 or so Voltage drop expected from the diode, there should be enough to energize the 5v relay, yet not enough was "getting through". In this picture, you can see that the power the diode is letting through is 3.5v or so, so its already about as high as it can go, but the transistor wasn't "turning on enough" to let the relay click on.





So I began thinking... maybe the relay is too power hungry for the diode or transistor to energize it? I knew the transistor was strong enough, as it had done it before on previous tests with other things, so I knew it was the photo diode not giving enough "oomph" as it were.

 

If the diode was doing all it could do, then the problem was to make it do what >>I<< wanted it to do, by somehow taking the power it was leaking though, and have it be enough to turn on the relay. So, I got a bit unoriginal, and had the diode enable the first transistor, which would enable a second transistor, hopefully making that small change at the beginning bigger and bigger each time I used the transistor to "amplify" the "signal" (Junkbots book taught me that a little "push" at the base means a BIG push through the transistor:: amplify)

 

So, with it all rewired, with a double chain of transistors, I wired up my meter to the final power output of the last transistor, leading off to the relay, far right. This pic shows, even with the ambient desk light, the feeble push from the photo diode was already resulting in 3v waiting at the relay. With more direct IR light hitting it, it should easily trip the relay on now.

 

 

Same light as before, but now with the IRLED adding to the punch, Success! I will admit to a little giggle of delight seeing that green light come on (and almost blow out with too much voltage going through it!!). Weird thing is, the voltage at the meter probe didn't really change much.. but the relay clicked... hrmm. Current maybe?

So far I have only been using variances in voltage to make transistors do things, and thought that the transistors let out more voltage as well.. but now think there may be more going on in there than that. Oh well, that's some learnin' for another time. Now its time to show off!

It may not look like much, but I love that it is all home made, self taught, and actually working! Not shown, but what I did later was add even more transistors the the amplify chain, to see if it would increase the actual range of the sensor's "sight" beyond the roughly 2 foot range it shows above. YUP! each transistor seems to add about a foot! This particular IR sensor is the best I played around with so far- its "view" being all around, as opposed to the other types that had to be a dead on hit with the light to do anything.

 

So this is another Queue card sketch on my file, and another gizmo I'm going to take off the breadboard and make into a purpose built device: "a wheeled Robot tester"; something I can just stick to the motors of a chassis/toy/home built Frankenstein creation, or whatever, put it on the ground, and use my remote to see if the motors are going the right way, the wheels are straight, if it pulls to the left or not, etc.



LEAVE ME ALONE BOX- Vibration add on project.

I really love Instamorph! The stuff is just amazingly useful, and has an additional feature I plan on using from now on, now that I have discovered it: its "refusal" to bond putty state IM against cooled plastic state IM! Why is this cool?! Well, let me show you:

Here is the new vibrator install. It is placed center line, on the heavy end of the box- to make the mass of the box jitter around more (in theory). To the left of the motor is a big new section of IM, thats just a holding frame for the 9V battery, seen socketed in it. I figured this was needed due to the violent vibrations the box would now undergo, plus, the battery kept slipping loose anyway. Added bonus, my thumbprints are now a part of the box for posterity!

 I was originally planning on stuffing the large Cap in the square void left available, but found the vibrator motor fit just fine. So, I got a big glob of Instamorph all warm and clear and playdough-like, and squished the motor into it, then squished the still malleable putty (now more like modeling clay consistency as it cools) into that hole. Since the warm newly installed glob was warm, yet the white stuff to either side of were cold, they didn't interact with each other. Why is this cool?

Because if you notice, the bottom picture glob around the vibrator is already molded to fit in that socket, and YES, it is still removable! Notice the grooves on the bottom, that match the bump lines at the rear of the box. That means this motor is now socketed into a custom molded plug, to fit snugly in its place, yet still be removable! Don't believe me? well, watch:

Its a nice solid click, due to the shape of the plug and socket, when it clicks in, it holds it solidly in place (notice that when trying to remove it again it picked up the whole box). no glue, screws, etc required! how many other mounting methods can claim the same features?! NONE! this stuff is future technology material at its best.

After mounting the motor, and seeing that nothing more was needed to secure it inside the box, it was time to permanently wire the little RC engine that would drive it.




I was trying to go for compact and small, and wound up getting Super Cool looking as well! Bonus! Like my 1wing Solar engine, all of the electronic components fit between the Capacitor prongs, so if I can find room for the Cap, all that's left is to wire the additional wires up.

 

I cant decide if it looks High Tech? or Vacuum Tube Retro? Regardless, its super neat looking (IMHO), and I get a little beam of pride knowing no circuit board was required.

With the intricacies all done, it was now time to test it! lets set it up, place the camera, and see what happens when I (electrician term) "Turn on the Juice, and see what shakes loose!"

 

Yup! I'd say its working OK. and there seems to be enough power- electrical, transistor supplied, motive mass, whichever power you may have thought I was talking about!



PAGER VIBRATOR RAMP UP CIRCUIT

Success! After maybe 5-6 different tries, I have a circuit that works the way I wanted it to!

This is a big achievement for me, as this is the first time had an idea of what I wanted to do first, then successfully designed a series of electronic components that would make it do it correctly! Up to this point, I was either following circuit drawings, or mimicking other circuits, like the solar engines.

This also taught me some more details about capacitors. I already knew how to trickle charge a large Cap up in voltage slowly, either with a trickle coming from a solar cell, or through a high ohm resistor... BUT I never had any practical idea of how to USE that, other than to voltage trigger it to dump it through a motor... making the cap merely a second hand battery.

Now, I know how to make it a timer as well! This is an RC style electronics trick, which most electronics guys would already know about, but I learned it the hard way... as RC to me meant "Radio Controlled" :)

Anyway, here's the circuit, drawn on an index card and definitely going into my "don't forget this trick!" index card box.

So, it took me a few tries; The Cap here, the Cap there, across the motor leads, etc etc.. and it never worked. The Cap wouldn't charge up if there was a motor there to hog all the power, apparently. So, I eventually tried an NPN Transistor between the Cap and motor, hoping that the Base wouldn't "hog" the power from the Cap, and that Base, as it rose in voltage along with the capacitor, would "throttle" the power waiting at the transistor Collector (not sure on the terms yet). Turns out, that was the trick! The capacitor was now "separated" from the motor, the motor getting its power from the transistor. Simple. Sorta. The transistor seemed to peter out with the motor around 5v, and there was 9v there.. so maybe I had reached the limit of what that tiny transistor could "throttle".

SO... hearing about this trick called a "darlington transistor pair", where you simply double up the transistors to get them to supply more working power. THAT was the final problem solved!

 

So, right now that resistor is 1k ohm.. and the ramp up of the pager motor is pretty quick... oh, wait, I didn't show the video of that yet!



Heh.. you cant see it, but the soldering iron resting in those mechanical fingers was vibrated almost out of its holder! Wow that vibrator is strong (when forced with much more power than it was ever designed to take.. hehe). Its out of focus, but I got the gauge in the background showing the voltage rising in the capacitor... It peters out around 7v.. meaning the other 2 is probably what the transistor pair is "stealing" but anyway, it perfectly meets the power requirements to energize the 5v relay after a few seconds delay-  that I plan on adding to my LeaveMeAlone box to give it more "activity"

As I was saying, the resistor causing the delay is 1k Ohm, which is a little too fast I think, but when I tried a 10k ohm, it took too long. So I'm guessing 5k Ohm or so will let the box sit inert for maybe 3 seconds before the first rumblings... then its On like Donkey Kong!! as they say... at least as those as old as I am used to say. heh.

So that's it for today. learning stuff. taking notes. almost vibrating a hot soldering iron into my lap. The usual.

THE MOST USELESS MACHINE

I call mine the "Leave Me ALONE" box, because of what it does, and also because it knows what the rest of the world calls it. Basically, this is a simple device that will make you smile, simply because its only purpose is to turn itself back off if anyone hits the switch.

I got the Idea from Instructables, MakeMagazine, Solarbotics and YouTube stories/ads/videos about it. Its really sort of a "Meme"- like a Viral Idea that spreads like a Virus everywhere rapidly, as in all the articles listed above.

It is a really simple thing, both to build and to wire, yet it behaves like there is more in there going on than there actually is. All that's inside is a double pole, double throw switch, a motor, and a push button switch than can be wired Normally Closed.

Most of the Useless Machines you see online are rather big.. like cigar box sized.. which didn't appeal to me very much. I figured I could make one out of a little radio shack Project box, with a micro DPDT switch, and a mini geared motor I got from solarbotics.

The hardest part was cutting the door away with a hacksaw... carefully slicing a section of the top off, yet leaving it intact enough to replace and hinge with some ubiquitous HotGlue. It makes a really nice spring loaded hinge- that keeps the door flap closed and slammed shut. No springs/screws required!

Seen here painted Silver... I don't know why, to match the painted writing in the channels made with a hot soldering iron (used) tip on the top I guess.

 

After getting it all built and wired up, I was surprised to find this box.. roughly the size of a 5 x 8" index card, had plenty of room inside still!

 



Hrmm Its a little hard to see, but lets try to give a Tour: The 9Volt battery is the 9 volt battery ( :P ), the red thing is the underside of the DPDT switch, the big white Square blob is the mini "Geared Motor"- a motor with a built in gearbox for more torque, the blinding white arm thing is the arm, made of that Instamorph stuff, and hiding under the axle of the arm, is the black contact switch. The paperclip coming off of the right of the arm is what hits the contact switch, and what can be easily bent to adjust the stop portion just right.



If you look closely in the top right corner, you'll see another white blob... that's some more instamorph, using that corners screw mounting posts as a "grip", and wrapping around the back end of the motor case of the gear motor to make... an instant BRACKET. MAN that stuff is handy.. I don't know HOW I lived without it. I guess I would have hot glued it before.

 

So there it is, the silly Leave me ALONE box. I brought it to work, left it on my desk, and everyone couldn't resist but to NOT leave it alone. They all loved it. Oh! I almost forgot the other goofy detail. Notice how all the internals are off to the side, not visible from the door, well, since I knew everyone was going to look inside and not see anything. I figured Id give anyone curious something to look at:

 

 

With all that extra room inside, I feel tempted to add some more "things it does" to it. One of the first ones will be a hidden on/off switch- sometimes it chatters a bit like a ticking time bomb if it gets slammed around a bit, and the arm starts bouncing on the contact switch sping.

 

Other ideas are:

- A vibrating pager motor wired so that when the switch is in the "left alone" position, but the door gets opened (tilt switch on its underside?) the box will vibrate angrily!!  :) (hmm but then I would have to make the box more drop-proof)

 

- A Large cap acting as a time delay, and ramp up for when the switch is engaged- the switch wont directly move the motor, but rather start to ramp up power in the Cap- slowed by a resistor to take a bit of time, the rising power making the pager motor vibrate more and more violently as it gets up to about 5v: the voltage to make the mini relay inside energize- initiating the whole arm thing- rather than the Switch. (this will take some experimenting, learning how to make a capacitor charge up, and at the same time drive the motor for the vibrator under the varying voltage levels).. sort of a "b.b.b.bb.bb.bbbbbbBBBBBBBRRRRRRRRWOOOOOAAAAAOOOOOWWW!!!!*click!*-arm smacks switch, arm retracts, everything stops. vibrations slow down and stop (as CAP drains away the remainder energy)

 

-toothbrush heads chopped off, and holes hut into metal base plate so the bristles stick out on each side of the base as feet- one angled one way, the other the opposite way. IF its not too heavy, as the vibrating motor gets going, the box should spin in place as a "bristlebot" on whatever its sitting on! Placing the weight of the vibrator will be key to this one, but its just a dream at this point.

 

 

So you see, its these ideas that keep me interested in continuing to tinker- if I didn't have these crazy ideas I wanted to try, I wouldn't be quite so mad scientist enthusiastic about it all!!

 

I'm going to go work on that "getting more violent" vibrator circuit. Be back soon with results, if any.



ELECTRONICS: Self taught beginnings.

I admit that the spinners I had built off of the solar engine instructions in the Junkbots... book were built off of instructions, and I really had little Idea of even how the solar engines worked at that point. so, I got a bit serious on discovering things on my own, so that I would know about them without trying to remember lessons learned by rote, or comprehend the paragraphs I just read on things I didnt fully understand yet- that was why I wanted hands-on personal experience.

So, where to begin? Transistors. I knew there were two basic types. NPN and PNP, each with varying performances and attributes, that could be looked up on datasheets online. But I had no need for trivia. I knew most things I build would be low voltage, trickle charged, or running off of a 9volt at most.

So, I set up my little power supply, set it to 3V, and placed an NPN transistor in the center, and put 3 jumper wires inline with the 3 rows the prongs were stuck into. I kind of figured that N stood for Negative, and P for Positive, so I tried putting + to the P part (middle pin), Then an LED to one pin to power, to ground, then the other side, until I got to a point where the darn thing switched the LED on and off with me pulling the middle pin out. I eventually figured out that the two side pins were basically like NO (Normally open) contacts on a relay (which I understood as an electrician), with the middle pin being the "coil". With that figured out I now knew that transistors were tiny little switches.

This is a re creation of my eventual "Eureka!" moment, of getting the transistor(lost between the jumper prongs) to "do its thing"
















Doing a little more "exploring and trying everything" I found out that the NPN transistor didnt really matter which way the current flowed through the ends (collector and base), and it was basically a "conductor". What was odd in my "try everything" was that with power to the base, and either side having the LED, the light would still come on... without anything on the other prong. I didnt know what to do with this little tidbit of knowledge (still cant think of any reason to), but the point is that now I DO know it, and its a part of my experience, not just something I read. So its with me now.

Next I looked into the "amplification" factor of transistors; how a weak change in the Base makes a BIG change in the mainline power flowing through the ends. Trying to keep robotics in mind, I used a photoresistor to drive a small motor at different speeds with different light levels. It didnt work very well by itself. The resistance was just too high for the 5V to push through the resistor AND drive the little motor. So I tried the photresistor as a variable current into the base of an NPN, to see if this "amplification" thing would do what I thought. It didnt. The resistor varied the current to the base, but this only resulted in an on, or off state to the motor, which did in fact drive now, just all the time, using the transistor as a pathway for the power.

It was time to do some thinking. I had read up in a "beginning electronics" book about "voltage dividers" and knew a bit about the ohms law theory of it all (electrician, remember); about how the voltage drops were divided up evenly along the different loads in a series circuit.  This gave me a little lightbulb moment: "maybe I dont adjust the current to the base, but rather the VOLTAGE!" I eagerly put the photoresistor from power to base, like it was before, only now added a 1k ohm resistor from that base to ground.. this should vary the voltage to the base as the resistance of the photresistor changes between its 10k ohm and 2k ohm range. It worked GREAT!

After making a system that worked, I then went on to make something to keep my interest going: I made a Robot Eye.

Point of note: it was built to look like an eye- with "neuron" blob solder joints, to tangled optic nerve wires- on PURPOSE. :) It is really as simple as a photoresistor, a NPN transistor, a 1k ohm resistor, and 3 color coded wires: Red= + voltage, Green= Ground, Black= Motor power lead.







Having a purpose to strive for made all the puzzling out less tedious. I now had an Eye that could vary the speed of a wheeled motor. Cross connect the eyes to the opposite motors, and the eye facing the light would make the opposite wheel go faster, making it follow/chase a light around.  THAT is the far off goal that keeps me at it!

Oh, how about a video of the Eye driving a wheel?

So yeah, progress was made rather quickly with simple level electronics aimed at doing something "neat". That wheel/geared motor, by the way, used to be a TrekBot.
http://www.mydeskpets.com/trekbot/
These are found at RadioShack, and are pretty much mass produced BEAM bots all in themselves. I bought a couple of these, played with them the prerequisite amount, then promptly tore them apart for parts, and a rather cool hubless wheel design.

I asked the People at DeskPets if it was ok to "hack" their toys, in order to make other things with them, and that I was intereted in making some of them into BEAM photovores instead of remote control. They replied that it was perfectly fine, they love BEAM hacking too, and even gave me the pinouts of the tiny chip inside that drives the H-bridges to fwd or reverse the wheels!!! That was above and beyond what I expected, those guys are awesome! and make some pretty cool gizmos, as well.

The SkitterBot, TrekBot, and TankBot are my favorite. I have bought (and frankenstein monster'ed) many of them over the months.

SPINNERS.

This is a good representation of my slow but steady improvement in making basic BEAM bots that dont do too much... just spin.

Lets start off with my old Symet, built from the Book instructions (Junkbots, etc). WOW what a klunker!!:

That is a 1/4" grid graphpaper, so you can see just how HUGE-UH this thing was. its actually kinda silly looking nowadays. The thing was, I couldnt find any low voltage 4700 Caps (like the one in the transistor testor) at the time, and used all I could get: 10volt ones. I know now they are simply MUCH too heavy to make a solar powered thing that actually uh.. does anything.

Above it is the qeue cards I started making for myself, little reminders on circuit designs of stuff I may come back to later and need a quick reminder on what goes where.

The motor is a pancake motor I got from a Cassette walkman from the 80s/90s- I did what the Book reccomended, and asked my coworokers if they had any old walkmen tapedecks laying around that they didnt want anymore.. and BOY did they start coming in! I got like 5 of them to tear apart for the rather excellent motors to be had within (this one ran on 1.7 volts, drawing only 35mA- with some pretty good torque, by way of example). The Solar cell is one of several I mail ordered from Solarbotics. These poor cells are having a hard living, but they are resin encased, so, except for the printed circuitry tabs tearing away, theyre pretty much indestructable.  BTW: that little cell, measuring 37x33mm.. is a 6 volt, ~50ma (!!!)

This side view shows how it is supposed to work- the pulley (smeared in dried school glue for better grip) sits at an angle, propped up on the edge of the Capacitors, just barely not dragging the case on the ground. What this does is when the motor turns on, say, clockwise, like this the symet will slide towards me, until it runs into something, tips anoter way, and now the turning wheel will send it skitting in some other direction. Pretty cool, but all my klunky old thing can do is twitch. (and UGH the lousy cold welds on the casing!!!)

But anyway, that is the first I ever built.

Next is one from a failed experiment. I call it "1Wing":

This one has the smaller 4700 cap, and a different solar engine than the first Symet (that was a flashing LED solar engine). This one is a fancier 1381c solar engine, using a special voltage trigger chip- one of those transistor looking things crammed in between the capacitor prongs. That little black blob with the red diode is indeed the entire engine.

This is "1Wing" because it was supposed to be one side of a pair- in an attempt to make a Photovore that didnt actually have any eyes, yet still tracked towards a light due to the solar engine getting the most light firing more often, turning the bot to it (by running the opposite side motor). The blind photovore failed as a prototype, because for some reason one wing worked extra well, the other maybe 1/3 as well... meaning it didnt do what I wanted it to do. bummer.

 

But I kept the good solar engine, put the motor on its own wing, and made it a sort of spinner. This was my forst working solar engine that actually... worked.

 The cell is actually one of the big ones, cut down the center, where the two arrays of cells inside the resin are separated. I realized that the 6V was really just 2 3v ones wired in series, so that actually meant I could make 2 cells out of one!

 

Heres a rather boring video of it doing something... but what makes me grin is that "look Ma, no batteries!", and it really is running off of the desklight.

Yeah.. I warned you it wasnt very exciting, dont worry, the rest are much more active, as I DID get better at making these things.

 

 

So what was next... OH my "little engine that could":

Remember that the grid is 1/4" squares, so thats why its called "little". It uses another cell from Solarbotics, a 22x24mm one, (3v, ~20mA), a tiny pager vibrator motor, and uses the solar engine printed on the back of the card, seen in the next pic.

Kinda messy with the Hot Glue holding it all together. But you may wonder what the point was. This little engine was the end result of me tweaking this and that to take this cell, that Cap, that motor, and make the Best Darn Engine I could out of it, squeaking the most performance out of the limited power trickling in from the daylight. I tweaked mostly just the weight of the chassis, the arrangement of the "wheel" (a glob of tacky hotglue), and the timer capacitor (tan thing) that controls how long the voltage trigger stay "triggered". This is a fine line- between either draining the Cap completely and a slow recharge of the Cap, or a too rapid drain, getting not much motor activity and leaving a full Cap all the time. So you see, even with such few components, something as simple as a timing Cap can make ALL the difference!

 

 

Heres a video showing the best performance I was able to get: the lightest possible setup, the most direct wheel to ground drive, the best "power curve" of pulses:



 Yeah.. pretty Active.. if I do say so myself, running under a 100watt desklight. But why is it the "Little Engine THAT COULD"?

 

Because it could "turn over"!! The charge/discharge cycle, if given enough light, could cycle in between the time it takes for the motor to coast to a stop.. so... it runs continuously!

This is a big deal for me, because its important to know that the cell, with its trickle of current, could NEVER direct drive the motor on its own, directly. But with a Solar engine, and a millisecond short cycletime of pulses, it could in fact do the job!

 

 

Now that just warms my Heart. This little gizmo, about the size of a quarter, would run nonstop everyday until the end of time, or until a breakdown happens (so take THAT Zombie apocalypse! LOL). Maybe I will have it encased in a plexiglass domed display case on my tombstone for all the world to marvel at... too much? ah well, the inner geek in me got carried away.

 

But next lets see what a SERIOUS solar powered spinner can do: This one is bought from Solarbotics, and is called a "Battle Symmet" from an Instructables article(http://www.instructables.com/id/Solar-Powered-Battle-Symet-BEAM-Style/), and comes in a "solder it yourself" kit bag of parts. Lets see... linky:  http://www.solarbotics.com/product/60010/

When I saw this parts list, the somewhat BEAM educated geek in me went OOoooH! over some of the parts: a coreless induction pager motor, a .33F (thats like 330,000uf) SuperCapacitor, some wheels that fit on paperclips, etc... I went a little overboard, and bought like 6 of them.

So, if you clicked the linkys above, you know what its supposed to basically look like. I modified mine a bit, 1 for looks, and one for performance (of a sort):

 



I think mine looks meaner, more sleek, more well, just geektastic I guess. I built 3 of them, to battle it out in a slighly bowl shaped styrofoam plate, and kept track of which one was the "champion" by either being most active, hammering the other battle bot around more, or even BREAKING the other bot with a nasty tangle. The losers got disassembled for parts for other things, and the winner got some finishing touches, and a permanent place in my "cool stuff" tacklebox.

In addition to the blade "weapons" on the ring (these are the striking edges, afterall), what makes this little demon a bit more custom is the little scratch you see to the left of the motor, in the printed circuit strip along the left side. If you look closely, you can see tiny green wires in an X cross connecting the corners. What this means is that the two 3v cell arrays in the panel are wired in paralell now, no longer series. So instead of a 6v,~40mA, its theoretically a 3v, ~80mA... that doesnt work so well in less than optimal light (that was the drawback, but I figure all battle arenas will be lit... right?)

So, looking back at ol' 1Wing in its sedately pulsed spins around and around... how does one with some serious performance BEAM components do in comparison? The supercap (the blue chrome thing.. TINY for so much power) takes a bit of time to build up a charge... but when the voltage trigger sets it loose... well, lets just watch:

Pretty much awesome.

 

Thats it for my spinner Phase of learning (oh! I made a rear view mirror spinner, in my truck! details on that later.), but now we come to a bit of sad part of this Hobby and Learning experience. After eagerly absorbing all I can on BEAM robotics, technology, tricks, and events, and many many internet searches for more, more MORE... I noticed something unfortunate... most BEAM related websites havent been updated since roughly 2002!! Meaning the world has apparently "lost interest" YahooAnswers on this subject informed me that the age of discreet electronic components was giving way to integrated components, leaving little things like the voltage trigger in its transistor package a thing of the past- consumer elctronics simply dont have them inside anymore. Nor are these things called "cassette tape players" that need high efficiency motors around anymore.

 

So, bummer. My mean little blade hammer Battle has no one to battle. The timed dragrace solaroller I was designing has no events to compete in.  So these Gizmo's are ultimately just for my own personal "giggle factor". But so be it! Giggle, I Shall! and keep on building!

 

After this slightly disheartening discovery, my focus drifted a bit... but to other neat things. Like Arduino. More on that later as well, because that has some great robotics aspects as well.