Robot Building Progress Report


I have been working on a robot "mascot" for The Science Fiction and Beer Channel.  I decided that it should have the slapdash look of the robots that were on Mystery Science Theater 3000.  The robot should be a box robot, just like so many of the robot costumes kids made in the past.  It should  be relatively small, and it should be able to speak on its own and roll around on the floor.  My basic design is as follows. 

robot mascot

I had some left over parts from past projects, so I use a lot of them in the project.  Luckily enough, it'ds the Christmas season, ,and Dollar Tree is selling strings of 10 LED Christmas tree lights for $1.00 each.  I bought several sets.

As I said, I wanted the robot to be at least partially an actual robot.  One solution would be to make the robot body, and have it operated by me.  The robot's voice could be dubbed in, and I could make its speech lights flash with a momentary contact switch.  I could mount the robot on a set of wheels, and pull it around with a fishing line.

That was too simple, and would look cheap, I thought.  My first plan was to have a cell phone inside of the robot, which would play MP3 filers I recorded.  The files would be fed through a circuit I built, which would make LEDs flash in sync with the recording.  I knew a TIP 31 transistor could do the job-- and since I had several of them on hand, that is what I went for.  A design to work with the Dollar Tree LEDs was easy enough to come by.

I had to tear apart the battery housing for the LED lights.  You'll want to snip off the battery lead ends.  Keep the resistor intact.   That is the + part of the circuit.

voice sync lights

I attached this to a radio, and had immediate success.  I had to pull the earphone plug halfway out to both make the LEDs flash and hear the music.  The original circuit worked with a 12v battery.  A standard "heavy duty"  9v battery gets drained rather quickly, I found, so I'll need to either get a 12v battery, or get an adapter so I can use 4 AA cells.  Below is a video of the lights in action.

  The test worked fine with the radio.  I had to turn the radio almost all the way up to get the LEDs to flash.  I did a test run, attaching my cell phone to the voice circuit.  There wasn't enough power coming out of the phone to allow the circuit to work.  So I needed to order a small amplifier and some speakers.  Once I get the amplifier, I will hook it up and give a list of parts needed.

For the robot's voice, I decided to use a program called Audacity to create the basicd robot voice, and then save the sound files to be played back on an MP3 player (in this case, a cell phone).  Audacity is a free program that you can download it here.

To make a robotic voice in Audacity:

Open up Audacity, and use the File menu to select "Open". Navigate to the file you just saved and then open it.

Here's where the real action is! Throughout the following steps you'll need to make sure that the whole audio file is selected by pressing CTRL+A. Here we go!

1) Select the whole audio file. Use CTRL+A (hold down control and press the "A" key)
2) Click on "Effect" in the menu bar, and select "Change Pitch..."
3) Change the pitch -14%, and click OK.
4) In the Effect menu, choose "Echo"
5) Change "Delay time" to .015 and "Decay Factor" to .65. Click OK.
6) Again in the Effect menu, choose "Change Tempo..."
7) Decrease the tempo by 10% (-10.000) and click OK
8) Repeat steps 4 and 5

Now play your robot voice with the green "Play" button toward the top. Isn't it amazing?

Last but not least, click on "File" and then "Export as WAV..." and save it wherever you like.

Special thanks to and in particular geocrasher, for coming up with this.  You can monkey around with the pitch, echo, delay time and tempo controls to individualize your robot voice.

What I do is then convert audio WAV files from Audacity to MP3 files. will do this for small files.  Or you can download Format Factory here and do it yourself.

I also needed some random flashing lights.  All Electronics sells single flasher LEDs which are attached to 9v battery leads.  by wiring them in serial with the Dollar Tree LEDs, I could make a string of flashing LEDs.  By rigging up a second set of lights, I could place them together and the seconds set would make the lights look like they were flashing randomly.  Here is a general idea of what I did.

flashing led circuit

The leads were soldered to the back of the flasher LED.  The 9v battery clip was attached to a standard Dollar Tree 9V battery. 
Below are just some parts I had on hand to decorate the robot.

some robot parts i already had

The arms, claws and shoulders are made out of PVC elbows. a toy called a sound horn, and some plastic forks.  The head dome is the lid from a butterscotch pudding I bought as a pharmacy.  Next to that is a standard VU meter.  Below that are a couple of knobs.  To the lower left: a standard toggle on/off switch.  Lower right: a small flashlight from Dollar Tree, which will be used as the robot's video camera/eye.

For the most part, I want the knobs and so on to actually work, and not be just decoration.  The toggle switch will actually turn on the robot's power.  The VU meter will be wired to the speech circuit (diagram to follow later), and will flip back and forth when the robot speaks.  I have found that the voltage as it is is too much for the VU meter, so I will wire a potentiometer to the circuit, which will lower the voltage and make the VU meter move much more gently.

To make the robot move, I purchased a remote control "stunt car" from Harbor Freight.  Right away, I could see that adapting it to fit on the robot could be a problem: figuring out how to connect it to the bottom of my robot would be difficult at best.  Using the car, i found it had one speed: way too fast.  It's called a stunt car mainly because you can't just drive it normally.  It tends to "pop a wheelie" every time it's used.  Notice that it has a wheel at the top so it doesn't flip over on its back. 

harbor freight stunt car

I'm going to see if I can rig up a couple of potentiometers to the wheels, to slow the whole mechanism down a bit.  For $4.00 more, I could have bought a radio controlled tank from Toys R Us, which would have solved the problem of mounting the robot, as it has a good, flat top.  I might just pull my wallet out and get that.

My original plan was to make an actual box robot: that is, to use an actual cardboard box and mount everything in that.  While the cardboard was easy enough to work with (and free, as I already had the box), it tended to tear easily, and frankly looked like crap. 

I decided to make a box out of 1/4" plywood and 1" x 2" furring strips.  The entire assembly would be butt jointed together.  The 2" x 1" furring strips would be a sort of skeleton inside of the structure, to give it strength.  I built a set of surround sound speakers using this method.

I figured out the measurements in my head-- and guessed wrong.  The side panels fit together perfectly, but the top and bottom panels came up short.  Rather than start over or have new panels cut, I am going to rely on the wood butcher's best friend: plastic wood.  I'll fill in the gaps, and sand the thing smooth.  To paraphrase Pee Wee Herman, it will look like "I meant to do that."  Below is the robot's body, to date.  I will be drilling holes for the knobs and so on, putting the plastic wood on, sanding it and painting it this week.  It's not the best looking box in the world, but structurally, it's sound, and the best part about it is that it's lightweight.

robot box

Here is an image of the revised front panel.  I'll be printing that out on card stock, and rubber cementing it to the front of the robot.  The black area on the upper left is where the speech lights will go.

Fans of movie serials will recognize the speed control panel as the same one worn by Commando Cody to operate his jet pack.  I didn't care much for the Commander Cody serials, but I did like how absurd the jet pack was.  The speed control makes no more sense on a robot than it did for Commando Cody's jet pack.

front p;anel

I have to close this by mentioning that Dollar Tree is a robot builder's best friends.  I found all sorts of doodads to put on my robot to make it look cool.  And I can't forget to mention, yet again, the string of 10 Christmas tree LEDs.  Just try buying 10 LEDs, with a resistor, for that price anywhere else!

Another great Dollar Tree product is Fix-All adhesive.  Some people confuse it with Super Glue, which is mentioned on the label.  This stuff is a great deal like a very popular (and expensive) crafter's glue: E 6000.  It acts the same way when used.  About the only difference is that Fix-All uses a different solvent than E 6000 does.  That's it.  The glues are interchangeable.  I used Fix-All to assemble my robot's arms.

Update: 11/17/2016

Below is a "dry fit" of the robot parts.  Sanding, filling and painting will come later.  The rather crudely drawn rectangle is where the robot's speech lights will go.

science fiction and beer robot mascot

The original plan was to have the access panel be in a door on the back.  Then I realized that was unnecessary work: I'll just attach the top lid with either magnets or Velcro, and access the inside through that.

I am still at an impasse as to how to have the robot move.  I bought a tank from Toys r Us, the
True Heroes Sentinel 1 Radio Control 8 Wheel Battle Tank.  It's a decent toy, but painfully slow.  I put some weight on it to see what it could do.  It stopped moving.  It could never propel my robot's body.  I'm thinking about using the Harbor Freight r/c car to propel my robot.  It certainly has the torque to do the job.   I could slow that car down by simply reducing the voltage to the motors. 

I'll probably teari the tank apart and use its parts to make my robot's arms and camera move.

toys r us battle tank

I looked all over the web for something that could adequately power my TIP31 voice circuit.  I found it in a tiny stereo amplifier, a 10 Watts per channel PAM8610.  The thing is, several manufacturers are making amplifiers based on the PAM8610 chip, which means that there are several ways to wire up the speakers.  I finally found a diagram that was for the unit I bought.  If you decide to buy this amplifier, be sure to check that any wiring diagrams you see for it match the exact amplifier model you bought. 

I am waiting for a 3.5mm to 2.5mm stereo plug adapter to come in, so I can test it.  My original plan was to have the robot complete by Thanksgiving.  It will be mostly done by then, but that one part will delay things.  It's frustrating.

pam8610 specifics

Special thanks to for providing this information. 

Here is the complete circuit diagram for my robot's speech center.  The thought has occurred to me that I could also call my cell phone and make the robot speak directly from my voice.  The speaker is 40mm, 4 ohms, 3 watts.  It sounds appropriately tinny.  It will be mounted on the robot's lid, behind the clear dome.

The toggle switch you see on the front of the robot will be used to turn the robot's speech system on.

There are two flashing light circuits, which are not shown.  The first set of 20 flashing lights will be on the lid of the robot.  The other set of 20 will be in a clear project box inside of the robot.  This will be a plot point in a future episode: it will be called the robot's brain.

robot speech circuit

I must  confess at this point that my knowledge of electronics is minimal.  I can hook up a surround sound system just fine, but when it comes to using a soldering iron, I was until recently the king of the cold solder joints.  I finally found a soldering method that worked for me.  My solder joints aren't pretty, but they do hold now.

One product I have tried is something called Wire Glue; it's also called Liquid Wire.  It's essentially water based paint mixed with graphite.  As frustrating as I found soldering, Wire Glue was ten times worse.  The stuff takes hours to dry, and even when dry it doesn't hold too well. 

Finally, I was tearing apart an old cassette deck that didn't work.  I found a relay inside, which, while I don't have a use for it at the moment, I am sure that I will find something I can use it for.  With 9V applied, the relay pulls itself down.  It's held up by a rather thin spring, so I couldn't put much weight on it.  Maybe my robot needs to have some sort of radar dish that goes up and down when it's excited.  That requires some thought, but I have plenty of time to do that.

Update: 11/29/2016

Robot 4-Q made his official debut on The Science Fiction and Beer Channel.  He was nowhere complete, but I managed to patch him together long enough to make the video.  After that, I had to gut him and rewire him completely.

The song he sings, "Daisy Bell," has a long history among computer fans.

1961: The IBM 7080 computer became the first computer programmed to sing.  The song was "Daisy Bell."

1968: TYhe Hal 9000 computer in the film 2001: A Space Odyssey sang that song.

1975: Steve Dompier programmed the firest ever home computer, the Altair 8800, to play that song for a meeting of the Homebrew Computer Club.  Until that time, the Altair 8800 was little more than a big, expensive, difficult to operate calculator. 

Below are a couple of photos of the insides of 4-Q as he looks today.  People with weak stomachs are advised not to look.

robot lower body

Robot: lower body. The right is the front of the robot.

robot top (head) unit

Robot, top/head unit.  The right is the front of the robot.

I am still lookiong into ways to motorize him, so he can move his arms and roll around.

I decided that since the robot weighed quite a bit anyway, that putting in a couple of good hi fi speakers wouldn't hurt.  That's a 6 inch woofer and a 5 inch horn piezo tweeter in there.

Asd a side note: That PAM 8600 amplifier is a true wonder.  It's truly what they call high fidelity.  It can compete with the best amplifiers out there.  Unfortunately, it doesn't work with the TIP31 circuit.  So now I am in search of a simple amplifier.  Ebay has a rather nice looking stereo amplifier for a car, which would work alongside with my original plan of using a cell phone as an MP3 player.  A stopgap solution would be to buy an old tape recorder and use that.

I decided to redesign the interior circuits.  Gone is the complicated circuit I described above. I decided I wanted two flashing LEDa on the robot too.   The voice sync lights are on a  separate circuit--in fact, the first design I presented.  To get the VU meter to go back and forth, I hooked it up to one of those flashing light LEDs I mentioned earlier. The potentiometer slows down the VU meter' movement.  Without it, it would slam into its right side, making a sound like a metronome. The final design is as follows:

new vu circuit

Notice how neat and precise this schematic looks, as compared to its actual execution above.

By the next update,I should have a video of 4-Q talking, with all of his lights and so on working.  If my bank account holds out, I might have him mobile as well.

I am still looking into what sort of motors to get, as well as what gears to use and so on.  I've been told that buying those r/c cars that kids can ride in is a good solution.  It's a solution all right, but not a cheap one. 

A note of advice: If you're going to take apart r/c cars to use them for a robot, please be advised that the Chinese makers of those cars use very thin, very brittle wire.  The stuff snaps off the circuit boards very easily.  I've taken to putting huge globs of hot melt glue on the boards I use, simply to keep the wires from coming off.  On the plus side, the stuff is very easy to solder.  Just touch a hot soldering iron to it and the solder forms a joint instantly.

One more thing I found is that with every r/c car I have torn apart, most of the screws come off easily.  But there are always at least two screws that seem like they were tightened by machine.  They are almost impossible to get out, unless you bear down on them when unscrewing them.  I've come close to stripping a couple of Phillips screwdrivers.

Update: 12/11/2016

In short order, I burned out three TIP31 transistors, one after the other, in my LED voice sync circuit.  As I was testing the sound system.  I noticed the lights were getting dimmer and dimmer as they flashed.  OK, the original design called for 12 volts, so I used that.  That was a big mistake, as I found out after I went through my remaining stock of TIP31s.  Doing some research, I found some information.  I've ordered some replacement TIP31s, as well as some new parts for the circuit.  Here is a diagram of what I will be building.

   revised tip31 cirxcuit

Looking back, the fuse and toggle switch should have been obvious.  I found out that you need a 1K ohm resistor attached to pin 1 (base) of the TIP31 to keep it from burning out.

I have found what I hope will be the chassis of my robot.  I bought a silver Ferrari GZ racing r c car.  I got it on Amazon for $49.95.  It's got a 12 volt motor, and from the tests I have done it can propel my robot's body with no problem. IMounting my robot to its chassis looks like it will be easy enough.  I'll be building a housing around it to both hide the chassis and to attach it to my robot.

robot chassis

It's a classy looking car, and is very well made.  It's almost a shame to have to take it apart.  Almost.

One thing I did find peculiar: after one day it stopped working.  I took it apart and examined it.  Sure enough, one of the leads came off of the car's power switch.  It was a cold solder joint, and for some reason the wire was just laid on top of the switch when it was soldered.  I always make sure that my physical joints are secure before soldering, but I guess factory workers don't have time for that.  At any event, I re-soldered the joint, and it works fine now.

The car has headlights on when it goes forward, and backup lights when it goes in reverse.  I'll be using those, in the same way.  Then I thought, "Why not have a backup beeper like cars and trucks have?"  Looking up beepers, I found one at the All Electronics website.  It's called a piezo beeper, pulse tone, CAT# SBZ-416, $3.30 each.  I'll wire this in with the backup light LEDs.

The robot's arm motors have been attached.  Since the arms end up a little lower than the robot's body, I'll hold off on attaching them until I get the chassis and chassis covering installed.  The arms and eye/camera are controlled by the same r c board.  Since that board has only two controls, I wired the arms together in series, so that both will move at the same time.

The sound system has been the big problem with this project.  The amplifier I bought doesn't work with the TIP31 lighting circuit.  I went through several ideas, including using a tape recorder and two walkie talkies.  And then I came up with what I think will work.  I will use my cell phone's bluetooth feature to broadcast to a bluetooth speaker inside of the robot.  The speaker part will be removed.  An earphone jack will lead to a Y splitter: one branch will go to the TIP31 circuit, and the other branch will go to that amplifier I bought.  The robot already has a set of speakers inside of him.

I'll have to add the earphone jack to the bluetooth speaker myself.  I googled "bluetooth speaker with an earphone jack," only to find several discussion forums with people asking where they can get a bluetooth speaker with an earphone jack.  It's such an obvious feature that I am surprised that no one has gotten around to making one like that.

At this moment, I will have to use two remote controls to operate my robot: one for his arms and head, and one to propel his body.  Eventually I'll pull them both apart and mount them in a plywood box. 

I'm looking at a completion date around the middle of January 2017.  Provided, of course, that there are no more major mishaps.

Update: 12/16/2016

I attached the arms, and tested the motors.  I had wired the whole thing up in series, with both arms moving at the same time.  Things didn't work too well.  I had been using wire I salvaged from such things as patch cords and so on. Both arms moved rather lethargically.  So I went over everything.  After a few hours, I found that the main problem was that the battery I had been using (a standard 9V battery) was about out of juice. At that point I had taken everything apart several times, as well as rewiring the arms so that they were wired parallel.  With the new battery system (six AA batteries mounted in a battery holder with a 9V clip), they finally worked.  While I was at it, I shortened the arms so they could spin when he wasn't mounted to his chassis.

The arms work almost too well.  They spin around so fast that they make the robot look like a helicopter.  This will be good for comic effect, to show when the robot is excited.  Parts of the arms do fly off from time to time.  That calls for more secure gluing.

I keep thinking of new ways to run the robot's audio.  I had toyed with the idea of using a bluetooth speaker, as I mentioned above.  A new cell phone costs about $10.  I could place that in the robot and broadcast his voice to him on my own cell phone, again via bluetooth.  I found a mini AB amplifier, which should work with my TIP31 circuit.

The robot's eye was a rather  lucky accident on my part.  I found a flashlight at Dollar Tree that looked a lot like a TV camera.  The light wasn't tall enough to see through the dome (which was actually a lid from a butterscotch pudding I bought).  I had a small speaker from a tank r c model I bought.  Sure enough, it was the right size.  I hot glued it onto the gear that moves the eye.  The bottom of the eye was round, so I hot glued a 1/4" nut on the bottom of it.  Then I found out that the speaker's magnet will hold the eye in place perfectly.  This is a great advantage, as I'm always taking the lid off of the robot to work on it.

All along I had used a piece of printed card stock for the robot's front instrument panel.  It looks OK, but it does tend the get torn and wrinkled.  Then it hit me: I'll go to a copy shop and have a transparency made of the panel.  It will be printed in reverse, so the toner will be on the inside, where it can't get scratched.  Under the transparency I will have either metallic wrapping paper or mylar.  The instrument panel will look like it's made of metal.  I'm still trying to decide on whether to make the metal's color silver or gold.  The paper/mylar and transparency assembly will be attached to the robot with small screws, which will make it actually make it look a bit more authentic.

I still have a lot to do, but at least the end is in sight now.  Looking back, I could have made things simpler on myself, making 4-Q as a puppet like Tom Servo.  Something compelled me to make him a bit more like a robot.  He will be sort of a combination of a robot and a remote controlled car.  Of course, if you count the machines in the TV show "Battlebots" as robots, then 4-Q is a sho' nuff robot.

As he is right now, 4-Q has the parts from three r c cars in him, a 6" woofer, a 5" tweeter, and a whole lot of other components.  I've had a lot of false starts with him.  If you look carefully at the progress report video, you can see inside of him wires leading to nowhere: oftentimes I'd put something in him that ended up not working, so I'd tear it out, leaving the wires behind. 

One thing I have learned: hot glue is a great way of insulating wires and holding them in place.  Hot glue should only be applied when the project is finished, and not before.  It's easier to just leave the old glued in wires in there than to try to pull them out.

I've got a decent set of battle scars from putting this robot together.  I don't think you can be a proper robot maker without some soldering iron or hot glue burns.  And if you're a robot builder and suddenly find your fingers or thumbs bending over and hurting like all get out, and having to bend them back and hold them in place to stop the pain-- Smile!  You've got carpal tunnel. 

Take a look at the video below.  Let me know if you think it was worth it.

Update: 12/31/2016
I found a meter at an electronics supply catalog.  The next day, I went to Dollar Tree, and I found a gum machine that would make a passable robot's head.  Lord help me, I'm going to build another robot.I've wired up the gumball/robot head with some flasher LEDs and a TIP3 synchronization circuit.  Here is what I have done so far.

robot head and body meter

You can see the flasher bulbs and the transistor for the TIP31 circuit.

And here is what the robot will look like

big brother robot

The storyline is that 4-Q hears that he has an older brother, which I took apart.  He keeps bugging me to put him back together.  He doesn't listen to me when I say the robot is evil: he wants a big bother.  Humor ensues when 4-Q discovers his brother is the boring kind of evil.

That meter I found is quite sensitive, and has a large (over 6" across) face.  I reworked some of the circuits I have in 4-Q, and tested them out on the meter.  They worked fine.  Below are four dirt simple circuits that I plan on having in the Big Brother bot.  A SP4T switch will be used to switch between the circuits.

tip31 circuit      metronome

ufo detector      ohmmeter

The UFO detector is a very simple gaussmeter.  You can get 7805 transistors and hall effect devices (SIP) from several eBay dealers.  It can also detect ghosts, provided the ghosts are magnetic.

Work on 4-Q is going ahead.  I discovered the reason his arms motors stopped working: the motors were defective.  The receiver in his head section works fine.  So the old motors have been torn out, and a new pair-- a pair with reduction gearboxes-- will be installed.

4-Q's chassis should be simple enough to mount.  I think that using standard .25" x 4" carriage bolts with nuts would hold 4-Q's support platform well enough.  4-Q himself will be held to the platform with Velcro.  If the script doesn't require him to move, such as when we're discussing a movie, his main body section only will be used.

Just for fun, Robot 4-Q has his own email address now.  Fans wishing to write to robot 4-Q can click on the link below, or email him at  He can be strident, and frequently goes on rants about robot civil rights, Asimov's three laws of robotics, and how vastly unfair robot life is.

email robot 4-q


I won't go into all the details, but I experimented around with several ways to get that darned TIP31 circuit to work.  I found out that if the level of the recording is loud enough, I can plug my cell phone directly into the TIP31 and have the LEDs flash.  My cell phone, an Android One Touch, can use apps.  There is a free app that changes your voice.  I tried "deep voice" and bingo!  The perfect voice for 4-Q.  This app has a text to speech option.  It gives 4-Q the proper robotic sound.

But my previous work was not wasted effort: I have a 20 watt amplifier installed, which I can use to adjust the playback volume.  Goodgoshamighty, but this is a big breakthrough.

The motors on 4-Q's arms never did work right.  One day they just gave up the ghost.  So I went to  eBay and typed in "6v motor reduction gearbox," and found a motor that would work.  I got two of them.  The robot's arms will still be moving at the same time, but they will be moving at 8 RPM, which is quite a bit safer than with the old motors.


...And I spoke too soon.  The circuit stopped working with my phone.  So I went the rounds, testing everything.  I found that by pulling out the earphone plug partially that it would work.  I have an android phone.  I Googled "android phone earphone jack defective," and found that just about all android phones have that problem.

In other words, the system would work fine with a phone that had a working earphone jack.

And so I experimented around.  I could have just bought another cell phone, or a bluetooth speaker, and gone forward.  I worked with what I had, and came up with a workable solution.  It's going to sound strange, but it works, and it didn't cost me anything.

I had tried the PAM 8610 amplifier with my cell phone and the LEDs stayed on, as long as the amplifier was connected.  By messing around with connections, I knew that putting a mono plug adapter in the cell phone would make it work with th TIP31 circuit, until the earphone jack decided it didn't want to play nice.

The first thing I did was put in the mono jack adapter.  I connected a second TIP31 circuit I had to one of the speakers inside of the robot.  Aha!  The lights flash perfectly in time with the sound, flashing brighter as I turned up the volume.

I tried connecting the second TIP31 circuit directly to the amplifier.  That didn't work.  For some reason, it only works when the circuit is attached to one of the interior speakers.  OK, I can live with that.

After a half hour of redoing wires and soldering bits and pieces together, again, success.  Mind you the lights are still on all the time when the amp is on, but they also flash in time with the sound.

I realize that a different cell phone would also solve the problem.  And that is something I will pursue.  But for now, I'm happy that he can speak.

I have been working with the arms and head circuit.  It works fine, but for some reason the antenna doesn't work any more.  I have to get right next to it with the transmitter to get the head to move, or to get data to the arms circuit.  How do I tell the arms circuit is sending data?  I put the data cord into my mouth.  I can feel the pulse of electricity when I hit the right switch.

The bottom line is that I will probably have to get another cheap r/c car so I can yank the receiver circuit out of that.  Or, better still, I can get a cheap r/c tank.  R/C tanks usually have at least three controls: one for the turret, and one for each tread.  With a r/c tank receiver, I can wire the arms to move independently.


I got another cell phone, a simpler one than I had before.  I ran that voice changing app on my old cell phone, and sent it via bluetooth to my new phone.  OK, it works.  Great, sort of.  It is certainly a usable system.  And then I saw yet another solution: a bluetooth receiver.  I could plug that into the robot's amplifier, and send files to that via my old phone.  I found a small USB powered bluetooth receiver on eBay, and ordered it.

Of course, I need a 5 volt power supply with a USB female jack.  That was not a problem-- I have had so many false starts and dead ends on this project that I already had the equipment to throw something together.

Here's the parts list, and a photo of the final result:

9v battery clip (available from eBay or any electronics catalog)
female to female jumper wires (available from eBay)
USB female jack (I got a USB extender cord and cut it in half, exposing the wires)
5v linear step down voltage regulator (available from eBay)
solder, electrical tape

I wired the red (+) and black (-) wires on the USB jack to red and blue jumper wires, which were then attached to the V OUT connections on the step down voltage regulator.

The red and black wires of the 9v battery clip were wired to red and black jumper wires, which were attached to the V IN on the step down voltage regulator.

The inset in the below picture is of my multimeter, doing a voltage reading, with a 9v battery providing voltage.  Right on the money!  I'll be running 6v to the regulator in operation, through a 4AA battery holder with a 9v snap.

5v adapter

No doubt someone will tell me that I could get something that did the same thing without all of that work.  To that I say: it essentially cost me nothing, because I already had the parts.  So there!

I should add that I have used 9v battery snaps with AA battery holders to power my robot.  I like how quickly and certainly 9v snaps work.  9v batteries don't last long for my applications.  6 AA batteries in holders, even the cheap heavy duty ones, last much longer.

I never have covered the subject of multimeters.  All I can say is: get one.  Don't ask any questions: just do it.  It has proved invaluable to me, if for no other reason than getting my pluses and minuses correct on voltage.  They're darned good battery testers too.  I have also used mine to test resistors and transistors as well.

What's nice about multimeters is that I've found that the cheap ones work as well as the more expensive ones.  The only difference I have found is the sturdiness in the clip wires.  I settled on a $20 digital multimeter from eBay, and a $10 analog one from Walmart.

I, personally, have two kinds of multimeters: an analog and a digital one.  If you want immediate readouts, an analog meter is great for that.  A digital meter will take its good old time giving you a reading, but it will be more precise.  Both have a place in my toolbox.

So here I am at this point, waiting for a bunch of orders from eBay.  By the end of the month the robot should be up and running.

Until then, I guess I could work on the chassis, as well as the robot's front panel. 

As to the chassis: I'm going to try something simple, and see if it works.  The car chassis I am using has several supported holes that would work fine with 1/4" x 4" carrier bolts.  I could secure a piece of 1/4" thick plywood with them, using nuts to firm up the connection.  Then the robot could be fitted on top with Velcro.  The chassis would be fully visible.  To attach the front and back lights  I'll just use small brackets, gluing the LEDs to them.

Concerning the front panel, I'll be going to Fedex and have them Xerox the panel, using silver colored paper.  I'll have that laminated to keep the ink from smearing.  Attaching it to the robot should be simple enough: I should imagine that rubber cement would do the trick.

I look over my past entries, and it's really amazing how many dead ends I encountered.  And I apologize for all the blanket statements I made that were not true.  Stating that the PAM8610 amplifier would not work with the TIP31 circuit is particularly embarrassing.  If you have a cell phone with a fully working earphone jack, it works fine.  That little error caused me to go off on a wide tangent, looking for different amplifiers and so on that I didn't need to get.


                                    bluetooth speaker

A couple of weeks later, and a lot has changed.

I got the bluetooth receiver.  The sound quality is terrible.  It's completely unusable.  So all my work with that 9v USB converter was so much wasted effort.

I went to Walmart and got the cheapest bluetooth speaker I could find, a Blackweb Soundplay bluetooth speaker. which was slightly under $15.00.

I paired it with my Android phone, and the sound quality was excellent.  And then I thought, "Maybe I can modify it a bit."  The bottom of the speaker has a rubber cushion on the bottom.  I assumed this would be hiding some screws.  I was right.  The little beauty can be taken apart with just a small Phillips screwdriver.

The inside is simple: a circuit board, a battery, and a 4w 4 ohm speaker.  I cut the wires on the speaker, and wired them to a 2.5mm earphone jack.  Using a 3.5mm Y splitter, I connected the bluetooth device to my TIP31 light circuit and my robot's speaker.  Success.  The lights light up, and the sound quality is quite good.

Look over all of my past entries, and the various convoluted schemes I came up with to get the robot to talk.  This is so much simpler than any of them.

...And I spoke too soon.  It turns out that the bluetooth receiver is fine.  The problem was the 5v power supply I made.  I plugged the receiver into my computer, and the sound that came out was great.  I'm not as clever as I thought I was.

I'm still better off: with this configuration: I don't need an extra amplifier.  My Android phone  works with the bluetooth speaker, but not with the receiver.

This all started because my PAM 8610 amplifier stopped working.  I pulled it out of the robot, and while I was at it, I decided to rewire everything.  I had a bunch of wires going to the head section; basically they came down to a power cable from the battery to the top, a cable for the lights on the top, so they could be turned on from the front, and two more cables, one for each arm.  I recycled a set of 4 RCA jacks from an old tape player, and soldered on RCA plugs to each of the cables.  If I want to work on the robot, I can now take its head off completely without having to leave it hanging while I'm working.

I also made the decision to take out the old remote control receiver from the head.  I plan on buying a radio controlled tank, because there will be three controls on the receiver (left tread, right tread, and turret).  These I can use for the arms and head/eye.

Right now the RCA cables are just  sitting, waiting to be connected.  The RCA jacks will have to be labeled, once I get the new receiver.

I also replaced the old motors (which had burned out anyway) with some motors with reduction gears in them.  The motors looked like they were barely moving at all when I tested them.  I had to mark the shaft of each of the motors with a marking pen to be able to see if they moved at all.  I attached them to the robot, and added the arms.  When power was supplied, they moved around at exactly the right speed.  IU had to extend the robot's arms a bit to accommodate the new shafts, and overall they look pretty good.

Why not just cut the shafts?  I'm thinking to the future.  I might be working on some other project that needs motors, so I figured I'd keep my options open and leave the shafts intact.

You might remember the UFO detector schematic I had up here earlier.  I decided to build one.  Lo and behold it works-- that is, it detects a magnet's field.  Whether it can detect UFOs remains to be seen.  The little device works so well I bought the parts and some boxes to make ten of them.  I'll be selling them at science fiction conventions.  The detector also detects Body Thetans, Space Cooties, and ghosts, provided that all of these are also magnetic.  Since no one has ever got any of these and measured their magnetic qualities, I have to say, well, they certainly could be magnetic.  Can you prove they aren't?  Well, they must be magnetic then.  Oh, the detector also works in detecting any electromagnetic pulses that occur during a global thermonuclear war.  Mind you, the resulting flash, strong winds, radioactive fallout, air raid sirens and Emergency Broadcast System would also be good indicators.  But having this cool little device will increase your certainty.

As a side note, when I built the circuit it didn't work, even though I had followed the diagram I had downloaded.  Fiddling around, I found that a couple of the connections in the diagram were wrong.  You might remember that the original TIP31 diagram I followed didn't have a 1K ohm resistor attached to the base of the TIP31 transistor, which practically guaranteed burned out transistors.

So, lesson learned: like everything else on the internet, circuit diagrams can be wrong.



So, lesson learned: like everything else on the internet, circuit diagrams can be wrong.I bought a couple of Rock'n RC Battle Tanks from Walmart.  I guitted one and inserted the receiver into robot 4-Q.  After the usual rewiring, I can say that all systems in his main body are working now.  4-Q can move each arm independently, as well as rotate his head.  Now it's on to the chassis, and making him mobile.


It was a simple matter of buying some 4" x 1/4" x 20 TPI carriage bolts and nuts to finish 4-Q's chassis.  The RC car's chassis had some 1/4" holes in it, and by tightening the bolts in with some nuts, I was able to make a very secure platofrm of 1/4" plywood to put 4-Q on. 

Here is yet another video of 4-Q.  His working parts and circuits are complete.  Now all I have to do is some cosmetic work, and he'll be ready.

And now it's on to finishing 4-Q's Evil Twin Brother.


It's been way too long since my last post.  The Android phone I was using was nothing but trouble.  It was like that old nursery rhyme:

There once was a little girl
Who had a little curl
Right in the middle of her forehead.
When she was good, she was very, very good.
But when she was bad, she was horrid.

I was using a Voice Changer Android app,along with that Box speaker.  It worked beautifully,up to the point that my Android phone started acting up.  So I rethought everything.

Yes,the Android app was fin and simple, and it was loud enough to get the robot's lights blinking.  I got myself an Acer laptop with Bluetooth.  The BloX speaker worked, so I kept that.

I downloaded a program called Balabolka,and used the standard Microsoft David Desktop voice.  Balabolka
  does text to speech, among other things.  I lowered the voice's pitch by -10,and saved it as an audio (WAV) file.  I opened up Audacity (mentioned earlier in this page), and under effects, amplified the voice by 16dB.  I then went to pitych and changed it by minus 6%.  It doesn't sound exactly like the old 4-Q voice, but it comes close.  Additionally, I can do things like import text and amplify the voice further, which I couldn't do with the Android.


Yes, I haven't updated this in a long time.  The Evil Twin Brother bot is done, and updates will follow.  Here is a photo of he two now complete bots.


Update: 07/08/2017  

This is some footage of the Evil Twin Bot.  I'll be makjng a third bot soon, and will try to post a step by step guide.


OK, so the Bipolar bot is done.  In assembling that robot, i made several finds that would make any robot builder's work  easier.

EBay has a 2.7 GHz remote control and receiver for tank toys.  For a robot's innards, it would be ideal.  It has things it can control (treads and turret).  I use it to make my new robot's arms move, as well as his "camera."  It works really well, and is a lot cheaper than buying a tank toy and tearing it apart.   It's listed as "
2017-New-6CH-2-4Ghz-30-meter-remote-control-with-receiver-board-for-tank-car."  It costs $9.90 postpaid.

robot control

I went to Amazon and bought a 16" MiA2 Abrams tank, to use as a drive for my new robot.  It was better than I expected: four screws hold the fancy googaws on it.  Unscrew them, and clip the wires to the top part of the tank, and you have an excellent platform for a robot.  All I need to do is put some E6000 on the bottom of my robot's torso, and hold it in place until it dries.  No modification is needed.

abrams treads

I found a Bluetooth speaker at Big Lots that works perfectly for my robots.  Gone is that worthless Blox speaker!  It is a Polaroid Bluetooth speaker, with a tinkerer friendly feature: the electronics are all on a plate screwed on the back.  Remove the plate, snip the wires, and you have a robot ready speech module.  It uses two speakers.  You can attach two of the lead toi my robot flashing light sync circuit, snd the other to a speaker.

bluetooth speaker             speaker panel

And here he is, the robot of the hour, Bipolar Bot.  Yes, he still needs some painting and sanding.  And yes, that is a saw blade.

bipolar bot

I've been using large Utz cheese ball containers (available at Walmart) for the bodies of my last 2 bots. The label can be taken off of the jar by pulling off as much as you can, and then applying baby oil.  Wait a few minutes, and scratch the rest of the paper off with your thumbnail.

utz cheese balls jar4

At Inconjunction, I mentioned in a panel that robot builders should never throw anything away, and that they should keep a junk drawer of parts and such.  A fellow panelist (one who likes to build robots with vacuum tube parts instead of transistors) said that he has been making robots for years, and has several barns full of junk, waiting to be turned into robots.  Now he is a role model for all of us!

Update: 9/1/2017

I uploaded a page that might be of interest to robot makers.

How To Vacuum Form Plastic on a Low Budget