Let's Make Robots!


Telepresence. Human/Computer interaction (speech, movement). Autonomous mode using A* in a controlled environment.

Update 02/08/2015

Wanted to give an update on Artie's progress.  Still working on the improved base.  I've laser cut a prototyped control box and wired up a Sabertooth 2x32 to RC control using 24V.  I tried using 12V like with the Power Wheels chassis, but it would barely move.  Hooked up the on/off switch to an automotive relay, and now it can handle grass and slopes easily, as well as fit through doors without any fancy maneuvering.  Next up is cleaning up the control box, and reconfiguring the telepresence program on the laptop to control the motor controller.

Update 10/29/2014

Just wanted to pop in and give a quick update, telling people to stay away from Dynamixels.  I've basically hit a dead end with them, as the support for Dynamixel SDK is outdated and generally terrible.  Unfortunately, this means I have to go back to the drawing board and redesign the pan/tilt assembly to use hobby servos instead.  It's going to take a while, because I'm pretty sure the beautiful machining of the current assembly was a one off thing.  I'm currently drawing up designs for parts that will be laser-cut in acrylic.

Upate 09/28/2014

Having issues with my Dynamixels on the head/neck, so I'm moving on to other stuff while I'm waiting for a USB2AX to arrive.  A couple weeks backed I picked up a craigslist special.  A Quickie P-190 for $50.  So I'm switching out Artie's Power Wheel base for the wheelchair motors.  Still using the HB-25's for now, but contemplating moving to a Sabretooth 2x25.

Anyways, with this update, I'm showing that I stripped down the base, removed the electric brakes, and prototyped Artie's body sitting on top of the new chassis (zip ties for the win).  I got him driving down my driveway, but wasn't able to hold the camera and drive him at the same time.


Update 08/18/2014

Finally figured out how to get the Dynamixel servos to be controlled by the XBox controller through my Java program.  Using a USB2Dynamixel dongle and the simpledynamixel processing library (https://code.google.com/p/simple-dynamixel/), I was able to get pan working.  Unfortunately, found an issue with the mechanical design of the tilt mechanism, so have to go back to the drawing board on that one.

Update 03/24/2014

He speaks!  Re-did the head, using a bunch of 3D printed corner brackets to hold it together vs glue like before.  Also installed a speaker from a spare computer speaker set I had, as well as built an access panel on the top of the head (vs before where I just pulled off the top that was wedged in).  I also made the Arduino interface a little cleaner, using a prototyping shield to sit on top, vs the separate breadboard I was using before.

The voice in the video is not his eventual voice.  It will sound more high-pitched and robotic as I'm going to feed the input through a modified kids voice changer toy.  Also, the audio in the video is just a pre-recorded sample from the ATT Natural Voices website.  The plan is to actually use FreeTTS for speech synthesis.  But I wanted to test out the system before going to bed, and of course wanted to show it off here!

Update 03/11/2014

Posting a photo of RT at the SXSW Create event.  Wish I got more photos/videos, but I was too busy driving the robot to man the camera.


Update 03/07/2014

Hooked up Neopixel ring lights and posting a video of it going through the different patterns.

The eyes can do 10 different patterns and 8 different colors.  When not in "attract" mode, the patterns and colors are set using serial commands over usb from the host computer.

Update - 03/03/2014

More updates.  Just recieved a pan-tilt system hand-machined by a friend.  Thought some of you might be interested in photos of it, so I'm adding a bunch of different views.  You can see the NeoPixel LED ring holders on the head now and the ultrasonic sensors on the front (positioning will change when second layer is added on).  Also, I plan to cut the PVC pipe for the neck in half to aid with balance issues.

New images of the latest design of RT-01.  Using only one section for the torso instead of two until the second layer is actually needed. 

RT with paint job


The RT Series robot will be a 5' tall robot.  It uses two geartrains from a Power Wheels ride on toy, and two Parallax HB-25 motor controllers for motor control.   An Arduino currently serves as an interface between the Acer One netbook (the same one on Geoffrey), and the motor control.
Eventually the RT-01 robot will be jam packed with processing power and sensors.  Currently slated is.

  • 1 Microsoft Kinect w/ depth sensor, RGB camera, and 4 microphones
  • 4 other web cameras (2 in the eyes, 1 in the back, and one pointing down to the ground to track motion)
  • 1 speaker unit (located in the "mouth" area
  • 8 HC-SR04 Ultrasonic sensors
  • An array of bump sensors (amount and kind tbd)
  • 2 microphones located on the sides of the head.

For processing power.

  • 1 - Intel 1.7 ghz processor with 2 gb RAM and 80 gb hdd
  • 1 - Arduino Uno @ 16mhz
  • 1 - Arduino Mega 2560
  • 1 - Raspberry Pi
  • 1- Dual Core Android Tablet @ 1.2 ghz

These processing systems will be connected together to provide modularity.
The system will be open source, and both the hardware and software process will be documented for replication.

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Nice project! I'm experimenting with Arduino and HB-25's myself and have hit a wall. I'm trying to use Dual Mode (1- arduino, 2- HB-25's) I can get both motors going in the same direction, same speed. But can't seem to get them going in opposite directions or one running while other is stopped.

Are you using dual mode in your RT-01? If so, could you post some sample sketch?



I really love the improvements you've made to RT. Of course, I'm big into wheelchair motors and I have two sets in the basement waiting for me to get the time and concentration to build groucho (also planned to be about 5' tall).

One problem with your videos: the second to the last one appears to be private and can't be viewed, at least by me. The others were great, and it looked like you were having fun running the chasis over the grass. :)

I really hope that you have fun with it.

And now for the song: "I like big bots and I cannot lie..." :)

Fixed the privacy of the 2nd video, thanks for the heads up.   If you do get around to the wheelchair motors, I highly recommend using a Sabertooth.

oh - and sorry about the vertical video syndrome everyone.  My fiancee is an iPhone user and she took the video so it's habit.

I already have both a Sabretooth and another brand at home. Both 30 amps per channel.

I'm not sure that it will be fast enough for a balancing robot though. I'll find out.

Hi Luke.  I was looking around Walmart the other day, and wondered what you think about the pros/cons of using the Powerwheels motors/wheels/gearboxes?

Also, have you looked into using some of the pan/tilt stuff from Servocity for RT-01?  Some of them are quite rugged.



whoah, I totally missed this comment before, sorry for the delay in response.

I actually like the Power Wheels motors/wheels/gearbox combo.

They are 12V, so they will run off of 1 battery.  They pull a max of 23 amps stalled, but can handle up to 135lbs of load (for 2).  You can build a robot out of PVC and wood and have it be very tall but light.  Having a tall robot looks cool, but having it light makes it safer to bring out to crowds.  They are also cheap to replace, because if you keep an eye out, you can find used Power Wheels for cheap because parents just want to get rid of them once their child outgrows them.  Also, because it is recognizable to a kid, it's very inspirational.  

I know one of my influences is a crappy movie called "And You Thought Your Parents Were Weird!"


It's a terrible movie about kids that build a robot and their dead father's spirit inhabits it.  Terrible, but I saw it when I was in early middle school and seeing a robot made out of a Shop Vac and a colander (vs the slick robots of the time like J5, Terminator, Robocop, etc), really inspired me to make my own robots.  So when a kid sees the Power Wheels wheels and goes "hey we have one of those, you built a ROBOT out of it?", I have hope that maybe I inspired them to try to imitate what I did.

Now, the con.  The biggest con of using the Power Wheels assembly is that the wheels have barely any traction.  It's cool because you can do awesome spinouts, but sucks because they don't work well on anything other than a flat smooth or carpeted surface.  This lack of traction is done on purpose so that kids don't get whiplash when they jam on the accelerator switch.

I'd say, don't buy one new to disassemble.  Instead, troll craigslist to find one being sold for under $50, or if your town/city has bulk trash collection, you will sometimes find them on the curb.  Once I found 3 sitting beside a clothing/shoe recycling box, so I called the number of the company on the bin and they let me take them.  They work well with the Parallax HB-25s, and I'm experimenting with Sabertooth 2x32 right now.

As far as the Servo City pan/tilt brackets.  I have looked into them, but they seem to be too expensive for what you get.  Especially if I just take some time and take advantage of tools I have available to me.  But, if enough time passes and I get lazy, I might actually go that route.

Thanks very much for the writeup Luke.  I like the "inspire kids" point, I hadn't thought of that.  The traction issue is important to me.  I could build in slow acceleration to help, but I think I'd want better traction anyway, which means better wheels or alterations to theirs.  Sadly, I'm not much of a troll, so I overspend at times.  Cheers.

We seem to share similar building styles and enjoy personality from our machines.....I will be keeping an eye on your future gadgets!


Nice.  I wanted to switch mine to an XBox controller...tried an IR remote and also an RC set.  I don't like either.  I suspect the software on the robot side for interpreting the RC stuff creates timing issues with the Arduino running everything else, as it had to measure duration of RC pulses.

Does the XBox controller send out IR signals or something else?

RT is getting more distinguished looking everytime you post.  Perhaps you are planning dinner party appearances.

I am hoping to have some brain code for you by end of year.  Like to find a way to get your design input sometime.




I'm not quite sure what the XBox Controller sends out.  I believe it is proprietary 2.4ghz RF.  But, I can explain what I do.

The XBox controller I use is this.


It comes with a USB dongle that plugs right into the PC.  I then use a library called jinput


I use it to initialize the library and read the input.  I then communicate with the servos using the simple dynamixel library.

However, it doesn't seem that you aren't alone with wanting to use an XBox controller with Arduino.  But, if you don't have any luck, I've seen some articles about using a Playstation controller with the Arduino (both have similar buttons).

Good luck!