I got an early start on the 2014 Robot Club project – I call it Talkbot.  This robot moves on the floor until it bumps into something.  In “friendly” mode, he speaks a polite excuse, backs up and keeps moving.  In “rude” mode, he speaks a rude comment, backs up and keeps moving.

Talkbot is 14″ x 11″ x 8″.  His body is made from a white Rubermaid trashcan.  His arms are 1″ PVC pipe and swing in unison, freely.  On top are two “ears”.  the right ear is a toggle switch for friendly/rude.  The left ear is a toggle switch for the power.  Talkbot’s face is comprised of 2 RGB LEDs for eyes, and a 2.5″ PC speaker for a mouth.  His front bumpers are a pair of microswitches with straws glued to them.

The undercaridge is a single sheet of .05″ polystyrene (transparent plastic).  I’ve cut holes for the wheels, mounting components, and for the front bumper wires.  The indented “handles” of the trashcan make a nice resting point for the polystyrene sheet.  To keep the undercaridge from falling away from the body when he gets picked up, I have an aluminum slide-bar with a wooden peg.  I experimented with a few different rear caster wheels to get the right height – it needs to have a low clearance for the bumpers to work well.  If it is too tall, it makes the front lip of the body scrape against the ground.

Inside Talkbot are the electrical components.  The brain is an Arduino Uno with an Ardumoto shield from Sparkfun.  I also use a small breadboard for connections and to mount the Speakjet and LM386 audio amplifer ICs.  The gear motors and wheels are a bundled set from Solarbotics – they are a bit noisy, but the price meets my budget.  I’m using two 9V batteries to power Talkbot – one for the Arduino, and one for the LM386 amp (so the voice can be heard over the motors).   The left ear is a DPDT switch to accommodate the 2 batteries.

When Talkbot bumps into something, he has a short list of phrases that he speaks:

Friendly mode:

  • I’m Sorry
  • Excuse Me
  • Oops, Sorry
  • Pardon me

Rude mode:

  • Move it!
  • Look out!
  • Move Over!
  • Get out of my way!

Experimenting with the Speakjet IC for the first time was interesting.  I used an Arduino Speakjet library from  It comes with a limited dictionary, so I had to experiment with the utterances to form the words I wanted.  It turned out ok, but I’m concerned that the kids will want to customize their robot’s speech which could be a challenge in the limited time we have available during class.  Also, the Speakjet chip is a bit pricy which is driving up the total cost of the robot – I’m trying to keep it in the $100 – $125 range.  I’m planning to experiment with a RoboVoice chip which is less expensive and should be easier to work with (basic Text-to-Speech) if I can ever get the guy to secure his website so I can place an order!  Parallax also has a nice one, but it’s too expensive for me.

I’m really happy with the way Talkbot turned out and am thinking ahead to the prep work that will be involved with creating kits for the students in my Robot Club for next year.  I like the fact that the body is easy to decorate (using markers or paint) – that’s been a challenge with other robots I’ve designed.  My wife and kids agree that he’s entertaining and attractive, so I think the students in Robot Club will be eager to build one.


DSCN0011  Front view of Talkbot

DSCN0014  Bottom view of Talkbot

DSCN0019  Inside view of Talkbot.  A spaghetti mess of wires!

DSCN0018  Close-up view of the electronics.  An Arduino + Ardumoto shield at the bottom.  A breadboard with the Speakjet and amp ICs in the middle.  Gear motors with wheels on top.


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