Let's Make Robots!


Play with pets
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This is a pet toy robot, not a pet robot like Aibo

But children like it more than pets do 


this is second prototype of my Pettoybot. First one was on $10 toy RC car platform. but it runs too wild, so I made this gentle two wheel one caster version.

 Mission of this robot is play with pet. So I give him a sensor to detect pets movement and tell him to follow the movement of pets.

 Pet detecting sensor is  just the same one in the portal lamp in ordinary house. the lamp automatically lights on when human step below it. It uses PIR (Pyroelectric Infra Red) sensor, that detect change of infra red right not the infra red light itself. Just continuous light up infrared light to the sensor dosen't make any signal. 

Human and mammal  pets radiate infrared lights so their movement make change of infrared light that can detectd by PIR sensor. And there are a lot of infrared light already in our environment so any thing that move can be detected by PIR sensor

But when robot with PIR sensor moves the PIR sensor makes signal crazily. so there was no robot using the sensor yet.

(Rodney Brooks already made robot Genghis with this PIR sensor in 1988.)

I made the solution :)  When sensing, stop the robot.  go and stop to sensing go and stop..  repeat this~ 

 And I gave him a Sharp range sensor that detects 2~80 cm. I installed the sensor slantly to the down front so it can detect cliff and obstacle.  When the range is too far it means there is cliff and the range is too short it means there is obstcle.

the brain of Pettoybot is Arduino. mmm Ah, it ha slaser pointer to play with cats 

The case is made of fiberglass composite and paintng and long time of sand paper work.

It takes about two month to make this robot

 and I will add auto self recharging function and  recharging station  with IRbeacon


major parts 

MCU: Armega128 * 1 , Atmel

PIR sensor:  LHI-878 * 4, Perkin Elmer

range sensor:  GP2Y0A21YK * 1, Sharp

motor drive chip: L293 * 1

PIR sensor signal amplifying OPAMP: LM324N  quad opamp 

two Tamiya truck wheel and a caster

double gear box by Tamiya 





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ahah that's great :) I especially like the case, really well done! hoh did you made it? I mean, the shape and such..

lol the video!

Yea I made the case with fiberglass and epoxy resin. 

and painted urethan acrylic paint (for car) by hand brush

But it was not sleek enough. so I rubbed it with sand paper for L~ong time

and paint again rub again~ again and again  ~


but how did you shaped it ? i see the lower part has a small "step" to fit the upper one.. did you used some kind of mold?

i'm really interested, it looks toooo good

Befor making mold. I had to made 'plug' with bonded thick styrofoam board using cutter knife and sand paper 

Plug is like mold for making mold.  

and coverd plug with fiberglass and epoxy

after it dried, I did  sanding and sanding

and did separation treat like waxing and polyvinyl ahlcohol coating with cloth

on the plug, I did fiberglass composite work to make mold.

then separate plug and mold

inside the mold I did last fiberglass work for final robot case 

and separated the case from mold and painted  and did sanding 


 in short

1. make plug  

2. make mold on the plug

3. make case on the mold


It was about two weeks of hard work in fiberglass dust and styrofoam dust, paint dust 


 I uploaded pics in flickr. 




well it looks like an hell of a work! :) but the results are great! I could try myself in future :)

kudos man! 

Wow, very very awsome casing. Smooth and clean.

Hey this is a cool idea.

How about making the bot move away from the cats, in a sort of fleeing way, maybe then the cats will consider it a pray and have fun hunting it ;-)

 ;-) Thomas


I'm thinking about it

reverse action? :)



Very nice work with the "frame" :)

I think a link to our PIR-component would be in place: http://letsmakerobots.com/node/858

And - I cannot stop thinking; I know you are standing still to detect with the PIR.. However, cats like the moving laser.. Perhaps you'd want 

Either to..

Do some slow moving with the robot, just slooow forward / turn etc - with the laser on. i think that would get the cats going.


Add motion to the laser (a servo, perhaps) something, so that the pointer was sweeping over the floor - I think that would make them going :)


VERY NICE AND ORIGINAL WORK! Nice to see that kind of actual DESIGN in here :) Cheers! 

I came t know that Rodney Brooks in MIT already used the PIR sensor in robot Genghis in 1988. 

I read about it in his book 'Flesh and Machines' several days ago. 

But he didn't mentioned about difficulties about using the sensors in moving robot.

Is there any other way to use it ?