After three years of robot building and still having to learn more and learning day by day I can say that I gathered enough experience to build a robot out of a toy. All I needed was some basic tools (screw driver, driller, e.t.c.) a toy, to be used as a base some electronics (Two OEM Basic Stamp chips, photoresistors, IR leds and decoders e.t.c.) some plastic sheets and some metal stand offs...

 The basic idea was building a almost totally autonomous robot capable of recharging itself by a top-level solar panel but not having enough money is a serious problem (I have already gone over-budget but it was worth trying). The solar panel needed for recharging the NiMH battery in a reasonable time (4 hour charge aprox.) costed 60Euro ( 12V @ 5W). Also by the end of the month a change in prices is expected in my country (Hellas - Greece). But even without having a solar panel the proccess can by analysed (program code - video cover - algorithm) and it will be (but don't expect to recharge itself?!?!?!).

That being the situation, by building and displaying my robot I will also try to give to you the basics of advanced sonar scan and object avoidance, photovere function with object avoidance, how to check the battery voltage with BS2 (RC circuit, 555 as ADC and maybe by an external ADC(I try to explore the BS2 and not ADCs but it will also be a way to show serial communiation with BS2!!!. If the samples from Analog Devices arrive soon enought using the ADXL 202AE+ as a dangerous incline finder will be displayed.

Generally the lack of money leaded to a lack of sensors but hoping to be able to cope up with school (I'm a 3rd grade senior High school student and I have to study long hours in order to give exams by the end of May and be accepted to a University!!!) I'll enrich the tutorial.

The contest was only a motivation being or not able for me to take a place doesn't really matter!!! I only hope to be able to finish before the voting ends....


STEP 1:  Building The Robot

Making a choise:
Having build two tank robots out of toys before I had to make something more advanced and better!!! The first robot was made out of a caterpillar, it was very short with the batteries in the back making it difficult to climb anything. Also the maching was very bad (connection of the servos to the wheels). The second bot was also very short but these problems were fixxed!!! NOW I will be building a taller robot displaying various analog sensor (heat seaker, light seaker) and digital ones (sonar, IR) able to climb almost anything and in a very high speed!!! Also ways to improve the toy's machining is shown (how the gear system is held together tighter!!!). The past problems are overcame and everything is kept simple!!!

So this is what i came up to!!!

So I have also to mod it so I can mount the electronics and use the motors and the case!!!
And this video shows how:

After that the robot looked like this:

And after removing some unwanted plastic parts:

Then some extra screws had to be placed to ensure the smooth and successfull fuction of the motors gearset!!!  :

The red boxes show where screws were added in order to re-enforce the gearset and hold tight the wheel axes!!!
Note: Some hot glue is placed to protect the wires!!!

And from above!!!

Now where we'll be mounting the BS2 OEM (a special version) Board... For this purpose I drilled some holes in the center of the case so the weight of the vehicle is balanced both in the front and the middle!!!

And should really look like this for instance:

So here I'm having the robot finished finally!!!
The first thing we had to attach was the battery. For a battery I chose a NiCad @ approx. 600mA to power both electronics and mechanics!!! To reduce the noise level I used some 0.1?F and 0.01?F caps near the noise production units such as IC's and motors!!! The bad thing is that the battery is wasted in less than an half hour of roaming!!! The good thing is that in this half hour it's nearly unstopable!!! The battey can deliver huge amounts of energy at any time!!!
Now where to place the battery???
Tank vehicles are usually able to overcome many object in their way!!! My robot is no exeption!!! But having the center of weight high placed reduces the height of the objects that the robot can pass!!! So the battery was placed in the lowest position that was able!!!
And here we come!!! Note that the battery is mounted on a soldering breadboard!!!

And the battery board!!!


And this is what the robot should look like!!!


Now in the next level what should be placed is the Stamp Board... Why because we need the top level for the sensor board (we'll talk about this in a minute!!!)
And vualla!!!

And here is the Power LED mounted on the front of the vehicle:                                           (It can turn the night to day!!!)



But what is a robot without sensors and a powerfull H-bridge... A human without senses and legs!!!
For these reasons I builded a board to host all these items. I could have used the board's breadboard (ruster) but I needed the sensors to be as high as possible!!! The sensors included is a pair of photoresistors, a pair of NTCs and two pairs of IR receiver - transmitter (TSOP1730 and some single IR LEDs!!!).
So these are the schematics of the sensors 1)Note than the IRF9540 is for driving the LED circuit as it drow up to 350mA!!! 2)Note that the 555 circuit isn't used yet... The H-bridge consume too many ports of the Stamp and will be connected to any co-microcontroller (probably AVR) later!!!

The board is a simple soldering breadboard as shown below:

' Set the variables and their
' place in the RAM
IR_det_Left  VAR Bit
IR_det_Right VAR Bit

' Initialize the program
FREQOUT 11, 200, 359
LOW 1  'Turn off the
LOW 7  'IR LEDs

DO
' The main program foe detecting the objects
' a short burst and emendiately after the detection
 FREQOUT 1,1, 42000
 IR_det_Left  = IN0
 FREQOUT 7,1, 42000
 IR_det_Right = IN8

' Conditions of turning... 
  IF (IR_det_Left = 0) AND (IR_det_Right = 0) THEN
   GOSUB go_back
  ELSEIF (IR_det_Left = 0)  THEN
   GOSUB turn_right
  ELSEIF (IR_det_Right = 0) THEN
   GOSUB turn_left
  ELSE
   GOSUB straight
  ENDIF

LOOP

' The main subroutines table
' this program has only subroutines
' about the motion!!!
Straight:
 HIGH 6
 LOW  2
 HIGH 14
 LOW  15
RETURN

Turn_Left:
 HIGH 6
 LOW  2
 LOW  14
 HIGH 15
RETURN

Turn_Right:
 LOW  6
 HIGH 2
 HIGH 14
 LOW  15
RETURN