Let's Make Robots!

Tank 1.0

Navigate , Avoid bstacle, Avoid to fall, Seek for Light
AttachmentSize
taratura_array_5__photo.xls21.5 KB


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Handcrafted Base hold containing:

-5x AAA battery

-2x solar geared motor

-Mother Board

-Geared wheel drive

 

proto1.jpg

Mother Board features:

- L293D motor driver

- DC Buzzer

- Lo dropout 5V regulator

- I2C hub (not used)


robomobo.jpg
Handcrafted 5x LDR array sensor
array_R.jpg

Front sensors:

- 5x LDR array

- 2x Sharp tilted telemetric ranger

sens.jpg
Raw Geared 4 wheel drive wolf.jpg
Download my BasicX code here:
tank1.4.zip
code.jpg

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Great robot, too much capabilities, avoid objects, avoid edges, light seeking, very good idea for the wheels.

 

Is awesome, it has a real sense for whats around it. 
  Very smooth movement, nice and controlled. Congrats on all the hand crafted components too, nice work!
Can we get a little more information on the Handcrafted 5x LDR array sensor?

there is not much to say

it consist of 5 LDR which cover 90 degrees

the structure is built with 1 mm plastic sheet

each LDR is inserted in a pipe ( drinking straws)

each single LDR is pulled down by a resistor

the back of each LDR pipe is sealed with black paint

 

Did you try to match the LDRs first? I found sometimes LDRs of the same type and even from the same batch have slightly different resistances.
i took a bunch of 10 ldr, and i chosed the more similar 5

Once you place them into tubes ..... you can forget matching them - the length of the tubes they are in and the geometrics of the holder array has a big influence.

Therefore its better to equalise them by software........ (by my experimentation you are only talking of a 20-40 decimal difference anyway between LDRs)

The Tubes have to be really-really DARK (including backend) (this goes also for IR LEDs) if you plan to use as directional sensor.

yep, software tuning is necessary to obtain perfect results

 

check this file

http://noise0.altervista.org/5photo.zip

there are results of raw test on the sensor...

can you suggest me a may to obtain a smoth equalization?

 

I have tyed this :

 

if LDR1_reading is between (0.100) then

    LDR1_reading*=0.99

else if  LDR1_reading is between (100,200) then

   LDR1_reading*=1.20

else if  LDR1_reading is between (200,300) then

   LDR1_reading*=1.11

 

and so on

 

but this way produce unwanted steps of  comutations  wich make the behaviour not smoth

 

i think th right way would be somethk like:

y=  a*x^3 + b*x^2 +c*x +d   and so on

 

but have no idea how to calculate a,b,c,d,e,