Let's Make Robots!

Problem in programming and working of Start Here robot

hello everyone.

Im really happy and excited to tell that iv completed building my first robot, but at the same time in sad as its not working properly. Actually its behaviour is some what different, Im posting videos with the program i downloaded on microcontroller.

Any help or comment is appreciated!!!

the program goes like this


symbol dangerlevel = 70 

symbol turn = 300 

symbol servo_turn = 700 



readadc 0, b1

if b1 < dangerlevel then

gosub nodanger


gosub whichway

end if

goto main




high 5 : high 6 : low 4 : low 7





gosub totalhalt


gosub lturn 

pause servo_turn

readadc 0, b1

gosub totalhalt


gosub rturn

pause servo_turn

readadc 0, b2

gosub totalhalt


if b1<b2 then

gosub body_lturn


gosub body_rturn

end if




high 6 : low 5 : low 7 : high 4

pause turn : gosub totalhalt




high 5 : low 6 : low 4 : high 7

pause turn : gosub totalhalt




servo 0, 100




servo 0, 200




low 4 : low 5 : low 6 : low 7 

Servo 0,150

wait 1


I have attached the video which clearly shows its behavior. what can i do to change it to function properly?

MOV01514.3gp544.98 KB

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My guess is that most people will not download the video. Can you upload it to youtube?

wat i mean to say is i downloaded the program on microcontroller and im posting the video which shows how it works after writing that program on microcontroller.:)

Your code looks fine but how about check the connections are good on the motors? And also going to the correct pins on the board, i have my left motor connect to both pins on A and the right motor is connected to B,  you can swap the wires over if the motor is wrong direction but its just as easy to alter the code


hope this helps a little

well i tried that, but its not working.

the main problem i see is its not moving as shown in  the video on start here page.

iv seen many other ppl who made this and its just working fine but this one is like moves a little stops but  the servo keeps rotating left and right. i tried testing every part individually and they work fine but if i program them to work simultaneously they dont work like that.

From the video, it looks like your robot is getting stuck in the 'whichway' routine. It never seems to complete that routine and decide which way to go. The servo is also behaving funny. It turns more left than right and seems jerky.

Your robot could have a wiring problem, be affected by electrical noise, or have a power problem.

Power is easiest to check. What kind of batteries are you using? Are they brand new and/or fully charged?

In the start here instructions, under the 'Programming' section, did you verify that the sensor is putting out data on the b0 variable? Does the data change in relationship to the distance from the sensor to your hand as you move it back and forth?

You stated that you tested each part individually and they all work. Statements like that are not terribly useful to us. Something is wrong, and if it is something you overlooked, we cannot know that. So take us through what is really happening. Explain what you have tested and what the results were in some detail, and we'll try to provide more assistance.