Let's Make Robots!

Constrain not really working

Hello guys... here is the thing :)

I have this part of the code

Ardumoto and arduino

Hi there :)


I have a simple problem... I combined Arduino and Ardumoto.

Now I have 6x 1.2NiMh  AAA batteries of 800mAh each... I charge them up.. it shows 1.2V when I measere them but when I connect to arduino it says 6.3 or something... well, which is enough... theoretically


Now my problem is that sometimes my Arduino just resets if I pull strong of the motors... with a simple 40 pwm no problem... with 255 it resets...

what can I do?


should I go for AA? or 2x9V in parralel with 5V regulator?

PID problems...

Hello guys,


I need to make a line follower for a competition...

I use:


Ardumoto shield

30:1 reduction motors

QTRA sensors...


now following 3pi I got this code:

atmega32 INT2



I have an atmega 32... I want to use all of the 3 interrupts... I got problems with INT2...


I set it up as a falling edge and via a 10K resistor put the button to ground...


while(bit_is_set(PINB, PB2));


//init interupt

GICR |= (1<<INT0) | (1<<INT1) | (<<INT2);





the problem is that after the while... when the interrupts are initialized... the pull-up drops out...

Battery charging



I have this battery:

it has 6V, 1.3Ah... I don't have a charger... on the side says:


cycle use charge 7.25 - 7.45V

Trickle charge: 6.8 - 6.9V

and something about 0.4A


avr 38khz modulation problems

Hello guys...


I have some troubles... I take a look at AVR Calc and at 8mhz I can make a CTC of around 37.98khz signal wich lets say would be ok for 38... the problem is that there is not enough explanation of how to make it...


for 8mhz, 1 prescaller, ,on 8 bit timer:

OCR = 0xD2

TCNT Base = 0x2D

CTC = 37.9147khz

Error = -0.224%

overflow: 32.000 uSec

PWM normal/fast = 31250.000 hz

pwm phase correct 15686.274hz



can you please help me how to set the code for this?

L293D not working even if its wired correct



I have an L293D driver... I connect logic VSS from regulated 5V and the atmega8 too... the VS is connected through another 5V regulated voltage... it drives a little motor... but it doesn-t drive my tamiya box... everything is set up correctly and tested... why is this? when I measure the voltage on the motor pins it goes 4.95V and -4.95 every 5 seconds as it should go... but after I connect the motors and remove them, I measure again, I got 0.02 and -0.02... whats the problem?

phototransistor problem



I used to have my QRD1114 with a 10K pull-up resistor and everything was fine... but look I replaced it with IR emitter and IR receiver/phototransistor... I put a 12K pull-up to 5V on the collector, and between the collector and the resistor I get the signal... but I got only around 1.4 - 1.6 why?


Any simple ideeas?

AVR UART not really working



I'm still developing a code here...


can somebody test it out somehow?


I don't know what is the problem


the reciever or the transmitter



here is the code for the reciever:



tiny2313 pwm timer1 does not work the OCR1A and OCR1B



I want to control 2 DC motors...


I set the Timer1 for fast pwm no problem... I run at 4 mhz....


what prescaller I need?

and even if I set the OCR1A and OCR1B the speed is constant... any ideea?





TCCR1A |= (1<<WGM10)|(1<<WGM11)|(1<<COM1B1)|(1<<COM1B0)|(1<<COM1A1)|(1<<COM1A0);

TCCR1B |= (1<<CS11)|(1<<WGM13)|(1<<WGM12); //prescaller