problem in the motors og the robot

[hossam abdo]

this is a line follower robot .


there is a problem that when i connect the motors(M1,M2), the supply reading be 1.5 volt instead of 5v.
and when i remove the motors, the supply back to 5v.
also the motors didn't work.
what is the problem?!

please reply as fast as possible

thanks in advance.

 

[tpetar]

At first you should use electrolityc capacitors at voltage regulator acording to manufacturer datasheets advice.

What voltage regulator you use 7805, 78S05, 78L05 ?

What is power of motors, what voltage and current they need ?

What is sensor ? What you use there ?

Switch connections on lm339 4,5 and 10,11

 

[hossam abdo]

for the electrolytic capacitors , i use 9v battery (power cell) so why i need the capacitors?

the voltage regulator is L7805cv

the motor is 1.5v, motors of the toys,i don't know the current they need

the sensors are ir sensors

the lm339 4,10 are used for the reference voltage and i put it in 2v
and 5,10 take from the sensors output

 

[tpetar]

You cant replace capacitor with battery its not the same.

Voltage regulator is not transistor, its integrated circuit, its very complex chip with multiple parts, to make him to work you should use it with capacitors.

 

[hossam abdo]

you mean at the input of the regulator(after the battery) , i must use capacitor?
what is the capacity of it?

 

[prmurthy]

It is motor problem please check if they have 0.1uF caps between + and -. Moreover L7805 is low current regulator it may blow if you exceed the limits

Thank you

 

[hossam abdo]

It is motor problem please check if they have 0.1uF caps between + and -. Moreover L7805 is low current regulator it may blow if you exceed the limits

Thank you

what is the function of this (0.1uf) capacitors?
for the L7805, what can i do to avoid this problem?
thanks in advance

 

[prmurthy]

Hello

Please go through this page

**broken link removed**

Thankyou

Replace L7805 with normal KA7805 or similar.

The prefix L of 7805 is for low current.

 

[tpetar]

L7805CV is not low current its 1,5A

78L05 is low current 100mA

78S05 is 2A


Dont mix 89L05 and L7805CV not the same!!!!

http://www.datasheetcatalog.org/datasheet/stmicroelectronics/2143.pdf

 

[prmurthy]

Hi tpetar

Sorry, I misread that L7805 as 78L05. Extremely sorry.

Hossam can use LM323 for higher current.

Thank you for pointing me for the mistake.

Thank you

 

[tpetar]

@prmurthy its Ok!

@hossam abdo :

1. Try motors direct on battery 1,5V to see is motors ok.
2. Use voltmeter to se what voltage you get on Q1_M1 and Q1_M2 (of course sensor must working!).
3. I think that you switch pins connections (I write this before) on LM339 (4 with 5, and 11 with 10).
4. What IR sensor you use? Is this IR LED, IR transistor,.... is it working ? Lightwave is ok with IR sender ?
5. Put capacitors on 7805CV at Input point 330nF and on Output point put 100nF and 10uF (cap voltages at least 16V) !!!!!

 

[hossam abdo]

Re: problem in the motors of the robot

can i use 2 cellular mobile battery (each one of them is 3.5 volt)
or use 4 battery (each one of them 1.5v)
instead of the regulator ?

 

[hossam abdo]

1-
2-

when i run the motor with the first battery (the motor doesn't run unless the battery is 9v when)when i use the same battery
but when it down to 3 the motor doesn't run

when i use a battery as the second (1.5v)the motor run normally

what is the difference between the two batteries, and why this occurs?

thanks

 

[hossam abdo]

please, how to protect the battery from the sc(short circuit) of the motor
i use 1.5v motor with 3 v battery


please reply as fast as possible

 

[tpetar]

Supplied voltage to motor must be adecuate to motor needs, accordint to motor datasheets and data. If you supply higher voltage motor will die. Motor and circuit protect from motors spikes with capacitor and diode.

How do you mean to protect battery from motor short circuit?


Take one battery 1,5V and connect it to motor plus and minus. What is situation,motor working or not ?

 

[mrarslanahmed]

i think the current supplied by the source is not enough to drive the motor...

---------- Post added at 00:55 ---------- Previous post was at 00:53 ----------

that is why potential drops when motors connected..

 

[tpetar]

i think the current supplied by the source is not enough to drive the motor...

---------- Post added at 00:55 ---------- Previous post was at 00:53 ----------

that is why potential drops when motors connected..

I think that will work on AA or AAA battery, he say that is motor from toy I understund like that, maybe he calls some CNC machine toy. :-D