[SOLVED] motor connected to microcontroller

[Disha Karnataki]

i have interfaced remote control to microcontroller. everything is working fine the protocol is decoded correctly and code for each key is displayed properly on the leds.
now i have connected 3 relays the o/p of relay are:
1st relay has:bulb
2nd & 3rd relay have 12v dc motor as shown here:**broken link removed**
and the relay board is as shown:http://www.amazon.in/CHANNEL-ULN200...-ARDUINO/dp/B00LMWSECG?tag=googinhydr18418-21
now i have written a program that is:
when key 1 is pressed bulb should on.
when key 2 pressed a motor should on
& similarly to the third one.
ok i wrote the code & pressed key 1 bulb switched on.
then i pressed key 2 the relay started flickering(i.e it switched on & off continuously & was not stable)
same happened to the 3rd one also.(wherever motor was connected)
Then i interchanged the position of a motor with the bulb connected to relays then too same effect.
but after i removed motors from the relays,the relays switched on properly without any disturbances.
As there were no diodes across the motors i placed diodes across them the flicker continued but, it was much reduced than before.
now how do i solve this problem of flicker? :???: i want continuous stable o/p for motors(they should be either on or off continuously)

 

[horace1]

could you be overloading the power supply or getting noise on the power lines when the motors switch on?

 

[Disha Karnataki]

but, i use 12v,2a adapter and to ensure i am not overloading the supply i removed all the loads and connected only one motor then too same effect.

 

[horace1]

but, i use 12v,2a adapter and to ensure i am not overloading the supply i removed all the loads and connected only one motor then too same effect.

I note from the motor specification
**broken link removed**
that they are rated 3 to 9V you are applying 12volts - have you
1. tried a 9V power supply
2. used an osciolloscope to look at the power rails to see if you are getting noise

does the microcontroller which controls the relays have a seperate power supply?

 

[nick703]

which micro controller u used ?
horace1 is right your motor voltage rating is 3 to 9v . and also post your schematic to find your problem.

 

[Disha Karnataki]

now i have connected seperate power supply to each of the motors & works well.
thank u