Which relay to use in a project that controls servo motor using microcontroller?

[sramgrk]

Hello ppl,

my final yr project is to control the servo motor using micro controller, i have planned to use a relay but i am not sure which one to use. I am using ULN 2003 to drive the relay which is driven by a +12V supply but the motor that we are using is +4.8V-+6V, so which relay rating should i use?? please reply

 

[kabiru]

Re: Relay Doubt

Hi, i think u need to regulate the supply for the motor then used the 12v relay.

 

[IanP]

Re: Relay Doubt

I wonder what do you need a reley for?
There is no need for a relay, unless you intend to switch the positive side of the power going to the servo .. see attached picture ..

To operate 4-6V servo you have to step down voltage from +12 to, say +5V (using for example 7805 voltage regulator) and program a mocrocontroller to send pulses (between 1ms and 2ms every 20ms) to the servos's control wire ..

**broken link removed**

Rgds,
IanP

 

[sramgrk]

Relay Doubt

@IanP:
I need to switch off the motor and is way i had planned to use a relay. I just didn't know which pin of the relay should be considered as input and which as output because i didn't find the pin configuration anywhere. I have got a 5V relay with me which is Goodsky gs-sh-205t...how to connect this to ULN 2003??

 

[IanP]

Re: Relay Doubt

Here is info on SH - Relays:

**broken link removed**

and in particular on the GS-SH-205D:
**broken link removed**

Rgds,
IanP

 

[sramgrk]

Relay Doubt

@Ian p:
The pictures are so self-explanatory thanks a ton for ur help.

Can i connect the output of the relay to the MOSFET of a buck converter??

 

[IanP]

Re: Relay Doubt

If you mean something like in the attached cartoon, can't see any reason why not ..

Rgds,
IanP

 

[sramgrk]

Relay Doubt

@IanP: one small doubt, should i connect the output of the ATMEL 89S52 to the relay or to the gate of MOSFET?? because in the above cartoon the control circuitry is connected somewhere else. thats y this doubt

I meant what is exactly mentioned in the above cartoon, thanks a lot for that

 

[sramgrk]

Relay Doubt

Can i directly connect the output of ULN 2003 to the GATE of the MOSFET....i intend to do the same operation that a relay does with the pulse, so can i use ULN 2003 as a driver to the MOSFET?? suggestions pls