Introduction: Drive Servos With a 555 Timer IC

This instructable provides a walk through of a basic servo driver using a 555 IC chip 5 resistors a transistor and 2 capacitors.  The idea is simple, use 2 switches to control the motion of the servo. Note this circuit is based on a servo tester circuit found on the Internet. We built this with parts from Jameco Electronics at an instructables build night at Arch Reactor Hackerspace. Thanks Jameco!

Step 1: The Circuit

This is a diagram of what we are building. This and many other 555 circuits can be found on www.555-timer-circuits.com

Step 2: What You Need

555 IC 68k resistor 4.7k resistor 33k resistor 10k resistor 1k resistor 2 - 100n capacitors bc547 transistor 2 momentary push buttons a servo a 6v power supply jumper wires. LOTSOf them.

Step 3: Wiring

wire the circuit as in this image. Be sure to lookup your transistor and match emitter, collector, and base as in the circuit diagram. Do not hook the power up until after it is wired. Refer back to the circuit diagram as needed to clarify wiring questions.

Step 4: Add Power

Connect power to the red and black rails and press one of the buttons. You should see the servo move in response to the button press.

Step 5: How Crowded Can It Get?

It's a good idea a breadboard this out and simplify afterwards. It's a nice quick project to get you started on servos.

Step 6: Optional

A meter is optional but can really go a long way in helping you resolve issues. I highly recommend getting one for any of you circuit projects.

Comments

author
musaab123 (author)2017-02-20

Hi, can you tell us how can we have control over the vitess of the motor using this circuit??

author
Shashidhary (author)2016-06-30

I made the circuit but It works only in forward bias. I used all the same components and a 5 v DC power supply

author
JAYK0 (author)2014-11-14

Hey I made this but instead of a 47k resistor I used a 10k potetiomiter

author
luiz.magalhaes.754 (author)JAYK02014-11-21

Hey, could you send me a pic of what you've done I cant get it to work. thanks

author
gfetters (author)2014-11-04

I used an 180 degree servo but this would work with a continuous servo. two 100nf capacitors.

author
EarthShacker (author)2014-11-03

what type servo motor did you use? i mean 180 degree servo motor angle or continous servo motor? the list of component of the capacitor is 2 100nF or 1 100nF and 1 10nF?

author
EarthShacker (author)2014-11-03

what type servo motor did you use? i mean 180 degree servo motor angle or continous servo motor? the list of component of the capacitor is 2 100nF or 1 100nF and 1 10nF?

author
EarthShacker (author)2014-11-03

what type servo motor did you use? i mean 180 degree servo motor angle or continous servo motor? the list of component of the capacitor is 2 100nF or 1 100nF and 1 10nF?

author
OhYeahThatGuy81 (author)2014-09-25

Just out of curiosity, what frequency is the PWM being driven at? Roughly 10kHz?

author
ferjanyen (author)2013-10-02

Nice project, please let me know when you got the wi-fi sorted. Thanks.

author
wiredcav (author)2013-09-19

Very nice project. I presume you're sending two PWM signals corresponding to two servo positions - yes? I would think I could replace the two resistors and switches with a potentiometer that would allow me to drive the servo to any position. Is this right?

Thanks for a cool project.

author
gfetters (author)wiredcav2013-09-20

You are correct. A potentiometer is an excellent idea as a replacement for the 2 push buttons. I am thinking of adding a WiFly to this so I can control the Servo via the internet.

author
BJack042000 (author)gfetters2013-09-29

THAT WOULD BE AWSOME IF YOU COULD ADD WIFI CONTROL

author
tcarney57 (author)2013-09-19

Very nice. Are the resistor values chosen such that the servo turns faster forward than in reverse?

author
gfetters (author)tcarney572013-09-20

No it should be the same in either direction.

author
Poppy Ann (author)2013-09-20

I was trying to do this circuit a couple of years ago as i wanted to use a brush-less model motor and propeller as a fan on my boat but when i found out i can buy a servo tester for $4.50 i just used them instead as the cost of 12 volt fans was around $15 for a cheep car one or $55 for a boat one and they only last around a year as the brushes always wear out but the model motors last forever and use less power to move more air plus i can control how fast they run which is great so they do not make as much noise as i leave some of them running all night.

author
gfetters (author)Poppy Ann2013-09-20

Excellent Idea.

author
EDLITE (author)2013-09-19

You have gone to quite a bit of trouble when you can buy a nice Turnigy servo tester at Hobby King for 6 bucks! http://www.hobbyking.com/hobbyking/store/__8296__Turnigy_Servo_Tester.html

author
gfetters (author)EDLITE2013-09-20

Its nice to build once in a while instead of buy. I could have easily done this with an arduino too.

author
ginodisimone (author)2013-09-19

a great adaptable circuit for solar tracking (improved solar panel efficiency) or astronomical tracking. thanks.

author
askjerry (author)2013-09-19

Our robot group was looking for something simple/kool to do... I think this would be a good project for some of the new folks. thanks! great job!

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