Analog Feedback Servo Motor - Improved Servo Performance

Today we are going to explore the use of a special type of servo motor - an Analog Feedback Servo Motor.

We have used servo motors in many of our projects and tutorials, and for many good reasons. When you need a method of precisely positioning something a servo motor is an expensive and effective solution.

The small analog servo motors we have used before have three leads - power, ground, and a control signal. The latter is a connection that accepts a PWM signal and uses it to position the motor shaft to a specific position. And, in most cases, this works great.

But sometimes we need to know the exact position of the motor shaft, which may or may not correspond to the position we asked it to move to. External forces can move the shaft into another position, or the shaft may still be moving into position.

The Analog Feedback Servo Motor is a solution to this problem. This is essentially a standard servo motor that has a connection brought out from its internal feedback potentiometer. The feedback connection allows you to monitor the shaft position in “real-time”, so you always know exactly where it is.

An interesting benefit of this type of servo motor is that it can also be used as an input device. This is great for projects like a robot arm, where you can manually guide the arm through some specific movements and then play them back. Essentially this is a servo system that can memorize and repeat its movements.

I’ll be working with the S1213 Analog Feedback Servo Motor today. I’ll show you how to calibrate it, and I’ll also run a net sketch from Adafruit that can memorize servo movements and play them back.

Here is what we will cover today:

00:00 - Introduction
04:03 - Analog Feedback Servo Motor
07:54 - Calibrating the Servo Motor
13:44 - Servo Memory Sketch

You can actually modify a standard servo motor to become an analog feedback servo motor, but it’s a lot easier just to buy one - they are not that much more expensive than a regular servo.

Hopefully, this video and the accompanying article will give you some inspiration to start using this unique component in your own designs. If you want to chat about this jump onto the DroneBot Workshop forums and let us know what you think!

[MrBanzoid]

Yet another brilliant video! Production, sound and content are superb, as well as your teaching style. Thanks very much.

[bobyla]

16:00 saying is
pinMode(aPin, INPUT) + digitalWrite(aPin, HIGH) = pinMode(aPin, INPUT_PULLUP)
this lead to activating the internal pull-up resistor

If a digital pin is configured as an INPUT, digitalWrite() will enable (HIGH) or disable (LOW) the internal pullup on the input pin

[ElChocoLoco]

Just a quick note to say thank you for all the videos. I have learned SO MUCH from them.

[aldoperez]

Best channel on ever, well explain and very professional thanks for your time

[RelentlessHomesteading]

Never thought about using a servo as input - very cool. Thks

[oliverimperial]

loving your tool wall! awesome vids, thanks!

[zxscript]

Thank you for the great video!
What is really annoying about casual servos is when Arduino starts we can only guess the position of a servo, but do not know it, so we usually need to reset it to some position, which happens pretty fast and looks like servo is about to kill itself with a sudden movement.
(Hi from Ukraine!)

[braddixon]

New to your channel, and have enjoyed all that you do. Your vids are really clear and easy to follow. thanks for posting great content.

[woolfy]

That's cool. I don't have a use for it but, it looks something to play around with.

[yawarsaeed]

Awesome 👍
Thanks for sharing such an amazing tutorial on servo.

[andrewbarnard]

Great vid, wish you would of opened the servo up and shown the internal difference between that one and a standard, would of been fun to watch you mod a standard servo to have this function also

[andymouse]

This is great!...now to teach it to weld for me.

[glennfelpel]

Outstanding video in every way,  Thank  you for producing it.

[mcboomsauce]

got dang mang
this is a very well put video sir!

[deankay]

I am building a heater control actuator and circuit for a 55 year old pickup. A $5-$20 actuator that’s strong is used in auto’s that fall into this category of “Analog Feedback Actuators” tutorial you shown, for heater door control.The actuators have a potentiometer built in, gear driven by the motor. So in a salvage yard, this is a 5 pin type. Cut the wires to get a connector.
Question: Is the EEPROM on the Arduino or motor controller? After the limited movement is recorded, a linear potentiometer on the dash can control the heater door position by moving the “Heat Lever” to half for example. If 0-255 was the range, that request would open to 1/2 or 128 by the dash controls. This must be how auto engineers design the “Logic” board for the HVAC module. I don’t have social media but maybe I can follow this link to sign up for discussion on this event. I really don’t have a laptop to write code, nor buy an Arduino, motor controller if so simple is available.
Thanks kindly for help on this 4 yr old subject.

[noweare]

This was a very cool video, thank you

[mvmcali]

how do you have such a clean workbench, you are making the rest of us look bad !

[TheUnofficialMaker]

cool, this will make a great annimation for props,

[automationtechnology]

very inspiring video, thank you Sir !

[Ronnie.Ericsson]

Great! Are there servos with negligible resistance to turning by hand? I’m thinking motorized volume control.