Rotary encoder how does it work

When the disk starts rotating, pin A clock and pin B data lines make contact with pin C the electrically charged pad. This further creates square wave output signals as shown in the above figure. These output waves can also be used to find the angular position by counting the number of pulses of the signal.

The positioning of pin A and pin B is in such a way that it makes the shaft turn clockwise or anti-clockwise and based on the direction of the shaft the travel direction is determined. Check out the diagram for a simplified explanation of the working and classification of the rotary encoder:. We provide Hengstler incremental rotary encoder for robust heavy-duty products.

This encoder interrupts a beam of light from a light-emitting diode which determines the number of lines in resolution. The information is then available as a signal at the encoder output. The incremental rotary encoder can provide 10, pulses per revolution. For more information and technical specification of various types of incremental rotary encoder check out this page. The Hengstler absolute rotary encoder are innovative engineering and easy to operate.

This sophisticated piece of engineering is in a position to provide accurate data for motor feedback and automation. So far I have been able to use it via the serial port. I was originally going to use a compiled robot basic app but I wanted a stand-alone set up, preferably battery powered. What came to mind was using a rotary encoder to set the frequency. You have exactly the code I was looking for, thank you. I copied yours and it compiled without error.

When I get the encoders I will integrate your code into mine. I am probably going to use a separate push button since the encoders I am getting do not have an integral switch. The DDS produces a stable signal up to 40 MHz and will make a nice lab bench signal source to compliment my home brew function generator.

Once my project is done I will be more than happy to share my design with you and intend to attribute you in my final code.

Hi, thanks for your great work…I am now working on a project using rotary encoder with LCD display of the angle. Have I have your full schematic diagram of Example 2? Thank you. Do you have any idea of changing the code for 28BYJ motor? Hi Dejan, I am Interested and wanna to build this project, could you please given me the details of schematic and modules there are used.

Well everything is already explained. You can figure out how to connect the encoder from this tutorial and if you check my Stepper Motor Control tutorial you can find the circuit schematics for connecting the driver and the stepper motor. Great project, really enjoyed it!

Was it based on the ppr? My increments are always 2 instead of 1. I also added a couple of circuitry to eliminate the debounce but no way. It could be that the encoder that Dejan was using had only 2 transitions per detent and yours has 4? As you turn the knob, the 2 pin states go 00, 10, 11, 01, etc. Some encoders have the detents when the pins are at 11 and others when it is at Yours might be set to 11 in a detent, not 00, but the principle is the same.

You will have to hack this code a little to make it ignore the extra step. Great project almost what I need. Is it possible that the last position of the motor say 68 degrees is remembered by the arduino?

I do not think anyone can make this as the ButtonPin goes nowhere. A circuit diagram is needed as we all use different stepper drivers. Best is to write this in Instructables.

At first, I was excited, but now after 4 hours I only got a headache. As for the stepper example, you can find a circuit schematics on my detailed tutorial for the A driver. I think there is a small bug in the first code example. This means that one rotary encoder step will make two changes to counter. I agree. Counter changes twice for one step of shaft if you use the condition aState! Hi I am from Argentina. Great project!! I followed your steps and it works.

Although I have a problem! If I turn it slow, it does well the counter, but if I do a quick turn, it is uncontrolled and repeats steps! I used an encoder from an epson printer. Could it be because the encoder has a lot of resolution? Will it be able to work with this Encoder? From already thank you very much!!

Greetings from Argentina!! So you miss out 11 to 10, 00 to 01, 01 to 00 and 10 to To get the full resolution, you have to check every change. This works really great if you turn the rotary encoder at a normal speed. But if you turn it too fast or you do other stuff in your loop that takes longer time you will miss a step and it will jump from 11 to 00 or from 10 to But you can counter that by checking, which direction it was turned before and increasing or decreasing the counter accordingly by 2.

Or you can use interrupts instead of checking the state of the pins in the loop to ensure that no step is missed. A clearer, yet more efficient way to get the full resolution of the encoder, is this. Your tutorial is very helpful to me. But I need a very precise motor to get 1 degree per step. Do you have an idea of how to achieve it? So have I will to use a reduction to achieve this? Well maybe you could use microstepping in order to increase the resolution of the motor, or as you said use additional gear box with an output ratio of 1.

Hi Dejan, Thank you for such a great tutorials. Thank you for sharing your knowledge and make a better world. Eng Apache. Thank you Sir. You helped me a lot. CLK Output A is the primary output pulse for determining the amount of rotation.

Connections are fairly simple. Finally, connect the SW pin to a digital pin 4. The following sketch detects when the encoder is being rotated, determines which direction it is being rotated and whether or not the button is being pushed. If the rotation being reported is the opposite of what you expect, try swapping the CLK and DT lines.

Next, a few integers are defined. The counter variable represents the count that will be modified each time that the knob is rotated one detent click. A string called currentDir will be used when printing the current direction of rotation on the serial monitor. Now in the Setup section, we first define the connections to the encoder as inputs, then we enable the input pullup resistor on SW pin.

We also setup the serial monitor. If they are different then it means that the knob has turned and a pulse has occurred.

We also check if the value of currentStateCLK is 1 in order to react to only one state change to avoid double count. Inside the if statement we determine the direction of rotation. To do this we simply read the DT pin on the encoder module and compare it to the current state of the CLK pin. If they are different, it means that the knob is rotated counterclockwise. If the two values are the same, it means that the knob is rotated clockwise. Next comes the logic to read and debounce the push button switch.

To determine when such changes occur, we can continuously poll them like we did in our previous sketch.