Adventures in Science: How to Use Rotary Encoders 

yeah i noticed this one too. thanks for mentioning it. a bit confused but overall the whole video explanation is very clear.

Use a good quality encoder. Otherwise go for stepper motor. I personally tried all three. Servo (real rc servo only rotate 180° , 360° servo doesn't have feedback so there just plain dc motors with speed control) , dc motor with encoders and stepper.

Francisco José Campos Arizmendi you buy a motor with shafts out both sides.

Hall effect sensor is available on e.g. banggood, eBay or AliExpress. Did you find any magnetic encoder disks?

Usually encoders use two sensors that are offset at a multiple of 9/10 of a step, same way as in calipers. In this way precision is increased tenfold.

Not exactly my point. I'm talking about integers or booleans set or reset every time on every action. Then you will have a "source" for many conditions after.

You can however do not that these encoders are very inefficient.

Ncheeta Morero read about H bridges. 2 digital output pins for every wheel determine the direction of rotation + 1 pwm output (again, 1 for each wheel) to control the speed of that wheel. This should explain it!

For each motor there are two pins and one pwm pin. For two motors that's 6 pins. There is one standby pin that has to be held high for motor driver to work. And then there are one pin each for encoder output.( If u r using quadrature encoders, then there are 2pins each for a motor). So in total there are 6+1+1+1=9 pins.

Depends on the hall effect sensor and the electronics detecting the pulses.

Bastian Springer you can take cheap standard optical encoders, the result will be the same

@@user-os1xg1rh4c I'm quite space limited. That's why I was looking for magnetic discs with a hall sensor. But I ordered the ones from Pololu by now and they work perfectly

Yes, if you watch the video at around 7:53 (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-oLBYHbLO8W0.htmlm53s), you'll see that I set the robot to measure millimeters and stop after it's traveled 1000 mm. For a human-scale example, measuring wheels (like this one www.amazon.com/TR-Industrial-Collapsible-Measuring-Yellow/dp/B01018D7MS/ref=lp_3753421_1_1) work on the same principle. As you walk with it on the ground, a device counts the number of rotations and by knowing the circumference of the wheel, you can figure out how far you've walked with it.

Roinaldo Pho it most probably is because it uses and 8 bit data system and can’t handle more than +/- 255.

@@roguepathfinder2477 microcontroller has an 8bit ADC.

zeus 0101 good to know! And i was almost right, that’s a win in my book.

A linear optical encoder (if it's an inkjet)

Many of the last generation of mass production VCR's use them as well. I've taken several from old TV's that had integrated VCR's. They are usually mounted on stands that are easier to incorporate in other hacked designs too. You can also grab the LED's from a remote control and the IR receiver to make your own encoder, although you need the simple kind. A lot of newer IR receivers have integrated IC's in them and that can complicate the design.

The diameter might decrease slightly if your wheels are particularly squishy. A gray code is used to correct the potential issue of an absolute encoder counting false states between two real states (en.wikipedia.org/wiki/Rotary_encoder#Ways_of_encoding_shaft_position).

Well, I'm hoping that the video can teach someone about encoders, and it might entice them to look at our store. We were all beginners at one point :)