 This week's Eye on MPI for the CNK, ENC Optical Rotary Encoder. I always love to show people how to make their products more reliable. One of the things about doing Maker Electronics is I get to work with a lot of low cost components, but that makes me very well aware of what the limitations are of low cost components and when you want to step it up and use something a little nicer. This week's product is a very beautiful photo of the Optical Encoder with a little JSTSH connector as well. This is a rotary encoder, there's I think a 16 and a 24 pulse per rotation version and they use an optical sensor inside instead of a mechanical sensor. This makes it really good for the typical applications like automotive, industrial, test equipment and medical equipment. I think these are actually pretty good examples of when you want to use an optical encoder because I actually have my old tech scope that I got, now it's 15, 20 years ago, but the rotary encoder on it has gotten really flaky and the rotary encoder is the one that you may use, the channel one, zoom one, so it actually really makes it kind of sad to use the oscilloscope because this rotary encoder is busted because it's a mechanical rotary encoder and not an optical one. And so if you're basically, if you're working on something that's going to be like more than a thousand bucks, go with an optical encoder and not a mechanical one because you don't want to have like your very nice industrial or medical or test equipment product fail because of like a $2 mechanical component going bad. So a lot of people know rotary encoders, they kind of, they've been around for a bit but like I think the iPod classic is when a lot of people think of, when they think of rotary encoders and even have a click wheel encoder that I can show because it's a really good way to understand how rotary encoders function. The most common rotary encoders people tend to use are sort of the PAK 11 style. These are five, five or six pin mechanical rotary encoders. They're very inexpensive. They're like a dollar or two. They solder directly into the PCB. They have a little D-shaft knob and the way they work is as you twist them, the common pin gets connected, disconnected from the two side pins in a gray code and by keeping track of these pulses you can tell whether it's going forward or backwards and how many times it's been clicked. Oh sorry, can you go back one? So actually let me go to the overhead because this is where I was going to do my overhead. Show off. This is your standard PAK 11 type encoder. So you've got the shaft and the nice thing is unlike a potentiometer it goes all the way around with about 20-ish pulses, clicky detents per rotation. So these are often actually, you'll probably have one on your stereo or in your car or any other device where you have to scroll through something because you can rotate kind of forever and it's good for, you know, you can go one detent at a time to slow down or you know, mechanically you can kind of spin it very fast to scroll down quickly through a list. And like I mentioned, you know, these two pins are for the button, there's a little push button. But the whirlwind encoder part that people are familiar with is this three pin set up here where these two pins connect and disconnect from the center pin as it rotates. So that's all good and everything. And this is a click wheel breakout that we have and so, you know, this rotates and clicks around and I moved it so you could see what's going on. Inside there's this little, you know, leaf spring contact. And you can see it's got these little like touch pads like bendy parts that come down. And as this rotates you see there's a little pattern in cut into the bottom contacts and as this rotates it connects and disconnects and like that connection disconnection is how it can count the rotations, which is wonderful, right? But here's the problem and here's also why the touch wheel, the click wheel isn't used now it's turned into a capacitive wheel on the iPod is these little copper contacts, you know, they're rated for, you know, let's say they're really good quality, they're rated for oh, you know, 500,000, maybe a million, you know, contacts. That's a lot for a button. You don't usually press a button that many times but it's really easy to spin a rotary encoder around a lot and every time you rotate it that's 24 times two contacts so it's like 50 contact rotations. Let's say it's rotated 10 times a day because it's something that's being used often, you do the math and I did the math, it's basically three to five years you're likely to have a contact failure. And again it's a downer especially if it's a solder in type because to rework these is a real pain like you have to desolder and it's not easy. This one even had a mechanical tabs that I removed to make this breadboard friendly but it's like it's a reworked job. It's not something that you can use or service, it's not even a service center job you have to usually send it to an expert who can desolder and repair which is why I've been, you know, I've been waiting around to fix my, the rotary encoder of my oscilloscope. So it's nice about the optical encoders is it doesn't have that mechanical part because this is a common thing if you have old stuff with rotary encoders even if there's no dust that got into it the contacts will eventually fail. With an optical encoder it uses an LED into sensors or a sensor into LEDs instead. So there's no contact failure so they're much, much more durable like you don't have to worry about 50,000, 100,000 rotations I mean it's going to wear out like the mechanical bumps before anything electrical fails inside and in addition this has a user replaceable or at least service center replaceable GSTSH component you can plug it in and unplug it very easily to swap out the component which is what this part is. So just be aware you'll need to get a separate cable for this to plug it in. They suggest, you know, this is the part number and Digikey has the cable in stock you can get the cable and then you can have it plug into your setup. So these are very nice they're not going to fail on you after a couple years. Definitely for automotive, for medical, for test equipment, anything that's like if you don't want to have to deal with them sending it in for repair after three to five years and a lot of products that are at the higher end do have service contracts or people expect quality if you're buying a $4,000 oscilloscope you want it to last a long time and it's a real bummer if it fails because of a cheap rotary encoder. So get an optical encoder they're very nice they work exactly the same and they won't fail on you. So check out the C&K part in stock at Digikey.