 Welcome to the show. It's me JP. It's time for John Park's workshop. We have arrived. It is Thursday And I'm super excited about today's show. It's gonna be a bit of a deep dive into some audio cassette tape silliness and Let me pause the little preview there so I don't see an echo of myself. Hey, stop that me. There we go Yeah, so we're gonna dive into some cassette stuff in honor of that I wore my cool amulets t-shirt amulets is a music artist who does a lot of cool cassette manipulation Go look him up What else to say? Thanks for stopping by if you're over in the YouTube chat. Hello I see you over there as well as our discord and I bring up our discord because if you are over on Twitch or one of the Other platforms Facebook, you don't know where the people are where the chat is it's happening over on our discord It's just to consolidate things and so that way I don't have seven chat windows going at once Hi, everyone. Hi see Grover So I apologize in advance see Grover this this episode is gonna Drive you bonkers with all of the bad things I'm gonna do to cassette tapes as a as an audio engineer type of person It'll make you shudder probably But all in the name of good fun and science I think so What else have we got going on? I'm excited to have somewhat permanently posted my Sony CRT over there with the video shank nub running the clock running the vaporwave clock I don't know if I'll keep that forever. It's a bit of real estate And also sometimes it's a pain to actually have a clock in your video frame if you want to edit stuff But I don't know it's fun. It's cool looking What else is happening? So We have a jobs board you may have heard of it It's at jobs dot Adafruit comm and if you head on over there You can find people looking for People to hire there's contract freelance full-time internship part-time remote and volunteer work all of those are valid Things to post it's free to post. You don't need anything other than an email Address in an account with Adafruit you submit and lady Ada and Phil take a look and post all the good stuff So it's vetted And these are all positions that people are looking to hire for and you can also click up here in the available for hire section I think I'm not logged in right now when you're logged in you can see people's Resumes and CVs and other important information about them. So that's at jobs dot Adafruit comm Excuse me a little something in my throat. I'm gonna grab a sip of water Hi, Johnny Bergdahl over in the YouTube chat. Good evening to you Let's see. What else is going on? Did you know on Tuesdays? I've got this show which is JP's product pick of the week and on it I like to take a product Slice its price in half not always, but usually 50% off show you how it works do some demos and Let you enjoy it for 15 minutes or so throw it in your cart buy it no coupon code necessary and get up to 10 of Them and I like to do little demos that I then excerpt down to one minute. So here was This week's product pick. It's that joy feather wing that I love so dearly and here is my little recap It is the joy feather wing, this is a PSP style analog joystick So it's a potentiometer that goes from zero to ten twenty three zero to ten twenty three for X and Y axis and It also has the four AB XY buttons. It also has a select button at the top. This is the original seesaw board a little seesaw chip that is taking care of finding out what's going on on the board in this case Collecting the analog input and those five button presses and then sending all that info over I squared C What I'd said do is make a little game console using the feather wing and you can see there It's just connected over I squared C's thumbstick there to rotate the little ship and Then I can use the B button to thrust get away And then I can do the old death blossom Fire off. I think a maximum of five shots. It is the joy feather wing That's right. It sure is. How many of you went and got some I know there's some there's some cool projects that people have have done out there some good things to go and check out. I Really am interested. I mentioned it the one where someone put two of them side by side one flipped like this and it's exactly the We not we the Nintendo switch layout with those two little Switch controllers that slide off the size of the joy cons. Hey joy feather wing joy con Kind of cool. And in fact the Ruiz brothers just did a neat little Project using one of our displays and building a 3d printed switch style ratio controller, so Check it out What else is going on? Hey, this is a good time to do Something I like to do each week. It is the circuit Python parsec All right, I'm back. I disappeared there for a second So for the circuit Python parsec to do I won't today. Let's try that again for the circuit Python parsec today I want to show how you can use a random integer and a random float With our random library to play some simple tones that equate a sort of bleepie bleepie The computer is thinking type of sound. This is in my series of computers are thinking projects So look how simple this code is first of all, let's do an audio demo. I've got it hooked up and running I'm just gonna enable the speaker. All right. That's probably enough of that I'll pause that and so the way we're getting those cool little bleepie sounds is Importing the board library and simple IO simple IO is going to be used with this simple IO tone Which just requires a frequency and a duration so you'll notice I don't even need to import time Then I'm importing two things from the random library Rand range which we use to Set a random range of integers and uniform which is used to give us a uniform Distribution from zero to one of a float or a decimal number all I do in my main loop I set the Frequency to be a random range in this case I'm using anywhere from 40 Hertz to about 1200 Hertz And then the duration is anywhere from 0.2 seconds to 0.125 seconds Then every time the simple IO tone is called it plays over the pin a zero analog pin Whatever that frequency and duration are and then it repeats that over and over again, so Play that again And you can see here if I raise the pitch. Let's say we'll get some higher Now it's going a little bit higher. I can also set some longer durations. Let's say half second ones so that's hanging out for half a second on some of those tones and That is how you can use random range and uniform to play some really simple tones using the simple IO tone library and make your computer Think and that is your circuit Python parsec. All right So now I think it's a good time to get into some of the aforementioned cassette tape shenanigans so First of all what I want to do is a bit of a gear report on a item and this is called the human controlled tape transport The reason I'm bringing this up is it's a really fundamental cassette playback device because all it has is the read head of a cassette the amplifier part of the circuit and then a Manual control to turn the little take-up reel on a cassette tape so I'm going to head over to my workbench and Let me describe this the there's a lot of stuff. You're seeing there The item in the center that's silver looks like it's in a stompbox sort of this is the human controlled tape transport right here And I'll head over there and make it play but essentially I'm going to feed a cassette into it And you can use a regular cassette or a specially prepared cassette tape loop I'll show you a bit with both of them and then as you turn you're simply moving the tape across the head in an incredibly uneven manner and you know one of the keys with a cassette playback to sound good is it has to be locked into a Speed that is consistent. Otherwise you get variations in frequency. We're gonna get lots of those because this is a manual Tape transport. So let me head over there and we'll take a look at Where's the right camera there it is and That's the one I'm looking for. All right, let's head over there okay, so What I'll do first is Take a cassette and I will start with About this one right here Okay, so this is a mix mix cassette My wife made years and years ago and I'm feeding it into the tape transport and now the Tape itself is touching the reed head that's back here I don't know if you can see that there's not a lot of light In there, but you see a silver thing actually let me let me zoom in you might be able to All right, so there you can see there's the little tape head And this knob here is connected to a little shaft with a sort of rubber end a little bolt vinyl bolt protector Kind of end that is going to go into the take up reel here And then I'll be able to rotate the cassette to drag it across that That take up out again a little bit Okay, so I'll feed this in And then I have this running into my little blue box Mixer here so we should hear it Oh gone the wrong way So you can almost hear a little drum line there and then some garbled lyrics and things happening And actually I'm going to check the chat. Let me know I can pull it up on here. Let me know if you Can't hear at all The samples that I'm playing over here the examples that I'm playing because I want I want to make sure you can hear those So let me Open up discord on my phone here so I can see any chat and that would be really helpful if you Can let me know Let's see Do do do where is our server there you are there's live broadcast chat. Okay, so I'll keep that Keep an eye on that so let me know so I'm gonna Bump up the gain on this a little bit and do that again Sounds good there. Okay, great Okay, so you can of course add effects to that and stuff These sound much better with some delays and echoes and bit crushers and things like that attach them But that thing is really cool. Uh, and in fact, I wanted to take a second This one is the the version one of this that came out a number of years ago and they've Moved on to a version two. I just wanted to show that Since I'm talking about it here. It is by landscape FM you go to landscape f m dot com and the new version is this you can see it's got a pcb Fiberglass pcb as the enclosure now and there are a bunch of Improvements and add-ons with the main improvement is that there are now two Shafts going into both sides so you can go in both directions because the thing with a normal cassette is going Backwards on just one of the take-ups is just going to create a bunch of slack and and cause problems for you So you can't scratch that one with a with a normal cassette But anyway, this is the this is the new one you can see there It's got it's got a couple knobs on it also has like some capacitive touch things for Kill switch and some other other functionalities, which is pretty cool If we head back over here, I'll show you a little tape loop I made which allows me to Go forward and backwards. So this is Your typical cassette I'll take the one out of here Actually, this is a good one as an example so you can see With a typical cassette if I go The wrong way I'll grab a pencil here It's just going to create slack so you can see that little Little slack happening there so you can only go in the one one direction and it pulls pulls the tape across From the other reel so if instead You take a part of cassette You can make a short little looping section So you can see there I've got this little tape loop I made just by pulling apart a blank cassette Taking all of that off. So there's there's the main Amount of tape there and then you can make a little three four second loop here Depending on the playback speed The trick with these is one you've got to splice the tape so you have to use some tape splicing tape or some Some decent scotch tape if that's what you have I've never tried capton tape that but that might work pretty well too. It's pretty sticky and quite flexible and thin and The other trick with these is the amount of tension. So when a tape head Presses against the tape it pushes it into this little Felt dudad here official term You need to make enough contact there So this can't be stretched so tight that this doesn't depress in it also can't be so loose that the Take-up reel there which is just A little piece of plastic like this Let me zoom in a little closer and focus better on these things. So That on its own is quite slippery Not not a lot of friction there. So you can see on the one I made here I added a little Sort of tire around it. I super glued a rubber band a thick rubber band Which gave me some grip on the tape and it also Increased the diameter of that a little bit which I needed so now you can see If you look at the tape there either direction I go It drags across which means if you tape something on there, ideally you'll tape something like a drone sound on there to get sort of consistent sound you can pitch and go get variations in both directions without it sounding super weird like voices or drums But those are fine too I have put sort of a Droning sound on here that I recorded It has gaps in it, which is a problem. You actually don't want gaps in it because you can hit dead spots, but let's uh Let's get this going here and I just want to Figure out why this is so quiet. Why are you so quiet that I lower? My main output volume Yeah, the gain is way low So you can see I have these big gaps, which is a bad idea Um one thing too It's a little better. Uh is to mention there's a bit of slack in here and Pending on how well your tape is seated If it's a little High or a little low as it comes across the the head there you can Get a mix up of tracks. So a typical cassette has Two tracks going let's see. Does this work right now? Yeah, uh typical cassette has Stereo pair going one direction and a stereo pair going the other direction So it's actually four tracks on a tape when you flip the cassette over you're you're playing in forward Uh on the other side. It's actually like this. So I actually have a little four track here four track cassette recorder that I got back in the 90s This treats all four tracks as individual tracks. So it's like having a four track recording Set up without having a big reel-to-reel expensive thing. These were pretty cheap So if we take for example Uh, what's a good cassette for this? Is there one in here right now? Okay, this I think has My drone on it on one side and some spoken word stuff on the other. Let's see if we If we can hear that What am I doing? Let me put this in properly got distracted here I just wanted to bring up my discord again to see if you you can hear anything Yeah, thin man says sounds good here So maybe a stepper motor down the road right if you want to turn this back into machine controlled add some sort of Motor to it. So here on this one if I play So that's the side B stuff or the flipped side stuff playing because I've asked tracks three and four to play if I go And turn the first two tracks on that's something I recorded in the other direction so kind of cool that you can Grab those other tracks, but it's just to explain that that thin little piece of tape has these four Um sort of sections that are just where it writes to a stereo pair and a stereo pair going into opposing directions Um, so that's kind of a gear report right there just with this cool little human controlled tape transport. Um I bought that used off of someone on a online forum. Thank you so much for that. Uh, super cool what I want to do now is Uh Take this into the realm of a project I want to work on and so the project I want to work on is a variable speed cassette playback Using a combination of either manual control like a potentiometer Microcontroller control so using maybe a digital potentiometer And then feeding that microcontroller either midi or control voltage from a hardware synthesizer so that you can maybe Make a little droning loop or something like that or it could be could be a full cassette's worth Of one pitch. Let's say a c and then depending on your playback speeds you can pitch it into different Not quite in tune, but maybe depending on how lucky you get Frequencies, which is kind of cool This is a popular project. You'll see it out there. There's some products made just to do this and then there's a lot of hacks one piece of gear that's really popular for this is this Byron statics I think that's its name Byron statics Cassette, this is like $15 online. They're new. They're they're newly made and they're kind of cool. This has a usb Mini for power or two double a's And it has a radio a mfm radio built onto it And then it has a speaker built in a microphone So you can record right to it as well as the playback for reverse Stop and the record there you can also record directly from the radio internal radio onto the tape So it's got a bunch of features, which is pretty cool Very cheap and not a bad place to start with some hacks because it's so cheap. There are cassette players that are really great for this As far as getting in there really quickly and easily and that's because there are cassette players that have variable speed playback Already built into them and these kind of fall into two categories really one is dictation Machines and it could be cassette sized could be larger size But dictation cassettes will have variable speed just so that someone who is transcribing it can slow it down or speed it up After someone has recorded notes into it And then there are also ones that are made for just adjusting the pitch of music that you're practicing to I don't know of any examples other than this one, which is the Ebonaise rock and play Stereo cassette player for guitar rp 200 and I think they had another model of this and maybe some other brands did But even as who makes guitars and amps and things they made this And it's a pretty cool gadget in its Own right I think I've shown it on the show a couple years ago when I got it at a thrift store for I think five dollars or something like that but this has if you can see here a tape speed control Switch Lower that a little bit So this switch is between normal and half speed and then you have this pitch control Which is a potentiometer that will give you more fine-tuned changes So if you're let's say your band is playing it in a certain key You might be able to practice to it in that key even if the original wasn't written in that key and then it also has Two guitar or line inputs so you can or instrument inputs So you can plug in a guitar at a base or something like that Hear them in your headphones along with the tape mix between those got a little three channel mixer there And it even has a two headphone out so two people can be using it They thought everything and it also has some effects on the Input so you can add a chorus or a chorus and a distortion, which is pretty wild So what I want to do is I'll put in My little droning cassette Is that the one I want? No, I want this one here Move this out of the way a little bit And zoom out. So this is just on battery power right now. So I'll take that and I pulled the door off just to make it easier to see what's going on and I'm gonna take One of the headphone outs and go into my little mixer there. So Set it like this Okay, so this is a little droning synth thing I recorded So you can see here this is just using this pitch control And you can see there if we aren't sliding Between those pitches and instead if we could jump there, I was just trying to jump really quickly between some Some settings you could play it like sort of melotron, which is a an old keyboard that had essentially a tape loop per key So getting rid of that sort of sliding thing that would be the idea behind using something like a digital potentiometer Where you could just go directly to a different resistance level for the speed controller on the motor And get it to play back the way you want it to without all that slide. This one does have that Full half speed playback. So I'll go back to Normal So that's half speed All right, so that's the idea. That's what we want to try to replicate Instead of this is just a lucky find. They don't really make these anymore. I had to replace The main belt in it. It had just turned to goo, which is kind of the problem if you want to get used Walkman Generic term I'll use it as on ebay or other places It's not a bad idea. Look for ones that say they are tested and works because if not you will have a job Ahead of you of getting inside. Sometimes it's a pain to get where you need to get Sometimes you have to take a lot of things apart to get a new belt on there You also have to buy a pack of cassette belts. You don't want to try to use Hair bands or rubber bands or anything. You got to kind of get the right right stuff Rubber bands will again just kind of give you trouble and stretch and turn into goo again So rather than that the idea is Start from this one even though this one wasn't built to do any of the speed control It is possible to add different resistance levels to the the dc motor to get some primitive control. So Let's first of all just plug this one in and check out how it sounds I guess i'll steal Is that the one I want? Oh, this red one. Okay. I'll steal this one here and I'm going to plug that into phones So let's just test this one out Uh, we can put our same actually let's take this little tape loop I made so you can hear it better what it actually actually does I'll see how well that works Okay, some players won't like a tape loop. I'm going to flip it over. Sometimes that fixes it Uh, it senses a problem with the tension and it stops so it doesn't eat your tape Let's try it this way Okay, yeah, it's not good. This one's not going to like like this loop. Um, it might be possible to overcome that But I'll use a regular cassette, which is this one here Let's just adjust the amount of gain and volume I'm giving it in the first place Okay, uh So there it is a normal operation. We'll go ahead and rewind Okay, good. So now let's take it apart and have a look, uh, and I went I just Got inside of here a little bit earlier to Take a look and see if I could find uh based on some projects. I looked up online. This one's really popular You'll you'll see people selling them on etsy already modified. You'll see some some Nice close-up photos of mods people have done already and I'll show you a few of those in a second What what I'll do is I'll go ahead and pull out my batteries first And then there's just four screws on here and a little uh pair of latches to Overcome with a little spudger guitar pick kind of thing. So I've already I've only put two of these screws back in so I'll go ahead and Take those out and let me go ahead and zoom in here should do Uh, yes, he grover said in the chat sometimes both hubs need to turn Otherwise it thinks it's at the end of the tape. That's a good point And I I have not done much, uh cassette loop building some people. I know do it with a pair of uh Rollers or take up hubs still in there whatever their name is. Uh, I think that may help All right, so to get this apart it kind of Hinges off of here a little bit, but there is uh A pair of clips to defeat down at the bottom here. So I'm just going to take this little guy and Click past one Click past the other now it's loose enough to lift up and over the little volume knob there that was caught on All right, so now that we're inside, let me see. Can I get any closer? That's about as close as I can get We can put some batteries back in it And yeah, one of the wild things about this is such a coming together of modern and ancient where you've got a usb micro in here for power, and I'm assuming some little voltage regulator here to convert the five volts down to three that it runs off of and uh so Just looking at one of the guides I saw online um I'll Yeah, I'll let this play. I might actually go forward to some of the voice playback That'll be easier to hear it in so let me let me fast forward this a couple minutes I just recorded a couple minutes of that drone on there So this will be a spoken word audio book kind of thing Further this is not a fast the fast forward and rewind are not super fast on that compared to my little task cam here some more That is and you said everything's changing used to be in the old days The media image roughly corresponded to reality, but now it's all reversed The media image is so there's a ground here and a existing resistor on the motor excitement So now day-to-day life is false and the media image is true Sometimes I look around my living room The most real thing in the room is the television. It's bright and vivid the rest of my life looks a drag There we go. Oh, sorry. My head was in the right turn the damn thing off That does it every time Get my life back Basically continue to pet the dog She saw a headlight from the darkening night swinging around the corner and come up the street toward them She got to her feet walked to the current Okay, so uh that is Sort of the basic foundation of figuring out, okay, where are we going to go in and connect up to um Be able to adjust this motor control you could do it by following the motor and seeing where it's uh plugged in I didn't have to someone had done this exact one already So I I didn't need to explore but you could also approach it kind of like circuit bending where you Find a ground and then just start prodding around bypassing resistors and or changing the resistance value To see what happens. So That's a start what I think i'm going to use uh to do it is our Little linear digital potentiometer. Uh, and in fact, this is a good time to show you, uh, this was a Project that liz showed me uh that she found online And It is This one from guide to pont. You can see it looks a little familiar. Uh, and what he did is really neat, uh grabbed the voltage off of the USB so I think it's still powering the cassette player from usb power and powering maybe even data Uh to the little cutie pie in here, which is great and there's that uh, Dallas semiconductor 3502 i-squared c potentiometer. So that is connected up to those points ground and then the two Uh, there's there's the wiper ground and voltage. I'm presuming and then digitally changing that position of that wiper, uh to adjust the The motor speed so that uh, you can check that out just on twitter guide to pont gvy underscore dvpont Has some info about that if you also look around. I mentioned, uh, amulets. This is amulets music.com and there's a lot of great info about cassette tape manipulation making your own Tape loops and so on and I Saw here. This is someone on etsy who's just taking these and adding a little manual speed controller or control voltage input, which Is pretty cool dual cv and line ins bunch of options you can get on those that are built into it and Here's an example of someone making a full euro rack module based on a cassette transport that's been Built into this little panel. It has control voltage and gate I think in it has a speed controller on the front of it and a couple other Things so if you if you google around there's a lot of really neat Um projects that are out there using Cassette players as well as that particular Inexpensive one, which is pretty cool So let's see what else I think The plan with this will be next steps will be i'm going to take my Where did I put it? take my little digital potentiometer and A qt pi which work great together and start Coding that to be able to just do some sweeps back and forth to change change the timing Or change the the playback of the the motor speed and then look at doing some midi input So it'd be kind of cool to send midi notes to the qt pi over usb Which it then converts to different values for that potentiometer so that it plays back at different speeds And then I think a It's actually easier to set up something like midi than it would be The control voltage because a control voltage coming off of something like euro rack can be anywhere from negative to positive 10 volts So it's a little bit more circuitry needed to Bring that in and then convert that to resistance values of the digital potentiometer, but it's totally doable I'm not sure about gates because often a gate impulse could be used You could use that maybe to just do a full stop or some kind of a muting Of the player so it might be neat to have both gate and control voltage In there So let's see any questions or thoughts over in the chat. Let me know Um People are referencing the Beatles with with the uh cassette playback and and backward masking and all that for sure Uh And let's see. I also want to mention I will be out next week returning the following week So I wanted to give you a preview of this Uh, Lamor and Liz and I just talked about this yesterday So, uh, the fact that that little teal colored cassette came in less than 24 hours is kind of amazing kind of scary Uh, but I obviously I've got a lot of other tape stuff to goof around with But I'm looking forward to trying to modify that one in specific because it's nice to be able to recommend something Do a project guide where people can actually go and get this thing which may have a bunch of different names I'm not sure sometimes you'll find products that are made in one factory and get a bunch of different names put on them But uh that one I'm not sure that one may may just be one manufacturer Uh, and Liz and I will be collaborating on that. So, uh, also look out for some cool Other cassette players. Liz has a has a neat one. She just ordered that. She's looking forward to showing off I can only imagine she's going to add some colorful leds to it, which will be cool And I may pick up one of the g e There's a general electric g e um sort of Walkman with speed control built in that's really popular very available The sony ones that are super nice, but less available or more expensive But you can for 10 15 20 dollars get Some of these super popular g e ones and just look for one that works or be prepared to to swap out belts Uh, I think that is everything I wanted to Uh show you and bring up and get started today. So look forward to um Follow up on this in a couple of weeks and I think that's going to do it for today. So, uh, again, thank you everyone for stopping by Uh, that's going to do it. Thank you for it for industries on john park. This has been john park's workshop Yes, uh, sorry thin man. No show on tuesday next week. No show on thursday for me So there will not be a product pick of the week on tuesday and there will not be A, uh, workshop on thursday will be out the full week Uh, so thanks everyone for stopping by. I'll see you next time. Bye. Bye