Making A Synthesiser Sequencer Out Of RELAYS Part 1

relays we're not talking about relay races we're talking about electromechanical switches actually relay and relays they sort of derive the same definition from the same situation and that is relaying something in a relay race you're relaying a baton in relays you're relaying electricity electric relays are surprisingly old they have been around since the early 1800s all of the early ones were made for a very similar purpose and that was for relaying information long distances over time these signals fade and will require boosting and amplifying again to get you know keep on going and keep on going and that's where a relay comes in so this is a relay but this is also a relay it's a it's a pretty much relay at that i'm pretty sure this relay is from some sort of rail thing some sort of railway communication or junction or something like that but regardless it's just a big relay and this relay is perfect for showing you what the heck a relay is how many times do i need to save relay so initially the relays were made to uh basically amplify signals they took a relatively small signal and relayed it into a much larger signal using these things over here relays do that by using electromagnetic charge that basically attracts a bit of a switch to make the switch magically do its switchy thing have a watch see that so this is the switching mechanism of the relay it causes the actual switch to break and make if you see that it's doing its breaky makey thing so there's three different parts of the switch there's the switch part that is here that is currently connected together you'll see this part and this part are actually touching each other that means the signal going up the center is going to come out of this side and this is what is called the normally closed side of the switch that's because normally when there's no electricity being run through anything well this part of the switch is actually conducting so you can send something into here and it will come out of this side and then there's the other bit here and this is called the normally open contact that's because it's normally open until you send electric charge through the electromagnet and then it will yeah it will close and it will make the contact between these two contacts so you've got two poles to the switch you've got the normally open and they're normally closed and these come in handy in various different arrays this specific relay right here actually has four switches in it there you can see there's one here one here one here and one here and these are all isolated from each other so they can be wired in to different things fire up again oh yeah as time went on the use and applications of relays also evolved and stuff as people found that they had a plethora of uses in fact there was a time starting in the 1930s and stuff where relays actually replaced the functioning parts in mechanical computers so you've got relay computers and this was just before the vacuum based computers came in which were a lot quicker than the clickety clickety traps and there are actually quite a lot of modern diy relay computers about including relay clocks really counters this that and the other so if you're interested in them definitely go and search up really a computer and just hear all the clicky clicky magic oh yeah electromechanical relays come in all shapes and sizes and they are around still everywhere even my modern audio interface has a relay inside it if you listen to this about five seconds after it boots up you'll hear a relay clipping on or off this is to switch some sort of isolated signal in there not 100 sure where it's from but maybe it's because there's a weird noise that happens when it starts and it just kind of bypasses that who knows but regardless you do find them in modern machines and here's a few examples of some relays you've got start a solenoid from a traditional engine starter of a car this is electromagnetic and yeah it's a relay oh just look at that that's so chunky it's a massive solenoid that does a couple of jobs when starting a car including pushing some of the mechanism into the engine to get it going but it also makes electronic contact as you can see the bulb turns on when you flick it this is a reed relay you find them in burglar alarms this that and the other and they are quite silent you don't hardly hear them or you can hardly see them you can also get these in standard integrated circuit packages as well look at that doing this thing so the polarized relay has two choices you can either send it this way you could send it off or you could send it that way so we send it this way but you can also flip the polarity and flip it all the way over to this side and if you turn it off it goes back to the center again so we flick that again it's on you flick it off it goes to this side a post office really has a lot of switches inside the same relay as you can see there's a lot moving in there when it's doing its thing thermal relays use a heating filament to actually warp it into shape so it actually adds a time delay this one has a 20 second time delay so when you flick it on it starts heating up and as it heats up it gets ready to do its switchy thing there we go it's turned on i've also done a video on the museum of everything else youtube channel about an edison thermal switch so check that one out there there's loads of other types of relays as well including latching relays so you can make a one massive massive hard drive if you really want and i'm quite tempted i gotta be honest so the thing that i like about relays is you know for however simple they are in essence you can actually make them do quite complicated things if you gang a load of these things together you can make them do well near enough whatever you want as long as speed isn't uh something you're after if you look at a relay as something that could turn something on and off or one and zero then basically you've got the building block and fundamentals of you know digital electronics so let's start from the top shell we've got a relay here it's receiving five volts this is a five volt relay you can see it's a little bit of a funky one and it's got a switch here it breaks the contact between the five volts the relay coil and going to ground so when i flick this it will do its relay thing and there's a couple of leds connected to the actual switch to show you when the switch is changing its poles this one has a normally open and normally closed light in that really big one but if you look really closely you'll see the connection actually being made so this relay also has two separate switches so we can wire in two isolated signal paths into either side of this thing as well ooh so what happens if we send ground through the switch of the relay and then wire it into the actual relay itself but then also connect the switch as well so we'll make the switch do its initial contact but it's also actually connecting to ground on the actual relay itself so without this we've got a normal and if we put it to itself if i flick this it actually stays on if i unconnect this again it will go back to normal so when you push the switch it completes the circuit so it makes the coil flick down and then this makes the switch actually push forwards but because the ground is also connected there and there it makes it latch on and it stays on because it's making a complete connection when it's uh created so we flick it over it stays there but if i make this connection to the normally closed side of the switch you'll hear that it actually starts buzzing that's because the mechanics in here are sort of making a feedback loop i'm sending this to ground because it's made the connection with the normally closed but the second you put this connection together it actually cuts itself off it turns itself off and anyway i'm getting this sound right there obviously this is very quick and the delay is based on the actual mechanics inside the relay but now if i add a really big capacitor into this circuit you can actually slow this down as you can see here it's actually making a slower click and that's because the capacitor is acting like a bit of a battery in here and it's staying on for longer and you know keeping it at a constant rate the problem with this is you see it's very unsymmetrical and that's when we add two relays to the circuit you get a much more symmetrical clock and if we double the capacitance here we'll actually get it twice as slow so we'll double the capacitance and now we made it twice as slow and it sounds like your car let's go back to the first circuit it may not have been immediately obvious with this latching circuit but basically here is pretty much uh one bit of memory because this is zero imagine this is one it's now one and if we want to bring it back to zero we break this connection here and it's zero again and if we add another relay here to actually break the ground from this so we'll uh put this one over to the switch here to the normally closed and then we'll wire this one into here so the ground actually goes through this relay and into here so now we have a set and we can reset that so now with two relays you've basically got this and you can keep on adding relays like this and adding complexity for instance if you only ever wanted this decision to be made on a clock pulse well all you do is you add another relay that isolates it when the clock isn't being sent in and then you'll make it a synchronous latch three layers have interested me uh no end ever since i ever really got into electronics but i just didn't really it just didn't really make sense i've got to be honest and then recently i was like right i'm going to make something with relays i've always wanted to make something like a relay computer or a relay counter but i'm struggling to find the applications and how much use they are to me for making a relay computer you know i just don't know what i'd use it for i'd probably be building it purely for the sheer joy of it for wait a second why don't we make a special type of relay computer a relay computer that could be used in a musical application and yeah that's it making a relay sequencer uh i want to by the end of this will make quite an elaborate sort of performance sequencer because if you basically take these fundamentals and just keep on building them you can build all manner of parts of sequences you can make an analog to digital converter for instance you can make the sequence you can even make memory for presets with these fundamentals so for this past few days i've been messing around with the fundamentals of making a you know a relay-based step sequencer and this is currently where i'm at and man it looks it looks pretty cool so a quick introduction into step sequence if you don't already know are basically the most basic type of sequencer inside a synthesizer in fact one of the first electronic projects of mine was building a 4017 baby eight step sequencer which is basically and i'm sure if you're into diy synthesis you've built something very similar there's also a project that i made a couple of years ago called the keyboard sequence which is basically an arduino version of the baby eight step sequencer with a few more bits of functionality but the thing is like building anything with relays you've got to go down to the fundamentals of what is actually happening and if you're interested in getting to the fundamentals of this uh i did a video on the museum of everything else youtube channel about step sequences a couple of weeks ago and i basically spoke about things called flip-flops these are the things that basically sit on your breadboard they don't sit on your feet and these flip-flops are also something that i spoke about in the swtpc video a couple of weeks ago and these are pretty much the fundamentals of step sequences they're like a posh version of the set and reset kind of latch thing and for building this sequencer i required a d-type flip-flop that means there's an input that isn't set and reset but the set and reset are in the same input meaning if the voltage going into it is high it sets it and if the voltage going into it is low it resets it and if you're interested in seeing how d-type flip-flops work in sequences we'll go and check out the other video that i mentioned earlier uh basically where i build a sequencer out of flip-flops each of these right here represent a step in the sequence i tried to figure out the d-type flip-flop by myself but i wasn't having much luck it was going all over the place but i found a really good video by simon winders uh basically describing how a d-type flip-flop works with relays and this is basically the simon winders deep type flip-flop the link for that video is also below so if you're interested in the functioning of the d-type flip-flop then i'd thoroughly recommend you looking further into that but basically how these three relays work is these two are acting like these two relays right here and then this one is saving the state of what is being put in us but basically how the d-type flip-flop works is you send a signal in on the d input which is this which chooses whether it's going to set or reset and then you send a clock impulse into there and if you look here i'll be able to write a bit onto this step and if i take my finger off d and press the clock again because there's no signal going into it this will turn off so i send the input high it listens to it when i flick the clock and it turns on if i turn it off it turns off but the thing is if you cascade flip-flops down you can actually send that signal along so for instance i send this high and i put it into the clock you see it's turned on and now on the next clock hit because this d-type flip-flop is actually listening to what the output of this is saying so now this is high so this is like my finger pushing down on this switch it actually listens to that but this one's going zero so this one turns off and this one turns on and i'll push the clock again and it cascades down to this one and it cascades down to this one and i don't need to push my finger down anymore because the bit is actually in it and now it will keep on going around and this is the fundamentals of the relay step sequencer i've also added a reset button over here so now i can reset it this one right here amplifies the clock signal i've currently got a step pro coming into this acting as the clock so if i send the clock in but there was a fundamental issue with writing in the bits doing this the problem is if i am too slow with pushing the button i can accidentally send two in and i didn't want to send two and i only want to send in one and if you don't flick it on the clock pulse you don't actually get it so you need to make another circuit and that's the circuit over here which actually writes in a bit into the sequence but only ever writes one bit so if i flick this so now there is a bit of information in this relay circuit over here waiting to be sent into the sequence so i'm going to push the sequence and now i send that one in and if i push this button any time i can add an extra step but i'll only ever be able to add one step so if i push my finger down it's only added one step in there i've been talking a lot about this on builders vlogs this past week over on my patreon and there's a couple of questions that came up and that was how quick can you make it go well surprisingly quickly actually we'll give it a go right now so it's clicking right now oh it sounds so good let's slowly speed it up i mean i've actually maxed out the uh ah there we go it topped out it topped out at about 410 bpm so you can actually make this code remarkably quickly even though it is just mechanical relays the other question that came up is this is really pushing the actual functionality of relays relays aren't supposed to be constantly turned on and turned off they they can wear out but i've done a fair few tests on this and they've proved to be quite good for instance i left it running like this for i left it running like this for the best part of 10 hours and this is still my test bed and it's still actually amazingly working so yes the relays may break at some point but they're not broken yet this drawing right here is pretty confusing i've got to be honest but the only way to understand it is to just stare at it for quite a while until it starts making sense these red boxes right here represent different relays this square right here is the electromagnetic coil that's the thing that if you send signal in it actually makes these switches do their thing inside each of the relays there are also two switches this side is the normally closed side and this side is the normally open side this may seem a little bit backwards if you know about relays to other relays however i'm using omron relays where actually the normally closed is this side and the normally open is this side sometimes they're around the other way in relays so this first drawing is looking at simon winder's d-type flip-flop i thoroughly recommend you checking out his video because i don't think i'm gonna be able to eloquently put it like he put it so i've bought this back again to show you uh a bit that i sort of forgot about this quite a funky uh implementation in stuff like relay clocks and relay computers and stuff like that so the thing is if you wire up slightly differently and make the most of this mechanical delay and this is shown by this led right here you can see i've made this led basically do a clock pulse and this is what's inside relay debouncing circuits as well but this is working on the fact that it takes a little bit of time from the normally closed and the center of the switch to actually deactivate from each other so you end up getting this tiny little pulse and you can make the most of this tiny little pulse to actually make these flip-flops right here so this relay for instance it receives a clock and it goes into the coil and when the clock hits this actually breaks the contact onto the next clock so this clock only receives ground for a tiny little bit of time before the actual uh clock flicks over and actually disengages this the thing is if you don't do this it'll actually act like an oscillator and go bazz you don't want that you want to be able to save it and this is the memory relay right here and this latches on and off depending whether you want to save a bit in or you don't want to save a bit in this extra relay actually acts as something that amplifies the amount of switch contacts so it doesn't actually do much more than give you more kind of functionality to this basic circuit so depending how many steps you want your relay sequencer to have you build this circuit that many times basically what you do is this q is the carry out and this d is the input this reads it from the last step and the q writes it to the next step this is another part to the step sequencer that is actually similar to the circuit that i made but with digital logic circuits uh over on the museum of everything else youtube channel sequencer video which is touching on the 401 free chip doing this but with chips instead of relays this circuit means that i can write a single bit into the step when it starts so it doesn't ever play more than one and this actually makes the most of other kind of fundamentals of relays for instance you can use the relay's fundamental delay within its function as a actual delay to the circuit so for instance you can make this listen to itself for a lot longer so it's got a delay relay it's got a pulse relay so it sends a pulse it delays that pulse that goes into this setting relay which saves the state and then it sends this out into the sequence so it sends it into a step this step goes high but then when this step goes high it actually resets this whole circuit on top of these two circuits we've got the clock buffer circuit whereas a transistor i know transistor g's and this basically just means that we can plug any clock input into this and it will read it and it will keep us happy forever more and there's also a reset relay and all this does is basically cut the ground from the latching memory relays inside the flip-flops and it basically just wipes the whole sequence clean so taking all of this into account i've built these little modules in front of us these are basically just the parts that are required to build the step sequencer i built it in a modular way so i can potentially build on the idea later on but i sort of wanted to get a proof of concept down of the sequencer actually functioning because you've seen it doing it all it's lightly and ticky things but you haven't seen it actually do its sequencery things and that's when these uh knobs come in handy this box is what i'm gonna build the proof of concept into it's gonna be a eight step sequencer this is primarily built to be sort of an interactive display at the museum so you can actually press play and it will do a sequence loop and stuff and yeah and if this is as awesome as i think it's going to be i'm going to use this as sort of a bedrock to building a way more complicated way more funky sort of pretty much an arturia beatstep pro but out of out of relays purely from the point that relays actually give you that visceral feeling that there's actually something going on and it makes it seem a little bit more tangible and also at the same time it sort of makes it seem a little bit more magic in a way because you're aware of everything that's happening in the circuit because you're literally hearing and seeing all the clicks it's just uh i just find them endlessly fascinating basically so in this eight step sequencer there's basically eight of these modules which are for each step i built all the elements onto separate boards with screw terminals so i can adjust it uh you know if i change my ideas and plans and stuff like here's the clock module there's the reset module and this is a slightly more involved step writing module you can see some of the circuit is on the top and some of the circuit is on the bottom and i built these to those drawings that i showed you earlier so you're going to see all of this come together in a few days in part two of this this project can go either of two ways it can stop here at the eight-step sequencer or i end up getting thoroughly engrossed with this and i end up building a b-step pro the size of a room of relays i sort of hope that the latter is gonna happen because that'll be awesome but i am about to put this together over on a builders livestream this evening on patreon so if you want to see me putting this together and talking and i'll also be filming the video at the same time in the same camera so i'll be doing the live stream and the video at the same time so if you want to support these videos and the museum and stuff because um building really machines aren't actually that cheap these relays are about two pound fifty each so if this big beatstep pro thing is gonna be you'll need like a thousand relays maybe so if you wanna see this live stream and also contribute to the relay fund then go and check it out over there and if you haven't heard it already there's my new single stupid me out which i'll just play you out for a little bit anyway [Music] [Music] you

Channel: LOOK MUM NO COMPUTER

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Keywords: synthesizer, step sequencer, diy, electronics, moog, baby 8, science, physics, music, project, how to, facts, look mum no computer, analog synth, history, retro electronics, technology, old technology

Id: SL9fmA2PdMw

Length: 21min 13sec (1273 seconds)

Published: Sun May 09 2021

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