Using the 555 Timer

today in the workshop we're working with the versatile 555 timer ic we'll see how the 555 works and how it can be operated in three different modes we'll also build several cool projects based around the 555 timer it's about time we did this so welcome to the workshop [Music] well hello and welcome to the workshop and today we are going to be working with an integrated circuit that is actually over 50 years old yet despite its age it's still one of the most useful integrated circuits ever created now when the microprocessor was first created one of the big advantages of it was this was a chip that we could use for a number of different applications and all we had to do was program it differently and it could serve a number of different functions while the 555 timer actually predates the first microprocessors yet it has the same advantage you can use this tip in a number of different circuits thousands of different circuits you probably have devices that use five five five timers in your home right now and you may not be aware of it and despite the fact that this just celebrated its 50th birthday last year we are still seeing brand new devices come out that are based upon 555 timers and as you're going to see today sometimes it makes a more intelligent choice to use a 555 than it does to use a microprocessor so let's go and learn a little bit more about the 555 timer and the different modes that you can run it in this amazing integrated circuit was introduced by the signetic corporation in 1971. the 555 is a monolithic timing circuit it can be used as a timer an oscillator or as a flip flop it operates from four and a half to 16 volts the 555 can sink or source currents of up to 200 milliamps allowing it to directly drive leds and even relays it can also directly drive ttl logic circuitry allowing it to be used with microcontrollers there are also cmos low power versions of the 555 such as the in555 ts555 and the lmc555 the 555 is packaged in an eight pin package it can either be a dip or a surface mount chip pin one is the ground pin two the trigger pin three is its output pin four is the reset pin pin 5 is control voltage pin 6 is threshold pin 7 is the discharge pin and pin 8 is vcc or the positive power supply internally the 555 consists of a number of transistors resistors and diodes however it is much easier to visualize the internal operation by breaking it down into a few blocks which include a couple of comparators a flip flop an inverter two transistors and a resistive voltage divider the three 5k resistors wired between vcc and ground create a voltage divider now there is a common rumor that the name 555 is derived from the three 5k resistors however this isn't really true one of the employees at cignetix has confirmed that 555 was just a number chosen by someone in the marketing department who thought that it was a pretty cool number with this voltage divider comparator one's negative input will get two thirds of vcc so if vcc is 12 volts for example it will get eight volts at this point comparator 2's positive input will get 1 3 of vcc so with our 12 volt example it will be getting 4 volts the positive input the comparator 1 is connected to the threshold pin on pin 6. the negative input of comparator 2 is connected to the trigger pin on pin 2. now if you're not familiar with the operation of a comparator it's just a component that compares two analog input to voltages and it outputs a digital signal if the positive input to the comparator is larger than the negative input then the output will be high if the negative input is larger than the output will be low let's take a look at comparator number one the positive input to this is the threshold pin on pin six the negative input is two thirds of the vcc so if the threshold is greater or equal than two-thirds of the vcc the output of this comparator will be high if the threshold is less than two-thirds of vcc then the output will be low on comparator two the positive input is one third of vcc the negative input is wired to the trigger pin on pin two if the trigger is greater than one third of vcc then the output will be low if the trigger is less than or equal to 1 3 of vcc then the output of comparator 2 will be high the two comparator outputs are inverted and are sent to an sr flip flop an sr flip flop has two inputs a set and a reset input it also has two outputs labeled as q and not q not q is signified with a letter q with a line on top of it not q is always the inverse of q so if q is high not q is low and if q is low not q would be high the set input will set the output of q high the reset input will set q's output low if both inputs are low then there is no output change having both inputs high is an invalid state and will cause a questionable output on q in the 555 timer only the output not q is used given that logic we can establish a truth table for the 5 5 5 showing the input to the threshold and trigger and what the output from not q would be note that the not q output is fed into an inverter before it is fed out to pin 3 so the output on pin 3 of the 555 is at the same state as the q output of the flip flop now let's take another look at the input the control voltage input on pin 5 is connected to the comparator one's negative this allows modification of the threshold points so it doesn't always have to be at two thirds of vcc you'll also notice two transistors in this design the first transistor is connected to the reset pin on pin four it controls the power to the flip-flop in normal condition you would hold this pin high thus turning the transistor on and turning on the flip-flop if you send the reset low it'll remove vcc from the flip-flop effectively resetting the timer the other transistor has its base connected to the not q output this transistor will therefore be off when not q is low the discharge pin on pin 7 is generally connected to a capacitor as well as a resistor to allow current to flow into the capacitor if not q is low the capacitor will charge because the transistor will be off if not q is high the transistor will turn on and the capacitor will discharge the ground through it the value of this capacitor can be used to set timing on the 555 the 555 can be operated in three different modes a stable mode which produces an output regardless of the trigger input monostable mode which produces an output which is initiated by a trigger and whose pulse width is determined by capacitors and resistors stable mode whose output is controlled by two triggers one that sends it high and another one that sends it low we'll examine these three modes in more detail in a few moments but first let's take a look at a few five five five timers so here we have a number of five five five timers and it's really not that much to look at these are just eight pin dual inline packages and they're very easy to work with on either a sawdust breadboard or on a piece of perf board or even for designing your own printed circuit boards i also have these chips over here and these are five five sixes and what a five five six is is it's just two 555 timers in the same package and so this is a 14-pin package they've got all of the pins of the 5-5-5 plus the power and ground is common to the two internal timers so the vcc and the ground pins there's only one set of those and there's a dual set of everything else so if you're ever building a project that uses two 555s you could always use a 556 and that would work out just fine and it might be a little easier for you to breadboard that or to build a printed circuit board around it but otherwise as i said there's not really much to look at so what i suggest we do is start building a few interesting projects with our 555 timers so now we've seen a bit about the internal functionality of a five five timer and we've learned that it can run in three different modes technically there's actually a fourth mode it can run in something called the schmidt trigger and a schmitt trigger is a component that can take a digital signal and clean it up we've used schmidt triggers before when we talked about digital logic however the schmidt trigger mode is really just an extension of the buy stable mode so we're going to consider that there are only three modes what i want to do now is demonstrate how you wire up the 555 timer for all three different modes and run a quick demonstration of each of the modes so you can see how it works and so let's begin by looking at the a stable mode a stable mode is also called free running or self triggering mode in this mode the 555 works as a rectangular wave oscillator the output is at two quasi-stable states either high or low in astable mode there is no external triggering required to produce an output signal the time that the output signal spins high and low is set by two resistors and a capacitor now here is how we would hook up a stable mode on a 5 5 5 timer the time the output spends high is determined by resistor rt1 and rt2 as well as capacitor ct the time that the output spans low is determined by the values of resistor rt2 and ct by changing the value of these resistors and capacitors we can produce a rectangular output at any frequency within the range of the 555 timer now let's wire a 555 up in a stable mode for this experiment we'll require a 555 timer a 10 microfarad capacitor 3 resistors a 220 ohm resistor a 1k resistor and a 100k resistor a .01 microfarad capacitor this can also be referred to as a 10 nanofarad capacitor a 9 volt battery and an led and here's how we'll wire all of this up in this circuit the 220 ohm resistor is being used as a dropping resistor for the led on the output of the 555 the timing of the output is determined by the 10k and 100k resistor as well as the value of the 10 microfarad capacitor so changing these values will change the output value you might be wondering about the purpose of the .01 microfarad capacitor connected to pin 5 which is the control voltage this is a common arrangement with the 555 and is used to smooth the control voltage that provides an input to comparator number one the whole circuit is powered by a 9-volt battery so now let's wire this up on a breadboard and see how it works and so here's our a stable 555 timer demonstration on a solderless breadboard and you can see my led over here which is the output of it and buried within these wires down here you can see the 555 timer now i'm powering this with a 9 volt battery and so i'm going to connect the batteries positive to get everything going and you can see the results right here the led is flashing roughly once per second and this basically if we were using an arduino would be the equivalent of a blink sketch so it's a good first thing to demo our 555 timer with just as the blink sketch is the first thing we usually use with an arduino now one thing i want to point out that as opposed to an arduino the 555 timer costs less than 50 cents and with all of the other components on the board including the led we've got about a dollars worth of electronics over here so this is certainly a cheaper way of flashing an led plus of course there was no programming involved now the timing of this circuit is dependent as you've seen on the value of a resistor and a capacitor we're basically charging up a capacitor and discharging a capacitor the capacitor in this case is this one over here it's a 10 microfarad capacitor so let's take the power off for a second and i've got another capacitor here i've got a 22 microfarad one so i'm going to pull this one out and we'll put another one in its place make sure i connect that correctly and we'll power that back up now i've got a 22 microfarad and as you may have expected the period has changed it's about twice as long and that makes sense because the capacitor value is about twice as big so it's taking larger to charge up this capacitor than it did the 10 microfarad capacitor and so that's how we can change the frequency or in this case the blink rate of the led so here we have it our first demonstration with the 555 in a stable mode now let's take a look at the 555 timer in monostable mode what can also be called single shot mode in monostable mode the output has one stable state and one quasi-stable state an external trigger is used to change the output from the stable state to the quasi-stable state the output switches back to the stable state after a predetermined period this period is set by an external resistor and capacitor here's how we would wire a 555 timer up in monostable mode we have two resistors rt and ct the trigger is applied to the trigger input on pin 2 and the output is on pin 3. the time that the output spends in the quasi-stable mode is determined by the value of the resistor and the capacitor now let's wire a 555 timer up in monostable mode for this experiment we'll require a 5 5 5 timer a momentary contact normally open push button switch a 10 microfarad capacitor a 220 ohm resistor a 10k resistor and a 100k resistor a .01 microfarad capacitor an led and a 9 volt battery now here's how we would hook everything up once again the 220 ohm resistor is taking the output on pin 3 and acting as a dropping resistor for the led pin 2 which is the trigger input has a 10k resistor that is pulling the input high the input will remain high unless the push button is pressed in which case it will go low triggering the timer the period that the output on pin 3 remains high which is the quasi-stable state is determined by the value of the 100k resistor and the 10 microfarad capacitor which are both connected to pins 7 and 6. once again the .01 microfarad capacitor has been connected to pin 5 the control voltage pin just to stabilize the voltage and the whole circuit is powered by a 9-volt battery so let's wire this up on a breadboard and see how it works now here's our monostable mode demonstration now remember in monostable mode we are triggering the timer and in this demo we're using this push button switch over here but we could very easily be using an incoming pulse that was going low it would do the same thing and the output again is our led and so if i press the push button the led comes on and then it goes off and it comes on for a specific period of time that was determined by our timer we'll try that again we'll do it now once again that timing is determined by a capacitor and once again it's a 10 microfarad capacitor that we have over here and so i'll repeat the experiment we did with the a stable i'll just take the power off of this for a moment and i'll take my 22 microfarad capacitor and put it in place of the 10 and now we'll put the power back on to that and this sometimes activates when you first put the power on and we'll press the switch and as you see the led will stay on longer than it did the time before so once again that timing is being determined by the capacitor and this is actually a very useful circuit you could use this as the input for another device as a debouncing type of circuit you wouldn't need to use as big a capacitor as we have over here but one press of the push button is only going to produce one output pulse even if there's a bit of noise on the push button and so it's a very useful application for the 555 timer the third mode that we can operate our 555 timer in is buy stable mode in this mode the 555 essentially operates as a flip-flop both of the output states are stable the output will stay in one state either high or low until one of the triggers is applied to change the state now here's how we will wire a 5 5 5 timer in bistable mode in this diagram the trigger 1 is applied to the trigger pin on pin 2 and trigger 2 is applied to the reset pin on pin 4. now in this diagram we're showing two resistors which are simply pull up resistors we're also showing push buttons although the trigger could also be a digital input from an external device let's wire up a 555 and buy stable mode for this experiment we will of course require a 555 timer we'll need two momentary contact normally open push button switches three resistors one 220 ohm resistor and two 10k resistors a 0.01 microfarad capacitor an led and a 9 volt battery now here's how we'll hook everything up in buy stable mode once again our 220 ohm resistor is taking the output on pin 3 and acting as a dropping resistor to drive the led pin 2 is our trigger input and it has a 10k resistor pulling it up high pin 4 is the reset input and it's also being pulled up by a 10k resistor when the push button associated with those pins is pressed it will pull that input low thus causing a trigger as we did in our previous experiments we'll be using the .01 microfarad capacitor on the control voltage input in order to smooth the voltage and we'll be driving everything with a 9-volt battery so let's wire that up and take a look at it now here's the third mode demonstration for our 555 timer and this time in buy stable mode and in buy stable mode we require two triggers one to turn it on and the other one to turn it off and our two triggers are these two push buttons a green one here and a red one over here and so if i press the green button our led is on and it will stay on indefinitely it's not going to time out or anything it's not going to turn off the only thing that will turn it off is our second trigger which is the red button here and that will turn the led off we could try that again we can press the green one and what happens if we give it another trigger on the green button we can press this as many times as we want it's not going to affect the state of the led the only thing that will turn our led off as the second trigger with the red button and as you can probably imagine this by itself is a pretty useful circuit you could replace the led with a relay and create a switch where you have a push on button and a push off button and that by itself is quite useful so another great application for the 555 timer so now we've worked with the three different modes of the 555 timer it's actually time to build some projects and i say some projects because in most of my videos we end up by building one or maybe two projects but today we're going to build a number of small projects and i want to do that to illustrate the versatility of the five 555 timer and of course you can take these projects and use them as building blocks in larger projects you could even combine them with microcontroller based products and kind of get the best of both worlds so without further ado let's go and build some things with the 555 timer now for this 555 timer project we're going to build a 10 led light chaser our device will make use of a 555 timer as well as a 4017 decade counter the light chaser will have a variable speed so you can adjust the rate at which the lights chase now here are the parts that we're going to require to build our light chaser we will of course need a 555 timer you'll also need a 4017 decade counter now if you can't find a cd4017 you can also use a 748c401 if you do use the 748c4017 remember not to go over seven bolts in our power supply but as we're using a six volt battery that could just be fine we'll also require a 3.3 microfarad capacitor 10 leds you can use any color you want but i would suggest keeping them all the same color you'll need 10 220 ohm resistors and these will be the dropping resistors for the leds you'll also require a 1k resistor and a 10k trim pot now here's a schematic for a light chaser and while it might appear to be a bit overwhelming most of that is because of all the connections out to the leds and i'll show you in a moment how we can simplify those connections before i do let's just focus on the 555 timer now the 555 timer is simply being run in a stable mode and the frequency of its output is determined by the value of the 3.3 microfarad capacitor and the position of the trim pot so adjusting the trim pot can adjust the speed that the lights are chasing at the output of the 555 on pin 3 is being fed into the clock input on the 4017 and the 4017 is a decade counter meaning that it has 10 outputs and those outputs are being fed to the leds now in order to simplify the wiring i've created this chart for you and the chart shows you the function in the 4017 the actual pin number and the led that is connected to that pin through its dropping resistor so this will make it a lot easier to wire up and it's really not that difficult to wire when you have something like this so let's wire this up and take a look at our light chaser so here's our led chaser wired up onto a solderless breadboard and i want to point something out on this breadboard that may be a bit confusing if you're looking at this because our design had two integrated circuits in it the 555 and the 4017 decade counter and yet it appears that i have three integrated circuits on this board but that's not actually true this of course is the 555 and the 8 pin package and over here buried under this mass of wires is our 4017 decade counter this is not an integrated circuit this is what's called a resistor array and all it is is a series of resistors now this is a 16 pin array and it has eight resistors in it so it's got 220 ohm resistors eight of them and there's one resistor connected from pin one to pin 16 another one from pin two to pin 15 etc etc and so this this prevents me from having to wire up eight independent resistors and so it's a lot easier to wire and it's a lot simpler on board space and of course since i needed 10 of them i've got two discrete 220 ohm resistors over here but if you're building things like this a resistor array is a very handy thing to have now as you can see our lights are already chasing and the chasing effect looks pretty cool now i can go and take the trim plot here and adjust the speed of it so i'll set it down really really slow this is about the minimum over here so this is the minimum speed that we can chase at right now and that's pretty slow and i'll move it up so we can go faster we can continue to go faster to the point where it is too fast where it's just one blur so this is about maybe about the fastest that we'd want to put it at and it's quite a neat effect now of course you could build an equivalent thing out of a microcontroller but there would be a lot of wiring you'd be using a lot of i o ports on the microcontroller and once again this is a much less expensive design than a microcontroller based design and you could also instead of just using leds on the output this could be opto isolators driving something bigger you could even use solid-state switches and use full-size lights for this and if you wanted to extend the casing effect in that way you could put another string of lights after that you could just have two things chasing so this first light would go and also drive an 11th light the second one driving at 12th one etc there's a lot of possibilities over here as to what you could do with this very basic chaser design our next project is a latching switch a push on push off switch we'll be using one push button as our input and we'll drive an led on the output for this demonstration our project uses a 9-volt battery as its power supply now here are the parts you're going to require to build this will require a 5-5-5 timer a 1 microfarad capacitor 4 resistors a 220 ohm resistor two 10k resistors and a 100k resistor a momentary contact normally open push button switch an led for the output and a 9 volt battery to power everything now here's how we're going to hook everything up once again our 220 ohm resistor is just a dropping resistor for our led the two 10k resistors form a voltage divider and the center of this voltage divider is connected to both pin 6 pin 2 and to one side of our push button switch the other side of the push button is connected to one side of the one microfarad capacitor and to a 100k resistor which feeds the output of pin 3 back into the capacitor to charge it and the whole thing is powered by a 9 volt battery so let's hook all of this up and go and take a look at our latching switch in action now here's our latching switch wired up as usual on a solderless breadboard with the 555 buried in here and a few components and here is the push button itself and the led we're using for a demonstration and when i push the push button amazingly the led lights up and it's going to stay lit until i press the push button again in which it turns off which is of course the desired action now it's a very simple demonstration but keep in mind this doesn't have to be an led on the output it can be a relay or it could be an optical isolator you could be driving something else with it so this is a very useful circuit and again i'll remind you about the cost of the components for less than a dollars worth of components we built something that we could have built with a microcontroller but was actually far easier to build with a 555 timer in this 555 project we're going to build a small dc motor controller this is a unidirectional controller that has a speed control we'll be building it using a separate motor power supply and you can use a variety of motors and power supplies with this design now here are the components we're going to need to build the dc motor controller we'll require a 555 timer and a 100k linear potentiometer we'll also be using an irf-520 mosfet on the output now you could use a different mosfet if you wish will require a 1k resistor three 1n4004 or equivalent diodes and two 0.1 microfarad capacitors our circuit will be powered by a 9 volt battery we'll be driving a small dc motor and we'll also need a power source for our dc motor now here's how we'll hook up our circuit we're using the 555 timer in an a stable mode the frequency of the output is determined by the 0.1 microfarad capacitor tied between pin 2 and ground and the resistor tied between pin 7 and the vcc the pulse width is dependent upon the position of the potentiometer with the two diodes modifying the pulse the output on pin 3 is fed to the gate of our mosfet the mosfet then drives our motor and note that we have a diode across the motor that protects from any back emf that may be generated by the motor so let's hook this up and see how it can control our dc motor so here's my motor controller wired up onto a solderless breadboard as usual and you can see over here i've got my potentiometer which is my speed control here is the mosfet the power mosfet that is going to drive the motor and over here is my fan and my fan is mounted on a little piece of perf board this is something you may have seen before i've used it in previous videos and it's just one of the things i use for prototyping so i find this very easy to use whenever i'm trying to test out a motor now this motor runs on six volts so as you can see over here i've got four double a batteries powering it and i've got a nine volt battery powering the motor driver itself and so i'm going to just turn the speed control there we are at full speed and we can reduce to speed bring it lower if we wish bring it quite low if we want to and so we get a nice control over the speed and of course we've seen arduino designs that use pulse width modulation to do the same thing but once again i want you to bear in mind the cost of the devices over here we're using essentially the same mosfet that we would use with an arduino-based design but we're using a very inexpensive 555 timer chip and so this is a much cheaper design than an arduino-based design and if all you want to do is control the speed of a dc motor this will work great now you could choose a different mosfet if you wanted to this one has a reasonable rating on it but you could get a one that's rated at a higher current to drive a much bigger motor this mosfet also is rated for a much higher voltage so you certainly don't need to restrict yourself to just a six volt motor you could do a 12 volt or even a 24 volt one with this and so it's quite a versatile design so if you're looking for a pwm motor control and you don't need direction control you might want to consider using a 555 timer instead of a microcontroller in this 555 timer project we're going to build a simple touch switch our touch switch will use two wires or plates and when you touch them the switch will be activated in our case we're going to drive an led but of course you could add a relay or opto isolator and drive something other than an led if you wished to build the touch switch you'll require a 555 timer an led two resistors one of them 220 ohms and the other 100 kilo ohms two capacitors a 0.01 microfarad capacitor and a 0.1 microfarad capacitor and we'll be powering this with a 6 volt battery now here's the wiring diagram for our touch switch in this case we're using the 555 in a monostable mode and as you recall in monostable mode when the 555 is triggered it will produce an output pulse of a predetermined width that width is determined by the value of a resistor and a capacitor in this case the 100k resistor connected to the discharge pin on pin 7 and the .01 microfarad capacitor that is connected to the threshold pin on pin 6 determine the output pulse width now i've got it designed so that when you touch the switch where you touch the two plates the led will only come on for about a second but you can change that period of time by adjusting that resistor in that capacitor the other resistor the 220 ohm resistor is of course just a dropping resistor for our led so let's wire up our touch switch and take a look at it in action so here's my touch switch wired up on a solderless breadboard and for touch switch sensors all i used was a couple of pieces of wire you can see them back over here if you look carefully there on the breadboard and when i touch these together the led should light up so let's just do that and the led does indeed light up when i touch this and so another very simple 555 demonstration now remember because this is a timer the value of a capacitor and resistor are determining how long the led would be on so you could change those values and actually keep the led on for a long time even a couple of minutes if you wanted to and that might be a useful type of us arrangement to have something that you touch to just put a light on for a predetermined period of time there's a lot of possibilities here and of course you don't need to use just an led on the output as with all of our demonstrations over here and so another good use for a 555 timer this 555 timer project can be used to test the operation of servo motors it works with six volt servo motors which are the common hobby type that we normally use in our projects it has two buttons one to send the servo in forward and another to send it in reverse to build this project will require a 555 timer two momentary contact normally open push button switches we'll need five resistors a 220 ohm resistor two 10k resistors a 33k resistor and the 68k resistor will also require a 0.1 microfarad capacitor i'm using a 2n 2222 transistor in this design but you can use any equivalent npn transistor and we'll also be powering everything with a 6 volt battery now here's how we're hooking up the circuit the 555 in this mode is acting as an astable multivibrator whose frequency is determined by the capacitor tied to pin 2 and the resistor tied to pin 7. the pulse width is determined by the two different resistors tied to the push button switch and this is why one of them will send the servo forward and the other will send it backwards the output of the 555 is connected to the base of our transistor through a resistor because transistors are current driven so let's hook this up and see if it'll move our servo motor and so here's my servo motor tester circuit and as always i've got it on a solderless breadboard i've got my two push buttons which should control the direction the servo is going and naturally i have a servo motor connected as well and this is being powered by a six volt power source which is uh four uh double a batteries in this particular case and so pressing this button should move it in one direction and pressing this one moves it in the other direction and it seems to work very well one thing i notice actually compared to some arduino circuits is there's no chattering on the servo when it's sitting there stationary it's just sitting there perfectly stationary doing nothing which is actually great and that's because of course it's not actually getting a signal right now and so it does have an advantage over that kind of a system and you could use something like this to actually drive a servo motor not just test a servo motor but of course you would need to experiment a bit with the value of resistors that were attached to the switch or whatever it was that you were using in order to drive the motor but again another great use for a 555 timer so this brings us to the end of our look at the 555 timer but it's by no means the end of the number of applications that this amazing little device has in fact quite possibly we'll be using these devices 50 years from now now if you want to get a bit more information about the 555 or if you'd like the hookup diagrams for all the little projects we built just head over to the dronebotworkshop.com website where you will find an article that accompanies this video and there's a link below the video to that article and while you're on the website if you haven't yet please sign up for my newsletter it's not a spam letter by any means of course and it's not a sales letter it's just my way of letting you know what goes on here in the workshop and all i need from you is your email address and if you want to discuss the 555 or if you want to perhaps show off some of the projects that you may have built with this amazing little timer a great place to do that is on the dronebot workshop forum where you'll find a number of other electronic enthusiasts who not only work with five five five timers but with microcontrollers and all sorts of great things and the forum is free to join there's a link below the video to joining the forum and of course if you haven't subscribed to the youtube channel please do i love getting new subscribers and i'd be honored if you would subscribe all you need to do is hit the subscribe button and also click on that little bell notification and assuming that you've enabled notifications on your youtube then you'll get notified every time that i make a new video so until we meet the next time please take good care of yourself of course please stay safe and i will see you again very soon here in the dronebot workshop goodbye for now [Music] you

Channel: DroneBot Workshop

Views: 981,746

Keywords: 555 Timer, 555 timer projects, 555 timer explained, motor control circuit, light chaser, touch switch, toggle switch, servo motor tester, ne555, 555

Id: ABWU7FlM1T0

Length: 42min 17sec (2537 seconds)

Published: Sun Mar 13 2022