Introduction: 555 Useless Machine
Almost every project that I made in my life use arduino or just atmegas, but on last electronic lesson in my school I found small integrated circuit called 555. I have heard about it before but I was thinking that microcontrollers are better. I read something about 555 in the internet and I found that this is the most popular integreted circuit in the world! And I have never used it :( I thought that it can be nice to make something completely without any programing and just with basic electronic components. I started to think what can I do with 555, but couldn't find anything intresting. Than I talked with my friend about useless machines and I thought that I can make useless machine with 555, servo, some resistors and switch. And it will be very simple and I don't need microcontroller to make it! I order some 555 on the internet and thought that I can test my design in some simulator. In school we are using electrosym but it's very old and I don't like it. But I read about circuits.io and I thought I will try it, after testing everything I can say that this program is pretty good to start with, it's simple to use and very intuitive. Additionaly it looks soooo good like every autodesk's program :)
What is useless machine? It is machine that haven't anything to do, it is just for making useless things. Like switching off switch :)
Step 1: Parts
- 555 timer I think that you can buy it in any electronics shop, this is head of our useless machine
- Servo, the most popular small micro servo you can find it in RC shops or electronic, it will switch off our switch
- Lever switch, it's important because we will switch it off with servo so it can't be any other type of switch
- resistors, I will tell you values in next steps
- capacitor 100nF
- diode (not LED, rectifier diode)
- batteries (1 cell lipo, or 2 AA batteries)
Step 2: Some Math
On the above photos you see how I calculate resistors values.
I spent 2 hours on calculating values for resistors and all the time I got minus resistance which is impossible I don't know what is wrong. Next day after like hour of searching in google I found that if high state is shorter than low we need to add diode and change formulas a little bit :)
Servo is controlled with 50Hz PWM signal, if we set high signal in this pwm for 1.5ms servo will go to 90 degrees, if you set 2ms it will go to 180 and 1ms to 0 degrees. So when switch is off as high signal I get 1ms and as low signal 19ms together it is 20ms (0.02s) to get the frequency you need to divide 1/0.02 = 50Hz. When switch is turned on I just change high signal to 2ms and low to 18ms. I hope you understand it :) if you want to know more, google 555 and you should find plenty of good tutorials about it.
Step 3: Simulation
While I waited for my parts I started simulating my design in circuits.io. It went very well and everything is working. BTW circuits.io is great program it shows you that servo is moving or if you give to big voltage to LED. In my circuit I added oscilloscope to see the signal while experimenting with resistors. Here is link to mys design if you want to check it out:
Step 4: Scheme
Here is the schema from circuits.io and eagle (I made an eagle schematic to mill a PCB for it, while writing this instructable I found export to eagle option in circuits :)) Below you can find resistors values, they are a litle bit diferent than calculated because there are no as precise resistors, It is possible that you should experiment with resistors values to get it working because resistors are not ideal and have 5% tolerance of value.
C1 = 100nF
R1 = 10 000
R2 = 0
R3 = 247 000
R4 = 16 400
Attachments
Step 5: 3D Files
For my useless machine I had made 3D printed enclosure. If you want you can make it out of wood (it will looks much more better) unfortunately I am not talented in hand making things, so I just designed and printed it.
Step 6: Assembling
Begin with assembly flap with top, is to this you need to use piece of filament (diameter of 1.75) or something similar. Then to top you can screw on micro servo and switch. For screwing servo you should use M2 screws at least 8mm long. To screw arm you should use again M2 screw and screw it on very strongly.
Step 7: PCB
I also made PCB for my machine, I like making PCBs, if you don't just solder it like leg to leg or something I don't know how to say it, just without PCB :D This is my first milled PCB, instead of thermotransfer methodod I decided to mill it with small CNC machine. And at least for this PCB this method is much better because you don't need to deal with ironing it and using acid. But I am aware that milling small traces and pads for SMD componnents can be impossible.
Attachments
Step 8: Enjoy It!
Right now you can use this super machine to make something creative, to change the world, or no, this is just useless thing that turns off itself. But I learned a lot during building it so maybe it is not so useless? And don't forget how many fun it can gives you :D Thanks for reading!

Runner Up in the
Design Now: 3D Design Contest 2016

Participated in the
Circuits Contest 2016
94 Comments
8 months ago
hey,
built per the instructions, but im getting an issue where the servo isnt consistent. sometimes it works, sometimes it doesnt retract, sometimes it doesnt extend fully, sometimes it doesnt retract fully.
any clues on why this would be?
Reply 8 months ago
hooked this up to my O-scope and saw that the wave form was all wrong.
the pulses were ~0.5 and 1 ms, and the period was also wrong. For the retracted stat the on/off time was about equal and the the extended state it was ~18ms (almost right).
not sure how yours worked, but I couldn't get your design to work :/
1 year ago on Step 8
Great metaphor for life...one step forward, one step backwards.
4 years ago
hello,
could you clearly post de values of the 4 resistors? it remains unclear for me looking at the text...
Thank you!
Question 4 years ago on Step 3
Hello Nikus, is that pic of circuits.io? Because when I press the link, it takes me to a place called library.io, then I can sign in with my Autodesk account, but i still cant actually create/view any circuits...
It looks like an advanced version of tinkercad, which i have been using so far...
7 years ago
Needs a much longer delay to switch off - make it a bit more fun.
Reply 7 years ago
Yeah, and the next guy say's "why not to put a delay on that?", "because....... I don't know why to put a delay on a thing not doin'g what?, it still does nothing?".
Quote: can you "DO" doin'g nothing? Isn't that not "do'ing?" ?? .
Gramma: to do is a verb... (I guess), summa: this Ible does something but wan't achive some expections that our "newbe" society expects.
Heil to "Leanardo da Vince", (my mentor, my gee....), HE WAS THE MAN.
HE WAS THE ULTIMATE innovator of the impossible.
The wery srtange thing just accourd me:
Them all these odd guys, (Arist.. Sofo.. Leonard.. Marc.. Tes.. Watt.. Volt... Amp... M'm Curie.. Einstein.. Oppenh.. etc... etc.. ), do NOT come from the USA.
And all of them had a idea of "USELESS" thing
Still, USA claims to be the most educated of what?
Reply 7 years ago
um, sorry old boy, hardly understood any of that.....
Reply 7 years ago
*) my bad, it should read "Leonardo" not "Leanardo", please forgive me Leonardo.
Reply 6 years ago
You appear to be a very young person who cannot handle mild criticism.
You last three messages show this.
Well, good luck to you.
PS: I do speak other languages.
Reply 5 years ago
Thn''x. To my soul I guess I'm about 25 years, but the sad thing, (for me), is that my body is now 66+ years old
Reply 6 years ago
Ooh... the picture of me is when I was 15years old in 1966. My 1'st native language is Finish, (reads Suomi), my 2'nd native language is Swedish, (reads Svenska), I can helpfully understand Norveigian, Danish. I guess I can read and write, speak, and understand the heard spoken English good enough to get by. Let's have a smile here okay?
Reply 6 years ago
Here is your smile!
Reply 7 years ago
There you go. Neither did them in those days living "average" people understand of them "innovators" creating totally useless things.
Reply 7 years ago
Your reply seems rather gramatically challanged. I suggest taking an English course.
Reply 6 years ago
OK. I'll take a course in English, if You promise me to take a course in Finnish or Swedish, and then we can conyinue this discussion
Reply 6 years ago
Gee.. My B,, BRB.. LOL.. to ? ENG.. UK.. or US? again LOL.. them f***. dont? If You don't understand them ible's here wroten, (they come from Global Wide, surprice.. surprice there's a WORLD beoynd the USA), maybe this Instutructable site should be forbidden for NOT US people?
Reply 7 years ago
OK. I'll take another lesson in english, (by watching another film on TV), if you promise me to take another session with your "shrink"
5 years ago
That's a nice device to keep on the desk, in case you get bored.
6 years ago
very very nice!! I also thought of using 555 for mine. you can put in a potentiometer and always adjust the speed of your arm attached to the servo.