# New to electronics and need some help

#### Doccarson

Joined Sep 2, 2017
31
So I'll start by saying that I understand if this topic has been broached before and I'm just missing it. For a big of background, I'm an aircraft mechanic, I know the bare minimum when it comes to electronics, well maybe a bit more then that. Though at my work we have specialists who come in for any of the really heavy lifting. So what I'm looking to get into is building a timer triggering device using a 555 chip, from what I can tell its one of the simpler/best ones to use for this purpose. One of the issues is that whenever I start reading up on it none of the explanations for the pins or how to build off of the chip. Any help in this regard would be a major help. Thanks.

#### MrChips

Joined Oct 2, 2009
19,928
Welcome to AAC!
There are many descriptions and tutorials of how the 555-timer circuit works.
Which ones have you looked at so far?

What part of the explanation is giving you trouble?

We cannot supply you with the appropriate answers to suit your needs until we get a better idea of your knowledge level and where you are having difficulties.

Joined Jul 18, 2013
19,738

#### Doccarson

Joined Sep 2, 2017
31
First off I'd like to thank you gentlemen or ladies for your quick and friendly replies. Well most of it perplexes me, I get some of it, like ground is pretty self explanatory and for the rest of it I feel like that monkey from the car garage video. This is what I initially found and its pretty useful if I had a better grasp of how electronics work.

http://www.dummies.com/programming/electronics/components/electronics-components-how-the-555-timer-chip-works/

But its things like the output and if I'm going to be honest, basically the rest of it. I know how I want to operate the circut and what I want it to do, but its connecting all of the middle that makes me confused. Basically I want 0-60 minute selective with a LCD for selection and countdown purposes. And I want it to trigger a flashing LED light/ maybe two that blink back and forth and a audible tone that can be connected to something.

#### philba

Joined Aug 17, 2017
960
Once you add an LCD display into this, you've really moved the solution into the microcontroller and software domain. At that point the 555 becomes kind of extraneous. Not trying to dissuade you from it at all, I find these kind of projects much more interesting and much more flexible. And once you have mastered an LCD, LEDs and buttons/switches, the sky is the limit.

#### ebeowulf17

Joined Aug 12, 2014
3,049
First off I'd like to thank you gentlemen or ladies for your quick and friendly replies. Well most of it perplexes me, I get some of it, like ground is pretty self explanatory and for the rest of it I feel like that monkey from the car garage video. This is what I initially found and its pretty useful if I had a better grasp of how electronics work.

http://www.dummies.com/programming/electronics/components/electronics-components-how-the-555-timer-chip-works/

But its things like the output and if I'm going to be honest, basically the rest of it. I know how I want to operate the circut and what I want it to do, but its connecting all of the middle that makes me confused. Basically I want 0-60 minute selective with a LCD for selection and countdown purposes. And I want it to trigger a flashing LED light/ maybe two that blink back and forth and a audible tone that can be connected to something.
I agree with philba - although almost anything CAN be done with logic ICs (or even discrete components,) many projects just don't make sense to do that way, unless you're doing it just for the challenge. And this would be quite a challenge for a beginner. You could tackle this project after you've done a few (or a few dozen) smaller and simpler ones.

For now, I'd recommend either:
1) Changing the scope of the project (lose the LCD) and learning how to do it with integrated circuits (ICs) like the 555

or
2) Attempting the project you've just described with a microcontroller, which will be much, much simpler in terms of hardware, but will require programming.

#### Doccarson

Joined Sep 2, 2017
31
Well I think I might have misspoke about the LCD. You know the type of display thats really just a number of dots that make up a number. I had found a clock kit at radio shack that had that kind of display and had the buttons to change the time up and down. I'm trying to go for simplicity here, though funny enough if I did have to do some programming I probably could since I've taken a class or two and actually did pretty well. Again I'd like to thank you all for even responding at all, I've been to other forums where people look and say nothing.

#### MrChips

Joined Oct 2, 2009
19,928
Well I think I might have misspoke about the LCD. You know the type of display thats really just a number of dots that make up a number. I had found a clock kit at radio shack that had that kind of display and had the buttons to change the time up and down. I'm trying to go for simplicity here, though funny enough if I did have to do some programming I probably could since I've taken a class or two and actually did pretty well. Again I'd like to thank you all for even responding at all, I've been to other forums where people look and say nothing.
You know the type of display that is just a number of dots to make a number or letter?

This is likely the most common style of LCD.
And the simplest way to get information on to the display is via a microcontroller.

Learn to program a microcontroller and there will be no looking back.

#### BR-549

Joined Sep 22, 2013
4,938
You could use thumb-wheel switches to indicate/set time or tone frequency on a 555 timer. It wouldn't count down....but you don't have program a chip.......just a thought.

#### Doccarson

Joined Sep 2, 2017
31
So when you say it wouldn't count down, do you mean it would just set a specific time of the users selection at that moment the unit would trigger? For instance I set it for 5 mins and 5 mins later it goes off. Its not necessary that they see it count down like a hokey bomb or something, but a device that can only do a set time would have a very limited scope for usage. Unless I misunderstood what you were trying to say.

#### BR-549

Joined Sep 22, 2013
4,938
Sorry...now I am confused. I'm not sure what you want and what you don't want.

#### WBahn

Joined Mar 31, 2012
25,104
First off I'd like to thank you gentlemen or ladies for your quick and friendly replies. Well most of it perplexes me, I get some of it, like ground is pretty self explanatory and for the rest of it I feel like that monkey from the car garage video. This is what I initially found and its pretty useful if I had a better grasp of how electronics work.

http://www.dummies.com/programming/electronics/components/electronics-components-how-the-555-timer-chip-works/

But its things like the output and if I'm going to be honest, basically the rest of it. I know how I want to operate the circut and what I want it to do, but its connecting all of the middle that makes me confused. Basically I want 0-60 minute selective with a LCD for selection and countdown purposes. And I want it to trigger a flashing LED light/ maybe two that blink back and forth and a audible tone that can be connected to something.
What you describe here is significantly more involved than the "timer triggering device" mentioned in your first post would imply.

Is this something you want to do as a hobbyist primarily for learning purposes? Or is this for some project that you need working soon? Very different situations.

If it's a hobbyist-for-learning exercise, then I would recommend building up small pieces to learn the ropes and then start integrating them together. Working with an LCD and a user interface is a major step up and will probably involve using a microcontroller of some kind. An Arduino might be a good starting point for what you are doing.

What do you mean by connecting an audio tone to something?

I would recommend that you take a moment and identify your NEEDS as opposed to your WANTS.

Imagine that you absolutely HAD to have one of these, but every feature is going to cost $10,000. What is the absolute minimum capability that that you can accept? Then what additional features would you want, in order, if someone else was willing to pay to add them one at a time? #### WBahn Joined Mar 31, 2012 25,104 So when you say it wouldn't count down, do you mean it would just set a specific time of the users selection at that moment the unit would trigger? For instance I set it for 5 mins and 5 mins later it goes off. Its not necessary that they see it count down like a hokey bomb or something, but a device that can only do a set time would have a very limited scope for usage. Unless I misunderstood what you were trying to say. If having a timer that the user can set the time delay before it triggers is too limited in scope, you need to do a much more thorough job of describing what the scope is that you looking for. Thread Starter #### Doccarson Joined Sep 2, 2017 31 BR 549 I'm terribly sorry for any confusion, I hope I can clarify in this message. I'd like to build a circuit with the ability to select any specific time from 0 to 60 mins. Once the selected time has counted down to zero it would then trigger a flashing light or lights and a tone. The tone I speak of to help WBahn would send a audible tone into something like a headphone with a 1/4 inch jack. As far as price, well if I've priced most of the components, other then tools, to which I already have these in our Avionics area at work, it should only cost no more then 40 bucks to make this. So to summarize, I'd like to have a device that a headphone with a 1/4 inch headset can plug into. This device counts down to zero from a selective time and once zero is reached a light flashes and you get a tone in the headset, just in case the person doesn't see the light. And as far as the readout, it would be like one of the ones you see on your everyday alarm clock. Funny thing is I pobably already have everything I need when I bought out all of the kits they had at the radio shack going out of business sale. And as far as when I need it, well its not pressing, but I'd like to make it soon, but its not like I need it tomorrow. My issue is I don't know what I need to do to connect all the major components. #### WBahn Joined Mar 31, 2012 25,104 What kind of resolution do you need on the time interval? Why do you need a display like an everyday alarm clock? Why wouldn't a couple of thumbwheel switches be adequate? Is there a reason that just buying a cheap countdown timer, such as one of the many available on Amazon, wouldn't work? There are many that control a standard outlet. It would be a very simple matter of making a flashing light and buzzer (with headphone jack) that could be powered by wall wart plugged into the timer. Thread Starter #### Doccarson Joined Sep 2, 2017 31 Well part of it is that I just want to try doing something different and to get the satisfaction of building it myself, even though I need help with the design. Well I guess the wheel switches would be adequate, but just not as sexy. #### BR-549 Joined Sep 22, 2013 4,938 " I'd like to build a circuit with the ability to select any specific time from 0 to 60 mins. " That would require an understanding of electronics and an appropriate workbench and resources. You really want to integrate. Start off with something like this. http://www.ebay.com/itm/DC-12V-24V-1-99min-LED-Display-Digital-Delay-Timer-Control-Switch-Relay-Module-/152315235344?var=&hash=item2376b20c10:m:maxSZLIZGfDZSu43UxGeONw This will give you a programmable timer with a relay. You can use this relay to start a tone generator that you will build from a 555. That tone generator can feed your headphone. You will still need a properly stocked workbench with necessary instruments. Power supplies...breadboards...components.....and SCOPE. Just a suggestion......if you want to go this way.......your first task is to breadboard the tone generator, while your waiting for your timer. Thread Starter #### Doccarson Joined Sep 2, 2017 31 This is perfect, and lucky for me we have all of the tools at work. We do almost everything on our aircraft oursleves, I say almost since we had a company come in and do the work on our Littlebirds rotorhead, since we don't have the tooling for it. That thing is a pain to work on anyway, one of the driveshafts can't be blemished in anyway, if it get even a scratch is has to be replaced and the part costs 10k. How complected is the tone generator and is it possible to make one that you can tweek the frequency? #### philba Joined Aug 17, 2017 960 You can do what you described for well less than$40 though it would be easy two spend twice that. When you add the LCD, you are into the arduino zone. If I were doing this, Here's what I would get from eBay.
arduino nano $4 + 2.58 shipping 16x2 LCD (hd44780 compatible)$6.49 + 2.69 shipping
tactile switches 10 for $2.38 A bunch of 3mm LEDs 10 for 1.69 A couple of buzzers$2.89 + 2.69 shipping
A solderless breadboard plus jumpers \$5.99
I'd also get some resistors 1/4 watt, various values

These are just some examples, ebay is kind of like Alice's Restaurant if you look hard enough.