ic 555 timer small diagram needed

A CMOS 556 would work, but since you don't need to know how it works, just purchase a timer at the store. Another idea is to scavenge a microwave oven control board, save the keypad. I've done it and it will do what you want.

Getting 15 minutes from a 555 reliably is tough. Instead, set the 555 to run astable at ~2.5 minutes, and use its output as the clock for a 4017.

Diode or all of the 4017 outputs except count 9 to the base of an NPN and a 1K. An example of the "diode or" is best seen in the second partial schematic below. The schematics are representative of what you need to do, not complete. The N/O switch also connects to the commoned cathodes of the diodes. The NPN controls power to the circuit. Pressing the button turns the NPN on, and the 4017 keeps it turned on until the count reaches 9, in ~ 20 minutes. Diode or counts 7 and 8 to another NPN through a 1K - that transistor can control a relay to give you you a ~ 5 minute output.

NPN +12 ---+---+ +------- Vcc to 555 and 4017 and relay | c\\ /e | --- | | | [1K] | | Dx +-o o-+------|

i dont have any decent gadget shops that do what i need..

i need from a push button 15mins off then 5 min on then off waiting for push button again to start again at 115 off etc etc, the microwave controll would allow it to be on for 15 mins and off permenant,, not what i need

Maybe this would help.

Right, so basically I connect to the npn transistor by diodes (or leds?) with pins 1, 2, 3, 4, 7 and 10 and use pins 5and 6 connected to the npn and opto-isolation device instead for switching another npn for a relay. It=92s the same as a diode but using less power than the relay, so I figured that out its now the 555 timer connection and circuit to the cmos chip.

The tech sheet I was looking at started from output 0, this means pins 9 and 11 don=92t use (just incase someone else finds this useful)

right the 555 pinout?

1,is gnd 2, E from npn 3, connect to hi-low on cmos 4,dont use 5,dont use 6, connect to ground? 7, connect c+r to 1 8, V+

please can you confirm I have this correct

Questions. What do the diodes and the switch connect to on the npn, I really need a better drawing. I did see on the tech sheet of the cmos chip it sounds like that the output pins give out different power or something as it suggests that only certain pins to be used to time another decade counter cmos chip, is this right if so do I still use diode to the npn?

Yes those are the correct pins, but you need to add more pins - pin 9 and pin 10. That will give you counts 0,1,2,3,4,5,6,7, and 8. Each count stays active for 2.5 seconds, so the timing cycle is

2.5 * 8 = 20 seconds. Each output (count) goes + for 2.5 seconds. The output is connected through a diode, and the cathodes of t6he diodes are connected together. The base of the NPN is connected to the cathodes through a 1K resistor.

The collector of that NPN is connected to the plus side of whatever power supply you are using. The power supply needs to be between 5 and 15 volts. The emitter of that NPN provides power for the 4017, the 555 and the relay.

No, use pins 6 and 9. They are connected to 2 more diodes. Those two diodes als have their cathodes connected to a 1K resistor, and the other side of that 1K resistor is connected to the base of another NPN transistor. No opto isolator is needed or used.

You will use pin 9, but you won't use pin 11

No - see below.

The base of the NPN, through a 1K resistor.

For a diagram of the 555, see this url:

You will select R1, R2 and C to set the timing for ~ 2.5 seconds. Start with R1 = 33K and use a 50K pot for R2. For C, use a 33 uF electrolytic. You can adjust the pot to "fine tune" the 2.5 second pulses that the 555 will produce.

You can also find a diagram of the 4017 at

Connect the output (pin 3) of the 555 to the clock input of the 4017 through a 1K resistor.

If this is not clear, I can email a jpg schematic to you.

Ed

Groan - you wanted 2.5 minutes, not seconds. Change the word seconds to minutes above. Correction to the 555 components appears below. Also, I added 1 pin too many. You want counts 0,1,2,3,4,5,6 and 7, so you need to add pin 10 (not pins 9 and 10 - do not add pin 9).

^^^ ^^ ^^ Yes, use pins 5 and 6

Aaargh! I figured the timing components for the 555 based on seconds, not minutes. Change R1 to 330K, R2 to a 500K pot, and C to a 220 uf cap to get 2.5 _minute_ timing.

Ed

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seful)

lol i fell asleep sending an email again... didnt see your latest post but the latest mail has an interesting section that the last 2 output pins still need to be connected to the first npn otherwise the 555 and

4017 will power down.. thus i think it also needs to be connected to another diode to the npn to stop power coming back from the other outputs and still allow the latter 2 to send power to both... i really need to get a breadboard and the components..

thanks for the better pictures and diagrams in the links that helped loads! im just awake at 14:30 ahh i got work soon :/ well catch you later like erm 3 am? UK time :D

Right, an update i have created a diagram using m$ paint with BIG thanks to ehsjr's help on this subject! if interested email me and i shall mail you the diagram.

this is for a time delay for the digi-safes, i think it should be good, i was thinking of changing the npn2 for opto-isolator to break / make the connection with the solenoid so you still need to type the pin in etc just only works after the 15 mins are up and in to the 5 min stage..

well so we have it

On Mon, 29 Sep 2008 18:28:35 -0700 (PDT), snipped-for-privacy@yahoo.co.uk wrote:

---

15 minutes is kinda tough to get out of a 555 reliably so, somewhat akin to Ed's scheme, (but with gates instead of diodes(:

news: snipped-for-privacy@4ax.com

Since you Google Groupers can't access USENET binaries I'll email you a .pdf of the schematic.

Also, an LTspice circuit list of the last five stages of the counter follows so you can do a simulation, if you're so inclined:

Version 4 SHEET 1 2580 1364 WIRE 1792 48 -128 48 WIRE 448 96 176 96 WIRE 736 96 464 96 WIRE 1024 96 752 96 WIRE 1312 96 1040 96 WIRE 1600 96 1328 96 WIRE -128 112 -128 48 WIRE -96 112 -128 112 WIRE -240 128 -288 128 WIRE 304 128 128 128 WIRE 592 128 304 128 WIRE 880 128 592 128 WIRE 1168 128 880 128 WIRE 1456 128 1168 128 WIRE -144 144 -176 144 WIRE -96 144 -144 144 WIRE -16 144 -32 144 WIRE -144 176 -144 144 WIRE 304 176 304 128 WIRE 592 176 592 128 WIRE 880 176 880 128 WIRE 1168 176 1168 128 WIRE 1456 176 1456 128 WIRE 1872 208 1760 208 WIRE 2032 208 1936 208 WIRE 176 224 176 96 WIRE 224 224 176 224 WIRE 416 224 384 224 WIRE 464 224 464 96 WIRE 512 224 464 224 WIRE 704 224 672 224 WIRE 752 224 752 96 WIRE 800 224 752 224 WIRE 992 224 960 224 WIRE 1040 224 1040 96 WIRE 1088 224 1040 224 WIRE 1280 224 1248 224 WIRE 1328 224 1328 96 WIRE 1376 224 1328 224 WIRE 1568 224 1536 224 WIRE 2192 224 2096 224 WIRE 2304 224 2192 224 WIRE 1696 240 1648 240 WIRE 1792 256 1792 48 WIRE 1792 256 1760 256 WIRE -288 272 -288 128 WIRE -144 272 -144 256 WIRE -144 272 -288 272 WIRE -112 272 -144 272 WIRE -16 272 -16 144 WIRE -16 272 -48 272 WIRE 0 272 -16 272 WIRE 48 272 0 272 WIRE 224 272 112 272 WIRE 448 272 448 96 WIRE 448 272 400 272 WIRE 512 272 448 272 WIRE 736 272 736 96 WIRE 736 272 688 272 WIRE 800 272 736 272 WIRE 1024 272 1024 96 WIRE 1024 272 976 272 WIRE 1088 272 1024 272 WIRE 1312 272 1312 96 WIRE 1312 272 1264 272 WIRE 1376 272 1312 272 WIRE 1600 272 1600 96 WIRE 1600 272 1552 272 WIRE 2192 272 2192 224 WIRE 2304 272 2304 224 WIRE 1648 288 1648 240 WIRE 1792 288 1792 256 WIRE 1648 320 1792 288 WIRE 1792 320 1648 288 WIRE 1792 352 1792 320 WIRE 1792 352 1744 352 WIRE 304 368 304 320 WIRE 592 368 592 320 WIRE 592 368 304 368 WIRE 880 368 880 320 WIRE 880 368 592 368 WIRE 1168 368 1168 320 WIRE 1168 368 880 368 WIRE 1456 368 1456 320 WIRE 1456 368 1168 368 WIRE 1648 368 1648 320 WIRE 1648 368 1456 368 WIRE 1680 368 1648 368 WIRE 1792 416 1744 416 WIRE 1984 432 1936 432 WIRE 2112 432 2048 432 WIRE 2240 432 2112 432 WIRE 1792 464 1792 416 WIRE 1936 464 1936 432 WIRE 2112 464 2112 432 WIRE 128 592 128 128 WIRE 1792 592 1792 544 WIRE 1792 592 128 592 WIRE 1920 592 1792 592 WIRE 1936 592 1936 544 WIRE 1936 592 1920 592 WIRE 2096 592 1936 592 WIRE 2112 592 2112 544 WIRE 2112 592 2096 592 WIRE 2192 592 2192 352 WIRE 2192 592 2112 592 WIRE 1280 848 1280 224 WIRE 1696 848 1280 848 WIRE 1792 848 1760 848 WIRE 2096 848 2096 592 WIRE 992 880 992 224 WIRE 1696 880 992 880 WIRE 1792 896 1792 848 WIRE 1824 896 1792 896 WIRE 2016 896 1888 896 WIRE 2384 896 2176 896 WIRE 1824 928 1792 928 WIRE 2016 944 1952 944 WIRE 2480 944 2448 944 WIRE 2384 960 2336 960 WIRE 704 976 704 224 WIRE 1696 976 704 976 WIRE 1792 976 1792 928 WIRE 1792 976 1760 976 WIRE 2336 992 2336 960 WIRE 2480 992 2480 944 WIRE 416 1008 416 224 WIRE 1696 1008 416 1008 WIRE 2096 1024 2096 992 WIRE 2240 1024 2240 432 WIRE 2240 1024 2096 1024 WIRE 2336 1024 2480 992 WIRE 2480 1024 2336 992 WIRE 2336 1056 2336 1024 WIRE 2368 1056 2336 1056 WIRE 0 1072 0 272 WIRE 1952 1072 1952 944 WIRE 1952 1072 0 1072 WIRE 2096 1072 2096 1024 WIRE 2480 1072 2480 1024 WIRE 2480 1072 2432 1072 WIRE 1568 1120 1568 224 WIRE 1696 1120 1568 1120 WIRE 2016 1120 1760 1120 WIRE 2304 1120 2304 336 WIRE 2304 1120 2176 1120 WIRE 2368 1120 2304 1120 WIRE 992 1152 992 880 WIRE 1696 1152 992 1152 WIRE 1952 1168 1952 1072 WIRE 2016 1168 1952 1168 WIRE 1920 1264 1920 592 WIRE 2096 1264 2096 1216 WIRE 2096 1264 1920 1264 WIRE 1920 1312 1920 1264 FLAG 1920 1312 0 SYMBOL Digital\\\\dflop 304 176 R0 SYMATTR InstName A1 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\inv 48 208 R0 SYMATTR InstName A6 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\or -208 64 R0 SYMATTR InstName A2 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5v SYMBOL cap -48 256 R90 WINDOW 0 0 32 VBottom 0 WINDOW 3 32 32 VTop 0 SYMATTR InstName C1 SYMATTR Value 1e-8 SYMBOL res -160 160 R0 WINDOW 0 -41 38 Left 0 WINDOW 3 -51 68 Left 0 SYMATTR InstName R1 SYMATTR Value 182K SYMBOL Digital\\\\or -64 64 R0 SYMATTR InstName A3 SYMATTR Value2 trise 10e-9 tfall 10e-9 vhigh 5v SYMBOL Digital\\\\and 1728 800 R0 SYMATTR InstName A9 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\or 2416 864 R0 SYMATTR InstName A13 SYMATTR Value2 trise 1E-6 tfall 1E-6 vhigh 5v SYMBOL Digital\\\\dflop 592 176 R0 SYMATTR InstName A4 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\dflop 880 176 R0 SYMATTR InstName A5 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\dflop 1168 176 R0 SYMATTR InstName A7 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\dflop 1456 176 R0 SYMATTR InstName A8 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\and 1856 848 R0 SYMATTR InstName A10 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\and 1728 928 R0 SYMATTR InstName A11 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\and 1728 1072 R0 SYMATTR InstName A12 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\dflop 2096 848 R0 SYMATTR InstName A15 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL Digital\\\\dflop 2096 1072 R0 SYMATTR InstName A16 SYMATTR Value2 trise 1e-6 tfall 1e-6 vhigh 5V SYMBOL voltage 1936 448 M0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 5 SYMBOL cap 1984 416 M90 WINDOW 0 -28 33 VBottom 0 WINDOW 3 -30 31 VTop 0 SYMATTR InstName C3 SYMATTR Value 1E-8 SYMBOL res 2128 448 M0 WINDOW 0 47 44 Left 0 WINDOW 3 34 80 Left 0 SYMATTR InstName R3 SYMATTR Value 100K SYMBOL Digital\\\\or 2400 1152 M180 SYMATTR InstName A14 SYMATTR Value2 trise 1E-6 tfall 1E-6 vhigh 5v SYMBOL Digital\\\\or 1712 448 R180 SYMATTR InstName A17 SYMATTR Value2 trise 1E-6 tfall 1E-6 vhigh 5v SYMBOL Digital\\\\or 1728 160 M0 SYMATTR InstName A18 SYMATTR Value2 trise 1E-6 tfall 1E-6 vhigh 5v SYMBOL Digital\\\\or 1904 288 R180 WINDOW 0 -30 125 Left 0 SYMATTR InstName A19 SYMATTR Value2 trise 1E-6 tfall 1E-6 vhigh 5v SYMBOL Digital\\\\or 2064 288 R180 WINDOW 0 -38 124 Left 0 SYMATTR InstName A20 SYMATTR Value2 trise 1E-6 tfall 1E-6 vhigh 5v SYMBOL voltage 1792 448 R0 WINDOW 3 24 104 Invisible 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value PULSE(0 5 .02 1E-6 1E-6 1E-5) SYMBOL cap 2288 272 R0 SYMATTR InstName C2 SYMATTR Value 1E-8 SYMBOL res 2208 256 M0 WINDOW 0 47 44 Left 0 WINDOW 3 34 80 Left 0 SYMATTR InstName R2 SYMATTR Value 100K TEXT 2056 1288 Right 0 !.tran .2 uic

Do you need/want a circuit description?

JF

. . .

--- What the heck...

Here's how it works:

When power is first turned on, U5-1 and U5-10 will be held low until C2 charges up through R3. That will force U5-5 low and U5-9 high, resetting the latch comprising U1C and U1D, and U1-13 going low will keep Q1 and K1 turned off.

U5-9 going high will also create a momentary high-going spike by being differentiated by C3 and R4, and will set the latch comprising U3A and U3B. U3-4 being forced high, then, will reset the counter, U2, and disable the astable multivibrator clock oscillator comprising U1A and U1B.

The circuit will remain stable in this state until S1 is made, whereupon the latch (U3A-U3B) will be reset and U3-4 going low will enable the clock oscillator and U2, allowing it to accumulate counts.

After counting for 15 minutes Q10, Q11, Q12, and Q13 will all be high.

That state will be decoded by the AND gates U4A, U4B, and U4C, with the result being that U4-9 will go high at that time.

That high will be presented to the "D" input of U5A and, after the next high-going transition of U2-7 will appear at U5-5, the "Q" output of U5A.

U5A going high will set the latch U1C-U1D, forcing U1-13 high, which will turn on Q1 and energize the relay.

One minute later, Q10, Q11, Q12 and Q13 will all go low and Q14 will go high. Then, four minutes later, Q12 will go high and, when it does, U4-11 will go high. That high will propagate through U5-B with the next rising edge of U2-7 and will reset the latch U1C-U1D.

That will turn off Q1 and K1, set U3A-U3B, reset and disable U2, and stop the clock oscillator U1A-U1B until S1 is again made and the cycle started anew.

The clock oscillator frequency is determined by considering that if 15 minutes can cause a counter's four next-to-highest MSBs to be set:

1 1 1 1 0

then one minute later The MSB will be set:

0 0 0 0 1

and, four minutes later, the "4" bit will also be set:

0 0 1 0 1

and all that'll be needed to turn the relay on will be to decode the "15" (1 1 1 1 0) state and, to turn it off, to decode the "20" (0 0 1 0 1) state as explained previously.

Now, since U2 is a 14 stage binary counter and we need the MSB to go high after 16 minutes, (960 seconds) we can make a table:

STAGE PERIOD

-------|-------- Q14 960

Q13 480

Q12 240

Q11 120

Q10 60 Q9 30

Q8 15

Q7 7.5

Q6 3.75

Q5 1.875

Q4 0.938

Q3 0.469

Q2 0.234

Q1 0.117

CLK 0.059

The period of the clock oscillator will be about 1.8RC, so if we arbitrarily set the capacitance to 0.1µF and the period to 0.059 seconds, we can solve for the resistance:

T 0.059s R = ------- = --------------- = 327,777... ~ 328K ohms 1.8C 1.8 * 1.0E-7F

Since the frequency (about 17 Hz) will probably need to be adjusted, a

750K pot will put it right at about midpoint of the pot's range. JF

thanks john, i did try to email you but it bounced. im sorry this looks like what i put in the ps on my original posting, it absoloutly confuses the heck out of me! i see - or nand and nor gates in the discriptions and have no idea, give me a component like i dunno erm ?? a general npn or even the 555, 4017 ic i understand that. if you could suply a basic components list (Ed's list is basic, some may see it crude- but it works not too many components and many the same... helps when buying as you usually have to buy 10 of something not just 1 resistor say. the way its composed he told me how it works but not why it works - no, and nand etc)

ANYWAY! thanks again, someone reading this will understand and be able to use your information, just im not in deep with electronics. regards Ian

While you might not understand it at first glance, you could learn something from John's post, if you are interested. What John posts is always of value, and that is particularly true in this case. Essentially, the internal circuitry in the 4017 works pretty much the same as the circuit John posted. When you understand what he wrote, you'll also understand what is going on inside a 4017 - and more.

Ed

--
Thanks, Ed, that\'s very kind of you.  :-)

JF

yes i absoloutly agree! that is why i also thanked john (not like some who just put people down) someone who wants and has time to learn indepth about the way it works, me personally i have many hobbies and i also start learning some stuff and then i just give it in as its too confusing or what might seem on the top. i have so many unfinished projects unfinished because things are too costly or i dont have the correct tools or just loose interest... if someone wants to look into my latter project, was kind of interesting all i needed was someone with a vac-forming machine and i could of easly had a final product out of beta range, it was Optical ornamentation "to find hidden cameras" even hidden cameras that dont work.... its called optical augmentation

--
You need to learn how to walk before you hurt yourself trying to fly.

JF