555/decade counter 7 seg display help

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zeromod
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555/decade counter 7 seg display help

Post by zeromod » Thu Jun 29, 2006 9:11 pm

Greetings,

Iv'e recently got my feet wet with my newfound love for electronics. The first project I completed was a simple astable 555 timer, moving on to a monostable. I now have on my 15$ breadboard (lol couldnt help but jest at radioshack) a decade counter (4017b) using a 555 ic as the oscillator. I would like to order a grab bag of 7 segment lcd displays and display the count with my leds and also with the lcd display. my question is this, what sort of ic would i need to run an lcd display? or are there 7 seg lcd's that are integrated with an ic that would do this for me, as this would make the wiring and the pinout much easier. i wouldnt mind if this were so as the lcd does not need to run remotely it could just as easily be on top of an ic laying flat on the board. Ive looked at jameco as reffered on these forums and have found a grab bag of 7 segs for cheap but if there are any other ideas id be welcome to listen as im quite an amatuer at this point. I could also post pics of the layout on my electronics blog if anyone thinks that would help, (i can write a true schematic as well i suppose but i hate to lol.) thanks in advance
"There are 10 types of people in this world, those who understand binary..and those who dont."

JPKNHTP
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Post by JPKNHTP » Thu Jun 29, 2006 10:20 pm

-JPKNHTP
-God Bless

zeromod
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Post by zeromod » Fri Jun 30, 2006 1:36 am

Looks like thats leaning in the right direction. A few questions,
it says that the circuit accepts any TTL compatible logic signal so being the amatuer that i am i must ask. My board is using a standard 555cn timer as the osc. for the decade counter 4017be.. As it is now there are 10 leds running from the pinout for the decade counter and as the counter "counts" each coresponding diode lights up. Now Im not familiar with the (74LS90 TTL BCD Counter IC) would this be what the author is using in place of the decade/555 that i already have? And I believe you answered my other question right on the nail but just to confirm, I take it that i need an (74LS47 TTL Seven Segment Display Driver IC) or equivelant as well as a seven segment display in order to display my count. On the TTL matter the author states that "They should not exeed 5V and not fall below ground" this is suitable but once again is their something else i need to know here? Id hate to ruin my board by sending signals that could damage a chip. whew think that covers it but ill throw in a final general question while the topic is open, are you aware of any general datasheet sites? i could use a one stop for pinouts etc. thanks for the link though i think the driver will point me in the right direction at least.
"There are 10 types of people in this world, those who understand binary..and those who dont."

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Sambuchi
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Post by Sambuchi » Fri Jun 30, 2006 2:57 am

zeromod wrote:my question is this, what sort of ic would i need to run an lcd display?
hello zeromod...

7 seg are nice devices.. but LCD's are great!

When you want to start doing PCB projects, you might want to check out the MSP430f449
http://focus.ti.com/docs/prod/folders/p ... 0f449.html

must be the f449... those can drive a softbaugh LCD..

http://www.softbaugh.com/OuterAccessories.cfm
http://www.softbaugh.com/Show.cfm?strPartNo=SBLCDA2

And here are some Board Manufactures this forum came up with..
http://www.servomagazine.com/forum/view ... highlight=


so.. talking $$$$$

you can get the..
MSP430 free from TI
Display 4.75
Boards.. I would say you could make at least 6 boards for $50.00

design a few boards.. look something like this!
http://www.softbaugh.com/Show.cfm?strPartNo=ES449

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Post by ecerfoglio » Fri Jun 30, 2006 6:05 am

it says that the circuit accepts any TTL compatible logic signal so being the amatuer that i am i must ask. My board is using a standard 555cn timer as the osc. for the decade counter 4017be..
Both a 555 and the 4000 series CMOS may be used with a wide range of supply voltages (from 3 V to 15 V (or 18 V? I don´t remember).

If you use a 5 V supply they are TTL compatible.
E. Cerfoglio
Buenos Aires
Argentina

JPKNHTP
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Post by JPKNHTP » Fri Jun 30, 2006 8:59 am

-JPKNHTP
-God Bless

zeromod
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Post by zeromod » Fri Jun 30, 2006 7:04 pm

amazing input from all of you! thank you much. JPK.. thank you for for the references to the pinouts/reference material. I do certainly scavenge from my old pcbs great for dips etc. I beleive I will indeed just lose the decade all together as id hate to go through the work to have out of sync display. I suppose ill get to ordering and start from there. thanks again i think i may have found the single most useful forum on the subject as of yet.
"There are 10 types of people in this world, those who understand binary..and those who dont."

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Chris Smith
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Post by Chris Smith » Fri Jun 30, 2006 7:12 pm

For your compatibility, check your “fan outâ€

zeromod
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Post by zeromod » Fri Jun 30, 2006 7:54 pm

Ok youre right those lcd's do like nice lol. I grabbed those specs as well but i think ill start with the led first as I have a tendency to alter my plans a lot haha. Also my uncle was an engineer with lockheed for a long time and actually makes the pcb for me once im ready for a prototype. I dont do etching myself though but perhaps ill learn down the road. Im also working on another decade counter project with a cool little heart shaped led array which will be mounted to a nice brushed alluminum casing for my daughter, courtesy of jason at ke4nyv.com he is actually taking the time to send me a schematic on the array and I for one cant wait. This is going to end up being an addiction i thinks. thanks again for your help and im sure to stop by when im stumped again.
"There are 10 types of people in this world, those who understand binary..and those who dont."

Robert Reed
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Post by Robert Reed » Fri Jun 30, 2006 8:55 pm

Zero
If you want to light multiple 7 segment digits, then check out this chip 74C926. It is does everything-counting decoding lathcing and driving and multiplexing to boot! Basically for LED, but will work for LCD if you add a 40Hz ac to the backplane.
Any more than two display digits and you will want a multiplexed display-or drive yourself crazy with the wiring.

zeromod
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Post by zeromod » Mon Jul 03, 2006 7:29 pm

Ok now I've hit yet another snag (possibly) I have previously left the full details of my project out due to two reasons,

1. The nature of this project and my "less than certified" standing in the field of electronics would have undoubtedly drawn many "you'll shoot your eye out kid" responses. haha so please refrain in having the knowledge that I have every intention of slowly and proffesionaly performing this project.

2. The obvious knowledge in this field at these forums is a rare treat and a resource that I don't want to lose and due to the fire that other hobbyist and I are drawing right now, the topic is always a touchy one.

All of this aside please refrain from "flaming" me lol. Ok so the timer is infact meant to be mounted into an ABS box to charge a nichrome fuse from two leads which will yes of course ignite a rocket fuse. Now thanks to the input previously given I have selected two diffrent approaches toward my goal. One is a simpler variation of my 555/decade combination. as eventualy the aim will be to fire more than one rocket in a pass. (given that a 555 would have a series of high low passes this would not work for timing techniques) with the decade i can skip counts alowing for an interval inbetween ignites, (hopefully) however as i do of course want a 7 seg as to display my count this will probably be scrapped. ok this one is going to be long so ill try to make it short. Im using nichrome to ignite the fuse, there may be a few rocket/firework hobbyists here so you may be familiar with nichrome, it takes very little to gain an extremely fast rate of heat upwards to the 1400f level. Would anyone know if A, there could be a more surefire way of igniting the fuse, (surefire also meaning safer which is the goal here) or B having perhaps done a project in the same vein have any input that they would like to share, im worried about the intense heat from the nichrome damaging my component, although the leads to the fuse from the board will be quite long are there any safeguards i should have in place for my components? Nichrome and remote ABS mount igniters are common in the hobby unfortunately information on building them properly is not nearly as so. I am also looking into different gauges for the nichrome ive ordered a sampler from pnjresources.com which contains a spool of all sizes offered. I may also have some questions regarding the level of amperage allowed to pass to different gauges at different lenghts, as the leads to the nichrome itself will be long and hence the leads themselves will have resistance. So I may have questions later regarding different resistence with the leads and how to check this and change it on the fly if possible. Sorry again for the humongous post and thanks for all the help.
Note: that softbaugh display was nice but good god that microcontrollers datasheet was hairy lol. thanks again.
"There are 10 types of people in this world, those who understand binary..and those who dont."

dyarker
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Post by dyarker » Mon Jul 03, 2006 9:59 pm

Oh, a rocket launcher.

Why would heat from igniter harm anything? You, and the box, should be at least 50-100 feet away with heavy wire going from box to rocket(s). Use 16AWG or 14AWG speaker wire or power cord.

The counter IC can drive power transistors/FETs to send current to the ignitors at the appropiate time.

Cheers,
Dale Y

zeromod
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Post by zeromod » Fri Jul 07, 2006 8:22 pm

lol good god its so hairy now. Listen I had thought about using cat 5 cable would that be workable? i don't want to fool with terminal blocks on my abs box but id like it to be more robust. so i thought perhaps that i could even use one of those nice little surf mount rj45 jacks? that or phone wire just a matter of how many pair. this btw will be for more than a single launch and Im designing it so that it can be robust enough to expand easily. friggin using bcd latch/decoders and bcd binary/decimal decoders and those dont have a carry out so I have to use dual 4 input nors for the carry and my god my head hurts lol its a bit much to take in example... if this is high and this is high then this is low or if this is low and this is high then this has to be low so this one can be high lmao clock pulses hurt my head now. anyway any ideas on the cat5 in leui of the speaker wire etc. that would be awesome. or I suppose i could go with speaker wire I have different gauges of that handy as well. but cat5 sounded like it could work out to look nicer and be more modular. thanks guys and ill hound you again when i post the schematic maybe ill make ya proud!
"There are 10 types of people in this world, those who understand binary..and those who dont."

dyarker
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Post by dyarker » Sat Jul 08, 2006 6:40 am

The current for rocket ignitors is measured in Amps. See: http://www.publicmissiles.com/images/Ig ... yG-Wiz.pdf

The resistance of a "safe" length of CAT-5 would make ignition unreliable, and RJ connectors definitely won't hack it. Try "Molex" type connectors so you don't have to have terminal blocks on your box.

The logic ICs can drive LEDs okay, but not ignitors. You'll need power transistors/FETs. I only repeat this 'cause you haven't mentioned it yet.

Cheers,
Dale Y

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jwax
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Post by jwax » Sat Jul 08, 2006 3:22 pm

It's unclear as to the distance you're controlling from, to the rockets.
There are "rockets" (Estes) and there are "ROCKETS" (ICBM).
If you're only going 50 feet, your line cord (16 ga) is fine. For further, consider putting the controls near you, with the power supply (battery, IGBT's, FET's) close to the launch site.
dyarker- Nice paper! :grin:

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