Wrong chip

[Kipper4]

Here's the deal
I ordered a batch of 50x lm324s but the vendor sent me 50x
Toshiba ULN2803APG

Data sheet here

http://pdf1.alldatasheet.com/datasheet-pdf/view/182611/TOSHIBA/ULN2803APG/+07373_VRMSHIEE+/1RuzhvELcT+/datasheet.pdf


Apparently 8ch Darlington sink drivers


Question is what use can I make of them if any?


Thanks guys

[PRR]

We used to actually use octal OC drivers by the dozen. Motor control, solenoid thunkers. A flop disk drive could have several. (Especially the odd early Apple drive.)

You could, with great effort, devise some audio use for one maybe two of the little Darlings. But an 8-pack is a lot, and a 400-bag is way too many.

I doubt they are worth much, unless the Raspberry people eat them. (There are "better" interface chips, so maybe not.)

Complain and get refund/credit.

[Kipper4]

Any of you Raspberry guys wanna buy some chips?

Chips for sale.
Chips for sale.
Get your chips here.

[R.G.]

Got 'ny fish to go with?

[samhay]

If you were so inclined/determined, I expect you could make an 8 stage fuzz out of one of these.
Can't imagine you would want or need 50 though.

[Kipper4]

Got 'ny fish to go with?

No but I feel the chinese seller is going to feel battered.
the value of the chip sale price is less than the cost of return postage

Haha Sam
I'm not such a big fuzz fan so an 8 stage fuzz would be a fuzz to far, let alone 50 of the beggers

[garcho]

LED VU meter driver? get your Knight Rider on.

[Kipper4]

What..... Wait a minute.
Is that possible Garcho?
Could be a goer. As a visual add on to pedals for the led lovers

Hmm Wheres Dead Astronaut?

[garcho]

^ did you try the internet? 

if you think there are a lot of TS schematics online, try some LED searches. did you look at the datasheet for the `2803? it can deal with enough current for an LED on each channel. you can use LEDs arranged in a circle, that would look cool, moving along the arc with the amplitude. or color coded, ye olde bar meter, or put knight rider redlights on the front of the pedal that faces the audience. you'll have to finesse the chip to work with your pedal and you'll up the board size and part count, but for LEDs it's ALWAYS worth it 

[Kipper4]

Sorry maybe i should have done more research. Despite posting a link to the data sheet (post 1)
I had no idea what a sink driver,octo oc driver, solenoid thunker was?

I just googled it and came up blank with the term.
uln2803 led driver, led meter,   
except for some ardiuno stuff which is beyond my paygrade. I'm still getting my bonce around analogue stuff.

Perhaps you could point me in the right direction for the round the houses (night rider) amplitude led meter internet search terms.
cheers
Rich

btw  RG I have Kippers to spare too.

[garcho]

^ sorry, i forgot you posted that link because when i clicked on it i got a page that said "AllDataSheet.com is down"

i typed in "led vu meter circuit" on a search engine site. i don't know if this works or how responsive it is but something along these lines:



i know it's not with the 2803, but bare with me. here's the idea: the diodes in series are segmenting the voltage - when your audio signal has enough voltage to pass the first diode voltage drop, the first LED lights up, when there's enough audio signal to pass two diode voltage drops, the second lights up, etc.
use something like a 386 to drive your audio signal, try replacing the 1N4148s with Ge diodes or some other diode with a lower forward voltage and replace each transistor with a channel in your chip.

[garcho]

another search try

a different approach:



again, not with your IC specifically, obviously. and probably different than what will be in your guitar pedal, for a number of reasons. but these might get you on the right path. don't think of the 2803 as an IC, think of it as a group of independent transistors. read up on LEDs and current/voltage. maybe try controlling an LED with a discreet darlington transistor, then try the IC? start with just trying to light up an LED on one channel. then see if you can light up two. then see if you can light it with an audio control signal. then see if the series diode trick steps the voltage, etc.

[Kipper4]

Ok thanks Garcho.
So I might need a booster to up the signal at input, maybe even an amplifier op amp lm308 maybe.
And maybe some Schottky diodes to replace the 4148s
Cheers I'll look into it. Maybe try and breadboard it with a couple of LEDs.

[slacker]

If you were so inclined/determined, I expect you could make an 8 stage fuzz out of one of these.

I reckon you could do some sort of big muff or super fuzz type thing, might give it a go think I've got some of of these kicking about somewhere.

[PRR]

It needs >1.3V at like 20K load, then it turns-on BIG current. LEDs, bah. We clunked large solenoids and fast motors.

I have an antique 120VAC stepper relay here. It could easily be thunked with these parts (the coil can work on 28V DC, and only 58mA). That's one unit. Two if I made a flip-flop but the stepper IS a flip-flop. So that leaves 399 lil' Darlings un-used.

I whomped-up a "linear audio amp" but the input Z was low and the gain was large and variable. By the time I hacked at those problems with more and more parts, I crumpled the paper. The common emitters are sweet for a power switch, but doing audio is like one hand tied behind your back.

If the seller truly goofed, get it fixed; he will be more careful next time. If you maybe ticked the wrong box, eBay your mistake.

[Kipper4]

I goofed not Paul the seller has agreed to send me the right chips. He said something like
"I think there was mistake made"

I thunk I know what you mean. A DC motor snubber. I thunk I remember reading about it way back when I first read electronic 101.

Maybe just file them in the circular file or build some fuzzes.
I don't really have time to do ought with em right now too many breadboard experiments to complete.

I told my three grandsons one day we would build robot masks. With working LEDs. I have some mini electret mic capsules some where along with that crumpled up bit of paper.
Cheers

[PRR]

> motor snubber

Not really.

These chips were "muscles" for "brains". Logic chips and CPUs can do a lot of thinking, but typically have very weak outputs. Like 3V 3mA. The chip-processing needed to do a million micro-thoughts a second without excess heat/cost/size means that a logic gate or CPU typically can't drive a lot more than a transistor or a dim LED.



Here we have some sort of logic/CPU. Following its instructions, it determines it is time to Do Something. Something needing Real Power. Not the ~~0.010W it can do, but Watts.

The CPU lifts pin 1 "high". This turns-on Q1, which applies power to say an incandescent lamp. (These chips go back further than good LEDs.) Pin 2 and Q2 turn-on a fan, which may be 3 Watts of actual power. Instructions say to wait 3 seconds (for the air-flow to get good). Then open the Fuel Nozzle, and spark the Spark Coil. FWOOM! Great balls of fire. Kids, don't try this at home, take it next door.

Early car engine ECU controllers used these same sorts of chips to work the idle-valve, gasoline injectors, fire the sparks, also some idiot lights on the dash (my 2002 still has incandescent idiot lights). Later ECUs do combine some of the smaller power outputs inside the ECU package, but always a few large power-drivers on the board inside the box. Mine works the alternator field coil in mysterious ways, works a solenoid under the back seat to suck-out the gas-tank fumes, energizes a coil around the key-slot so if you lose your key you have to be investigated by the dealer and pay a lot for a replacement. My new furnace has very similar CPU and driver technology (old one was just an eye and a delay).

You can see how chips like this are important to motorized robots.

Thing is: there are newer chips with self-protecting outputs and serial inputs that don't need separate wires for each function. That's easier for many newcomers. (This grumpy old man played with robot-thoughts when Robby was still new and rust-free, and CPUs were room-size, but surplus relays were cheap and could be many-wired to do sequential actions.)

[Kipper4]

I told the grandkids when I was a boy the school computer took up a whole big room and ran 2" tape and printed out on folding paper a mile long that tumbled into a cardboard box.

They laughed.

Just before I  Left school dad worked as a English teacher in an engineering school and got friendly with a the math teacher and his cybernetics wife.
She used to print out pictures of naked women on the schools computer for my brother and I.
The pictures where all made using just type face on the very same folding paper.
She made good use of school time and some young boys happy.

I know sweet F A about logic.

Thanks for sharing I love the stories.

[Quackzed]

now that's funny.

[duck_arse]

ahh, I see [now] - a led level meter for water clear leds. or the other sort. or is it an elapsed-time meter, as the water drains out the sensor holes, the leds turn off?