4017 chip won't behave!

You missed that the list is screwed up. That same list shows up on a lot of sellers, but it's their dropshipper who actually sends the items and it doesn't matter to them. If they let you pay for the damn thing, they have to ship it or risk losing their Ebay account.

Interestingly ebay refused to sell to me due to my location, as determined (correctly-enough) by someones IP geolocation database, I tried one free HTTP proxy but the javascript on the page wouldn't run, (probably needs a paid proxy that does https too, or perhaps the return value from the geolocation lookup crashed something at ebay)

--
?? 100% natural 

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

I bought some from a vendor with the same list recently, and I'm in Florida.

On Sun, 16 Dec 2012 15:20:43 -0800 (PST), snipped-for-privacy@virgin.net wrote:

happened across looks just the job:

should be V1. Got to be clear about which one we're discussing here!

--- I've abandoned the 4017 design in favor of the simpler binary counting scheme using the ripple counters, (2 chips VS 6) and V3 was invoked as a test to determine whether the count up to a partial decode could be accurately determined, which it was.

With that figured out, V3 was irrelevant and was eliminated, the intent being to further simplify the circuit by replacing the proposed

555 clock with leftover gates U4 and U5, the output of U4 driving the clock input of U1.

Then, since you say that a half-day window into which the 7 day delay output must fall is OK, the clock's accuracy has to be +/- 6 hours out of 168 hours for the week, which is about +/- 3.57%.

Here's the gated oscillator set up to work at 1Hz:

Version 4 SHEET 1 880 680 WIRE -96 48 -224 48 WIRE 0 48 -96 48 WIRE 144 64 112 64 WIRE 160 64 144 64 WIRE -96 80 -96 48 WIRE 320 80 272 80 WIRE 144 96 144 64 WIRE 160 96 144 96 WIRE 144 128 144 96 WIRE -224 160 -224 48 WIRE 272 160 272 80 WIRE -96 192 -96 144 WIRE 0 192 0 80 WIRE 0 192 -96 192 WIRE -96 240 -96 192 WIRE 144 240 144 208 WIRE -224 352 -224 240 WIRE -96 352 -96 304 WIRE -96 352 -224 352 WIRE 0 352 0 192 WIRE 144 352 144 320 WIRE 144 352 0 352 WIRE 272 352 272 224 WIRE 272 352 144 352 WIRE -224 448 -224 352 FLAG -224 448 0 FLAG 320 80 1Hz SYMBOL cap 288 160 M0 WINDOW 0 -27 5 Left 2 WINDOW 3 -50 62 Left 2 SYMATTR InstName C1 SYMATTR Value 470n SYMBOL res 160 112 M0 WINDOW 0 36 50 Left 2 WINDOW 3 33 78 Left 2 SYMATTR InstName R1 SYMATTR Value 1.24meg SYMBOL 74hc00 48 128 M180 WINDOW 3 -19 12 Left 2 WINDOW 0 21 38 Left 2 SYMATTR InstName U1A SYMBOL 74hc00 208 144 M180 WINDOW 3 -24 13 Left 2 WINDOW 0 17 37 Left 2 SYMATTR InstName U1B SYMBOL schottky -112 144 M180 WINDOW 0 47 31 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D1 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky -112 304 M180 WINDOW 0 48 30 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D2 SYMATTR Value BAT54 SYMATTR Description Diode SYMATTR Type diode SYMBOL res 160 224 M0 WINDOW 0 43 37 Left 2 WINDOW 3 34 63 Left 2 SYMATTR InstName R2 SYMATTR Value 250k SYMBOL voltage -224 144 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value 5 TEXT -208 384 Left 2 !.tran 10s TEXT -208 416 Left 2 !.include 74hc.lib TEXT 216 288 Right 2 ;POT TEXT 168 264 Left 2 ;500k TEXT 168 168 Left 2 ;1% TEXT 296 248 Left 2 ;5% TEXT -120 -64 Left 2 ;C1 PANASONIC ECQV1H474JL TEXT -120 -32 Left 2 ;R1 1.24M +/- 1% METAL FILM TEXT -120 0 Left 2 ;R2 BOURNS 3296Y-1-504LF

with the pot set at mid-range, the output frequency is 1.0Hz, and it has a tuning range of about +20/-13% from zero resistance to full resistance, which is plenty to trim out the tolerance of the cap and the 1% resistor.

After you trim those out, you'll be at the mercy of the thermal and voltage sensitivity of the components, so what kind of a thermal environment will they be living in, and how stable is your supply voltage?

BTW, how do you plan to calibrate the oscillator?

-- JF

happened across looks just the job:

should be V1. Got to be clear about which one we're discussing here!

Thanks, John. I've actually now ordered all the parts for your 4017 based design and have begun laying out the board, so I'll persist with that for the time being and see how it goes. I hope it works as well as it looks! I'll figure out the calibration issue when the time comes. I might even go over to an xtal based clock if stability issues prove a barrier.