shipping costs can be fun high numbers...

@PlasmaHH Depends on what you want shipped

There's things I can get into any corner of the world reasonably safely for 30 euros, there's things that'll cost 600 just to get across the border

@Asmyldof the prices are hilarious at times when you look at ebay listings. a 5kg item shipped for 480USD to europe...

That's a Chinese rate...

or USPS possibly

@Asmyldof The USPS is often very good at delivering things. Other times, not so good. Amazon often ships things to a local thingy, and then has USPS deliver. (United States Postal Service for those that don't know USPS). Odd thing is that most the time it takes the USPS about 4 days to deliver a local package from Amazon. And even worse, the USPS claims on line that package is delivered on the next day.

Over here USPS goes to whatever Freelancer made the lowest offer

Safe to say, I never accept USPS shipment

USPS loses billions of dollars a year. Why does it still exist ? Because in our United States Constitution, it is required that the Congress keep a USPS going.

but the rates are pretty good

I can see PostNL going bankrupt

Anytime a hand off is made from one shipping company to another, the possibility of a fumble increases dramatically

so everyone pays for stuff

But likely the mailing service will be bailed out

Just not the packages

USPS will always be bailed out. Required by Constitution (not just law).

Constitution here has only been changed a few times in 250 years. Very difficult to change our Constituition in the USA

There's no requirement here. Just that sending a letter signed for from Govt to a person to inform them of their outstanding loans and whatever is easier if you have a company that delivers those

But, if DHL says "Look, we know what we're doing, we would like to be vetted for government mailings", that'll solve that issue as well

@Marla Want to buy a bunch of power supplies? >.<

@Asmyldof No thank you. I have observed over the past few days that you seem to be down sizing

@Marla I'm flexisizing

Old stuff going out, newer or other stuff coming in

Supplies come from a batch of stuff I just won in the US

Are any of the power supplies specified for use with a 741 op amp? I am sure that there are lots of folks here on EESE that need a 741 power supply. mmmm

I think all of them will be suitable....

Though you'd need two for just the one

It would be like the audiophiles selling gold connectors. Hurry hurry hurry, get your 741 supplies

I like the way you think

@Asmyldof you won them ? As in a contest ?

At auction

k

Set a whole bunch of auto-bids, turns out some of them ended in my favour

@Asmyldof Ha ! That is how I ended up with so many antique tube radios.

Weirdly the one CMU200 to play with stuck at $200 below my limit, while the other two I put the same number on overshot by more than $100

So depending on how much I like the thing and/or how much hacking I'm able to do software wise, that might become available as well :-D

Anyone got any punchdown tool suggestions?

a sledgehammer?

@PlasmaHH You think a sledge would work for these: digikey.ca/scripts/DkSearch/… ?

thats an awful lot of components, I would not be sure for every of them, but with enogugh skill ...

Damnit. I just got trolled by a bad Digikey link

I'll be in bed till I feel it's safe to rejoin.... I'll be in bed....

@Asmyldof Rickrolled?

@Asmyldof Oh.

o.O dollar just bellyflopped

<- lucky he didn't pay yet

On an IC chip's pins, is high usually "on" and low usually "off"?

@wizzwizz4 Yes

@wizzwizz4 The only exceptions i can think of are with I2C and UART or stuff like reset or erase pins

@Giskard42 Does this (at the bottom of the answer) make sense to you?

Pin 34 vs. 8, 10 etc.

@wizzwizz4 I don't know that communications protocol or anything

but it looks reasonable to me?

@Giskard42 Ok, thanks.

@wizzwizz4 I would suggest that when playing around with an unsure comms protocol, you use a series resistor for everything except power

If you have a 1-10k resistor in series with each connection you make, the chance of blowing anything up becomes very low.

@Giskard42 That is very helpful - it's much better advice than my disclaimer.

Last time I tried to program a micro. I changed a few fuse bits to set the internal clock frequency at 1MHz. So I changed some fuse bits such as CKSEL0:3 and CKDIV8. But later when I tried to program the flash the programmer failed. The error was: Chip enable program error.

I don't know if the uC has damaged

@dirac16 Can you change them back?

@dirac16 Try dropping the programmer frequency down to really low

@wizzwizz4 I have tried to change them back to what it was earlier. But I failed. The programmer doesn't respond at all. @Giskard42 how could I drop it down? And why should it help solve the problem?

@dirac16 It might be possible to resynchronise the programmer to 1MHz.

However, 1MHz might be higher than the baud rate supports.

Increasing the clock speed would affect that actual baud rate, but most flashers have a dropdown instead of a general input box.

@wizzwizz4 I tested the programmer with another uC and it worked fine. But this one doesn't work.

@dirac16 That might be because the baud rate has changed because the clock speed has changed (assuming serial transmission).

Try setting the baud rate to (new frequency / old frequency) * baud rate.

Note: I'm more of a programmer, so this is probably naive.

Imo, the first thing you should do is transmit the signal to set the clock frequency back to normal.

@dirac16 @wizzwizz4 Usually these chips use synchronous programming (SPI or something), so as long as the frequency is lower than a multiple of the clock frequency, it'll sync up

@dirac16 Which chip, which programmer

@wizzwizz4 Only problem is you can't reset fuse bits without programming the chip :<

@Giskard42 I know - that was intended to be read in the context of "once the chip is responding correctly to signals sent".

@wizzwizz4 Ah, okay, sorry :)

@dirac16 if you're using avrdude, try -B 3 or -B 1 : electronics.stackexchange.com/a/49610/25599

@dirac16 Which hardware programmer are you using, though?

@dirac16 Looks like progisp has a config tab that might have a baud rate or speed option

you'd want to drop that to ~1/8x

And here's the hardware

The thing that's marked 5 is the low speed jumper. But it's an old version of what I use. It doesn't have this thing.

@dirac16 You'll need either a standard speed-programmable programmer (like this sparkfun.com/products/9825) or a HV capable programmer to recover your chip.

@dirac16 Unless there's an option in progisp for programming speed.

@Giskard42 In config tab there is nothing for programming speed

@dirac16 try installing AVRDUDE and use the USBASP setting

@Giskard42 ok let me see what I can do..

@Giskard42 sorry I am not able to find any download link for avrdude.

@dirac16 sourceforge.net/projects/winavr/files/WinAVR/20100110/…

@Giskard42 why it doesn't reside on a more formal website?

@Giskard42 I just installed winavr. I know it's a commend-line tool so how should I continue from now on? How to tell it to understand the micro?

Hello, Would You guys have recommendations for a low voltage, high precision lab power supply? I'm looking for a range of 0-10V with a precision of ~1-2mV. Current preferably up to 3 amps.

Fluke PM2811? :-D

Random question time. Say I have a circuit that requires 5v, but the supply can vary between 4v and 5.5v. I was thinking of first dropping the voltage to 3.3v with a linear and then boosting it back up to 5v (the circuit wouldn't ever need more than 100mA). This seems hacky though and a red flag goes off in my head that says "there's already a better solution out there". Any ideas?

@BrandenBoucher a SEPIC or four-switch buck-boost is your friend here

Sepic

hmm. Not familiar with those (I think). Time to google. Thanks!

4 switch is way overkill for so low power

Likely not going to give any improvement in efficiency, of not in fact a reduction

yeah -- SEPIC is probably the better choice at 100mA, but there may be other reasons (such as magnetics availability) to choose the four-switch topology

Well, I think it may first come down to availability and complexity between the two.

yeah, converter-IC wise SEPIC is more common/availiable but requires a bit more magnetics

If there are some small breakouts available, I may just check those out first, regardless which tech it uses.

Can make a small resonant se pic with tiny coupled coil that oscillates at several MHz.

Or dozens of MHz if you make the coil in your PCB

But a chip is easier, I suppose. I'm just one of those mad fuckers that tries to do everything in 4mm2

@dirac16 open a command line, run avrdude -p (chip name) -c usbasp (or usbasp-clone) -B 3

@dirac16 more info here nongnu.org/avrdude/user-manual/avrdude_4.html