Enough of 'em will make even the sharpest marks dull.
Me? I just design the marks (and pads, if possible) into the project. The places I didn't have physical access, I had access in the FPGA and room for my own logic analyzer.
-- Keith
A test "pint". Now that's *my* kind of design!
I put pads/vias in when possible.
-- Keith
Sounds kinda big. I like to get my grounds within a couple of centimeters or so. ...sometimes closer.
It is if you design it to be there. ;-) Of course that part of the circuit will never need probing.
Well...
-- Keith
Nope. All points have the same number of planes passing through them.
Oh, did you mean airplanes en-route to somewhere else? Chicago would seem to have SF beat there too. I don't want to live in Chicago either. ;-)
-- Keith
The woman who did the board layouts agreed to add it to new designs, but these boards were already in production when I was hired.
-- Link to my "Computers for disabled Veterans" project website deleted after threats were telephoned to my church. Michael A. Terrell Central Florida
You can get dumb otp uPs for under a dollar, and it usually costs more to place cheap parts than the parts cost themselves.
John
That has an IR filter?
--
Thanks,
- Win
Hey, how about a photosensitive pcb-mount tamper detector? If light ever hits the board, the warrantee is void.
We were just discussing assembly cost with my production folks, and decided that, on average, it's costing us something like 20 cents per part, by the time it's all set up, placed, soldered, and inspected. This is for modest production runs - 10 to maybe 40 boards at a whack
- of fairly dense surfmount with a few thru-hole connectors and such.
John
Joerg, Considered Atmel's ATTiny13 series?
Regards, James Arthur
Err, no. IR picked up by CCDs (at least silicon ones) is basically out to about 790nm or so (from memory). To start emitting radiation in this sort of wavelength, something needs to get very hot, maybe 800C. Cigarrettes manage this easily, but nearly all semiconductor packages will be smoking merrily at this point. Long integration times can build up faint images, but the cutoff at 790nm is fairly sharp, and response rapidly plummets to zero.
Actual cost, at one factory, is figured at Y0.1, which is still comparable to the cost of a cheap part.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Yes, the amount I mentioned, 1/10 yen (Y0.1) is 0.09 cent US.
Best regards, Spehro Pefhany
-- "it\'s the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com
Hello Ian,
Yes, it's either longer exposure or tricks to squeeze out some extra dynamic range. I used a Philips NXA sensor in that project. It had some things added to reduce IR sensitivity because that's basically undesirable in imagers but it was still quite sensitive. Then I built three very high speed samplers with diode quads and toroids which resulted in lots of extra dynamic range. You could see stuff in the dark that the eye wouldn't be able to resolve.
There were also IR converters you could hook up in the path but these were very expensive and I don't remember how they worked.
Also, I don't exactly remember if we removed the sensor's glass for the IR tests or not. I believe we had to.
Regards, Joerg
Hello John,
Yes, a four-bitter and maybe even an 8bit uC. But when I asked my distributor about that he said that TI does not promote the use of their MSP430 OTPs anymore. That leaves the range below 90c pretty much vacant, unless you want to go Far East for the uC. Also, there usually isn't an ADC on chip when under $1, something that one really needs when replacing lots of mixed signal stuff.
Placing is really cheap. An 0603 resistor comes to about a cent, part, incoming QC, placement and final QC. Fully burdened. At first I could not believe it myself. Of course, this is in China and a several thousand boards a month.
Regards, Joerg
A former manager (a non-degreed programmer from the 360 days) had a favorite word he had tatooed to his blackboard; "xenocryptophobia". He knew what he was talking about!
-- Keith
Hello Spehro,
Over 1c just for placing? That sounds expensive. Not for a logic chip, of course, but for a resistor.
Regards, Joerg
Is that why there's an extra character in the part number?
--
Thanks,
- Win
indeed. but the total assembled PCB costs 2/3 of the design it replaced
- the 3 $15 chips I replaced with $1 worth of discretes were a big saving too :)
For my next trick, I will design out the 3 legacy components, firstly the 18 $0.56 green LEDs. The customer loves the 17 $0.22 blue LEDs I put in (which sit behind a blue bit of the label, but used to be red), but I like the $0.08 red & yellow LEDs.
I especially like the photodiode that Fairchild made just for us, QSB34CGR. Y'all can buy them now too :)
product testing yesterday, IT LIVES bwahahahahaha
EMC testing tomorrow, should be a doddle (famous last words...)
Cheers Terry
No, they left it off for us :)
I'm pleased to say the toy sat up and barked. Were it not for my deliberate (yeah right) mistake, it would have been first-time. but the CGR part is fantastic, and pretty too :)
oh yeah, cheap too.
Cheers Terry
often used in security systems, to detect opening the enclosure.
I toyed with the idea of hiding a photodiode under a bit of label that doesnt look like it has one, so we could use it to short SCL to 0V to easily allow a USB flash upgrade (the s/w guy hasnt figured out how to do that yet, so we use whip out the PCB and use tweezers)
that sounds about right. our volumes are a lot higher, so assy cost plummets. But I am currently gearing up to do some drop tests, to try and get rid of 8 screws with large washers - the screws cost NZ$0.16 each, $0.30 assembly cost. All up four times as much as the 128-LED driver circuit.
Years back we were designing a range of motor controllers, which had to be low cost. We used an existing micro & s/w, and wrapped all new h/w around it. The original control board had about $45 worth of components, but all the fiddly screws, spacers etc. for the display & buttons (which mounted on the control card) cost $27. custom-made stuff, aaargh. Its amazing how things you dont pay attention to can sneak up and bite you.
Cheers Terry
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