Charles said:
Just curious about this kind of thing:
http://blog.stayfreemagazine.org/2007/04/are_consumer_pr.html
Have any of you designed things to break?
I know about MTBF, by the way and do understand basic economics. This is
different.
I've never intentionally done that, but many things created from technology
will eventually become obsolete. Sometime, parts are no longer made. A
product I designed, the Ortmaster, uses a parallel port in a special way
and must have MSDOS to run the software. New computers don't come with
MSDOS, and even if you could install it, parallel ports are often no longer
supplied.
In a way, this is fortunate for me, because I am setting up an upgrade
option where I will replace the internal PC Board and supply new Windows
software that can run the system through a serial port or USB. This is a
device that sells for $3000, and the retrofit will sell for about $1000,
for a parts cost of about $100.
This new product contains a PIC, and it would be possible to program
planned obsolescence into the product. It could have a RTC, so after a
certain period of time, it could shut down operation. I was considering
something similar, but not so drastic. The device should be calibrated on a
yearly basis, and the calibration data is contained in the program memory
(which is supposed to be better than EEPROM). The calibration date could be
included, and the software could check this date against its own RTC and
pop up a warning that calibration is due.
Actually I think this is a good idea, because it is very important that
calibration accuracy be assured, and many of these units that I get in for
repair are long overdue. Sometimes when I repair them, the calibration can
still be checked, and usually is pretty close, but sometimes it is off by a
significant amount. I charge a flat rate of $100 for NIST calibration, and
an extra $100 for repair, plus shipping, so it's reasonable. However, most
of the shops that have them don't want to part with them for even a few
days, so they nurse them along until they stop working.
Paul