RPM Meter
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From: Grant on 30 Jul 2010 19:08 On Fri, 30 Jul 2010 20:58:36 +0100, "markp" <map.nospam(a)f2s.com> wrote: > >"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message > >> [1] I *still* need a good, small, low-drop current limiter for use as >> a self-resetting fuse. The ideal part would be a SOT-23 whose current >> limit is set by one resistor, thermal limits, and retries at full >> current once in a while. How come nobody makes one, at least past 5 >> volts? Polyfuses sort of suck. > >Here's an EDN article about low dropout constant current source (figure 2 in >the article): >http://electronicdesign.com/article/components/low-dropout-current-regulator-improves-led-driver-.aspx > >I'm wondering whether you could add another resistor between R2 and ground, >and in-between them put an N channel MOSFET. You could detect current >limiting condition with an ADC input from the voltage at the top of that >second resistor and turn off the FET, thereby isolating the supply from the >output. You could program it to retry once in a while once it had detected >current limiting. Not exactly a 1 chip solution though.... Nor would it protect during startup or watchdog reset while the processor is not active. Protection needs to be simple, reliable. Add too much complexity and the gremlins will find a weakness and hit. Grant. > >Mark. >
From: David Eather on 30 Jul 2010 20:33 On 31/07/2010 8:50 AM, Jim Thompson wrote: > On Sat, 31 Jul 2010 08:10:15 +1000, David Eather<eather(a)tpg.com.au> > wrote: > > [snip] >> >> Thanks for the help, but no joy. I'm giving up on it. > > How about the RPM meter? IIRC you wanted pulses to count. Trivial to > do. Contact me if you need help. I'm giving up on having a look at ftp://jjlarkin.lmi.net/DoubleTach.jpg. Whatever is going on it seems to be beyond my power to fix (I changed to windows XP firewall, tried multiple FTP download clients - including with passive mode - I suspect it is my network setting which are crewed down for security and which I won't change) > > Likewise if you want a DC voltage versus RPM. > > Let me know. > > ...Jim Thompson My only bit in the thread was to suggest an analogue solution to the OP's request for a way to check his malfunctioning digital device. Many thanks for the offer of help.
From: Grant on 30 Jul 2010 21:23 On Sat, 31 Jul 2010 10:33:13 +1000, David Eather <eather(a)tpg.com.au> wrote: >On 31/07/2010 8:50 AM, Jim Thompson wrote: >> On Sat, 31 Jul 2010 08:10:15 +1000, David Eather<eather(a)tpg.com.au> >> wrote: >> >> [snip] >>> >>> Thanks for the help, but no joy. I'm giving up on it. >> >> How about the RPM meter? IIRC you wanted pulses to count. Trivial to >> do. Contact me if you need help. > >I'm giving up on having a look at ftp://jjlarkin.lmi.net/DoubleTach.jpg. Here: http://grrr.id.au/image/DoubleTach.jpg If John L. objects to my republishing, I'll happily remove it, so be quick ;) Grant. >Whatever is going on it seems to be beyond my power to fix (I changed to >windows XP firewall, tried multiple FTP download clients - including >with passive mode - I suspect it is my network setting which are crewed >down for security and which I won't change) Fair enough, usually ftp sites are easy to get to, but fewer people access ftp these days. Grant.
From: markp on 30 Jul 2010 23:40 "David Eather" <eather(a)tpg.com.au> wrote in message news:Ja6dndy9EtbN8s7RnZ2dnUVZ_gydnZ2d(a)giganews.com... > On 31/07/2010 8:50 AM, Jim Thompson wrote: >> On Sat, 31 Jul 2010 08:10:15 +1000, David Eather<eather(a)tpg.com.au> >> wrote: >> >> [snip] >>> >>> Thanks for the help, but no joy. I'm giving up on it. >> >> How about the RPM meter? IIRC you wanted pulses to count. Trivial to >> do. Contact me if you need help. > > I'm giving up on having a look at ftp://jjlarkin.lmi.net/DoubleTach.jpg. > Whatever is going on it seems to be beyond my power to fix (I changed to > windows XP firewall, tried multiple FTP download clients - including with > passive mode - I suspect it is my network setting which are crewed down > for security and which I won't change) > > > >> >> Likewise if you want a DC voltage versus RPM. >> >> Let me know. >> >> ...Jim Thompson > > My only bit in the thread was to suggest an analogue solution to the OP's > request for a way to check his malfunctioning digital device. > > Many thanks for the offer of help. > > Try this, it's a short url to that link: http://tiny.cc/7m8a3 If the above works, go to http://tiny.cc/ and put in the url you are looking for to convert. This would only work if HTTP redirect works when putting in the full address doesn't, so IMO this solution is unlikely to work, but worth a go. Mark.
From: markp on 30 Jul 2010 23:58
"David Eather" <eather(a)tpg.com.au> wrote in message news:Ja6dndy9EtbN8s7RnZ2dnUVZ_gydnZ2d(a)giganews.com... > On 31/07/2010 8:50 AM, Jim Thompson wrote: >> On Sat, 31 Jul 2010 08:10:15 +1000, David Eather<eather(a)tpg.com.au> >> wrote: >> >> [snip] >>> >>> Thanks for the help, but no joy. I'm giving up on it. >> >> How about the RPM meter? IIRC you wanted pulses to count. Trivial to >> do. Contact me if you need help. > > I'm giving up on having a look at ftp://jjlarkin.lmi.net/DoubleTach.jpg. > Whatever is going on it seems to be beyond my power to fix (I changed to > windows XP firewall, tried multiple FTP download clients - including with > passive mode - I suspect it is my network setting which are crewed down > for security and which I won't change) > > Another thing that it might be is a DNS problem. That might be a common problem to all your ftp clients (you could try to ping jjlarkin.lmi.net from a command box or try the link below). ftp://66.117.156.8/DoubleTach.jpg |