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by emma1997
Tue Nov 16, 2021 10:48 pm
Forum: General discussion
Topic: Second opinion on this circuit please
Replies: 29
Views: 752

Re: Second opinion on this circuit please

Actually the Pi has no problem safely shutting itself down with software only. GPIO3 is for powering back up (as long as you don't mind waiting a minute or two for OS to boot every time. The whole controlling power via microswitches thing makes no sense to me. Is there such a thing as drawing too li...
by emma1997
Tue Nov 16, 2021 10:24 pm
Forum: Off topic discussion
Topic: Controlling Power (12 VDC)
Replies: 14
Views: 573

Re: Controlling Power (12 VDC)

hack the line before the flasher unit Of course... that is obviously the simplest approach. This would not be the first time looking at a post thinking "Pure genius! Why didn't EYE think of that?". I definitely agree hacking wires is better than hardware kluge or even software fixes. But ...
by emma1997
Tue Nov 16, 2021 9:01 pm
Forum: Beginners
Topic: Budget rc car with high speed
Replies: 12
Views: 396

Re: Budget rc car with high speed

I think "budget" and "Pi RC car" do not fit in the same sentence. Lowest cost First Person Video by far would be using a generic video tx. $5 camera, $5 tx, $10 car. Maybe double that if you are not a good shopper. Or 10x that if you really want to use a Pi with WIFI and biiiiigg...
by emma1997
Tue Nov 16, 2021 8:41 pm
Forum: Off topic discussion
Topic: Controlling Power (12 VDC)
Replies: 14
Views: 573

Re: Controlling Power (12 VDC)

IME not very many here compared to most other forums. IDK why, maybe because the regulars here set such high standards for correctness and general helpfulness. Or maybe I just don't notice because I'm one of the boneheads. lol However there do seem to be a few sides missing in that cube. I am trying...
by emma1997
Tue Nov 16, 2021 8:24 pm
Forum: Beginners
Topic: is there a multiple pi power system??
Replies: 7
Views: 270

Re: is there a multiple pi power system??

Unless i"m missing something simplest would be connect one GPIO to GPIO3 on each Pi to be rebooted or shutdown. The master controls which and for how long. No slave programs to be written or other hoops to jump through since OS responds to GPIO3 pin automatically. Similarly GPIO from the master...
by emma1997
Wed Nov 10, 2021 5:44 pm
Forum: Off topic discussion
Topic: Power supply from 42V DC to 5V DC
Replies: 15
Views: 833

Re: Power supply from 42V DC to 5V DC

I think you might be confusing those with switchers etc that do use PWM. In reality ideal diode is no better than linear semi or resistor in respect to efficiency. They will all waste exactly the same amount of power as heat. Their forte is extremely low forward drop but that only means you would ne...
by emma1997
Wed Nov 10, 2021 5:09 pm
Forum: Off topic discussion
Topic: Power supply from 42V DC to 5V DC
Replies: 15
Views: 833

Re: Power supply from 42V DC to 5V DC

I can power it from 48v of an e-bike Probably not a good idea because 48v systems (theoretically 55v fully charged) can go way over Vmax for lm2596hv and others like the Polulu too. Depending on source seen some '48v' lion chargers push 60v and beyond. Contrary to popular opinion not that damaging ...
by emma1997
Fri Nov 05, 2021 7:41 pm
Forum: Off topic discussion
Topic: Power supply from 42V DC to 5V DC
Replies: 15
Views: 833

Re: Power supply from 42V DC to 5V DC

Maybe worth mentioning that I was able to use vanilla lm2596 in a pinch by adding a dozen or so penny diodes in series. They do warm up a bit and waste a little power but no fireworks. I personally have no experience with the Pololu product and probably won't considering one can buy dozen or two lm2...
by emma1997
Fri Nov 05, 2021 7:22 pm
Forum: General discussion
Topic: Can I control my raspberry pi with a key fob ( so as to control my servos )
Replies: 13
Views: 459

Re: Can I control my raspberry pi with a key fob ( so as to control my servos )

I've used exactly that same item (4 dongle kit) as part of my security system and found it reliable well beyond the advertised 200m range. It uses 12v battery unlike coin cells or other 3v like most rf fobs. To think wifi can LEGALLY compete is wishful thinking. Specially Pi which IME has worst rang...
by emma1997
Fri Nov 05, 2021 6:32 pm
Forum: Off topic discussion
Topic: Power supply from 42V DC to 5V DC
Replies: 15
Views: 833

Re: Power supply from 42V DC to 5V DC

I agree the advice to use any linear regulator circuit, transistor or 7805, is grossly incompetent advice. Opto isolator is often suggested on this forum usually serving little purpose but in this case beyond ridiculous. That member has more problems than language which can cause major heartache her...
by emma1997
Fri Oct 22, 2021 10:30 pm
Forum: Troubleshooting
Topic: Home alarm system with mc-38 reed switch
Replies: 15
Views: 554

Re: Home alarm system with mc-38 reed switch

twiggyxlr4 wrote:
Tue Oct 19, 2021 8:31 am
My question is : Will I need anything extra besides the wire and sensors( excepting the coding side obviously )
I thought my answer (no) was pretty clear. However you are free to pursue solutions involving more cost and effort as advised by others.
by emma1997
Fri Oct 22, 2021 10:14 pm
Forum: General discussion
Topic: GPSD users: Time travel bug hitting this weekend
Replies: 32
Views: 1237

Re: GPSD users: Time travel bug hitting this weekend

LT, I'm surprised to hear that suggestion coming from such an experienced expert like yourself. I think even first year engineering student knows oscillation overthruster is the proper device. I'm sure anyone from Banzai Institute will back me up on this. Right tool for the right job is what I alway...
by emma1997
Fri Oct 22, 2021 9:30 pm
Forum: C/C++
Topic: Why should i use c++ not c?
Replies: 111
Views: 4882

Re: Why should i use c++ not c?

Except of course the compilers themselves which have changed dramatically. It may take some compile options to suppress some warnings. Yes, I've noticed that "gcc -w" works wonders in this regard. I had to laugh at a CS student who told me her program was now GUARANTEED to run perfectly af...
by emma1997
Fri Oct 22, 2021 8:02 pm
Forum: C/C++
Topic: Why should i use c++ not c?
Replies: 111
Views: 4882

Re: Why should i use c++ not c?

IME just the opposite has proven true. Seems like older programs no longer compile w/o errors or at least warnings with latest bright and shiny GCC/Clang versions. On the other hand quarter century old Turbo C still runs fine under W11 on latest top end PC (Pi4/Buster too). SDCC another of my favori...
by emma1997
Fri Oct 22, 2021 7:46 pm
Forum: General discussion
Topic: GPSD users: Time travel bug hitting this weekend
Replies: 32
Views: 1237

Re: GPSD users: Time travel bug hitting this weekend

You are forgiven...

...

...

...

THIS time !!!
by emma1997
Fri Oct 22, 2021 7:43 pm
Forum: C/C++
Topic: Why should i use c++ not c?
Replies: 111
Views: 4882

Re: Why should i use c++ not c?

Why should i use c++ not c? IME hardly ever. Specially hobby or embedded (there's that word again!). More a drawback than benefit unless you're tangled up in hugely complex or multi-team project. Can you spell BLOAT? I'm also a big fan of K&R (aka C minus minus) as opposed to all this fancy-shma...
by emma1997
Fri Oct 22, 2021 7:33 pm
Forum: General discussion
Topic: GPSD users: Time travel bug hitting this weekend
Replies: 32
Views: 1237

Re: GPSD users: Time travel bug hitting this weekend

Relatively few I'd wager.

GPS is by far easiest, cheapest, and most reliable time source in my situation. I've learned NOT to depend on internet, specially Wifi. OTA tv considerably more difficult and WWV too risky in view of Mr T's recent defunding attempts.
by emma1997
Fri Oct 22, 2021 7:21 pm
Forum: Troubleshooting
Topic: [Solved-ish] (Almost) No Sound
Replies: 30
Views: 1197

Re: [Solved-ish] (Almost) No Sound

This worked for me too. Thanks for that.

One fatal (for me) flaw down and only half dozen or so left to go before attempting another upgrade. lol
by emma1997
Fri Oct 22, 2021 7:16 pm
Forum: Troubleshooting
Topic: Home alarm system with mc-38 reed switch
Replies: 15
Views: 554

Re: Home alarm system with mc-38 reed switch

IME rarely is extra hardware required for clean detection using proper code. Every 1st floor window/door (22 total) in my house has cheapo reed switches. 200' loop and not one failure or false trigger in over 3 decades. I did add a 200r resistor in series more recently but mostly for protection not ...
by emma1997
Fri Oct 22, 2021 6:54 pm
Forum: General discussion
Topic: GPSD users: Time travel bug hitting this weekend
Replies: 32
Views: 1237

Re: GPSD users: Time travel bug hitting this weekend

Ancient Chinese proverb: "Man who choose nasty complex daemon instead of nice simple NMEA string deserve what he get." I've personally been using a cheap GPS modules (Rockwell, Mediatek, Globalsat, finally Ublox) to get time with millisecond accuracy since 1990's. Nanosecond last few years...
by emma1997
Fri Oct 15, 2021 6:37 pm
Forum: Off topic discussion
Topic: agile "technogy" ?
Replies: 25
Views: 1862

Re: agile "technogy" ?

Hard to argue with that. Previous models impressed me as little more than lab exercises but with Pi4, as time goes by I'm more and more impressed with all the effort Pi company puts in to make this a practical personal computer. Specially these 'green-gineers'. BTW my point was with guinea pig custo...
by emma1997
Fri Oct 15, 2021 6:31 pm
Forum: General discussion
Topic: why some posts are locked with unknown reason?
Replies: 13
Views: 873

Re: why some posts are locked with unknown reason?

Using report button to request mod to unlock is the solution. Quite a few have done this so not really a problem. It does make things easier on mods who spend a lot of time dealing with outdated info. However IMO couple years before shutting them down might be better than a few months. Not a disaste...
by emma1997
Fri Oct 15, 2021 6:12 pm
Forum: Troubleshooting
Topic: [Solved-ish] (Almost) No Sound
Replies: 30
Views: 1197

Re: (Almost) No Sound

Just one of the reasons I'm still using last years image. Can't upgrade and newer images are even worse. I suspect there are magic handshakes that fix most of my problems but ATM life is too short to blow hours or days hunting them down. Maybe the new OS version will be better but I'm not holding my...
by emma1997
Fri Oct 15, 2021 6:05 pm
Forum: General discussion
Topic: Two-way data transfer between Pi's over a very long cable
Replies: 53
Views: 2672

Re: Two-way data transfer between Pi's over a very long cable

Two-way communication, with video going one way, controls AND power going the other way, all over 2 wires? Seems almost impossible to me. Tell that to the millions of antenna preamps in the world that send power and receive video using a single coax. Most are motorized too with directional signal b...
by emma1997
Fri Oct 15, 2021 5:46 pm
Forum: Off topic discussion
Topic: agile "technogy" ?
Replies: 25
Views: 1862

Re: agile "technogy" ?

Exactly.

Not directly related to agile but IME many if not most companies use customers as 'beta'. Of course they don't actually use that term or admit to what's really going on. Can be quite a balancing act but definitely the smart way to minimize resources and garner profit.

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