[Guide] Graceful shutdown switch without Pololu [RETIRED]

[BigOlTexasBoy]

Regarding the tutorial it should be an 2n5460 JFET transistor. Don't know if you've misstyped it (two times) or got the wrong.

It works. I've talked to Camble about that. There are other transistors that work as well. I'm just hoping all the wires are going to the right places.

[Camble]

@alien0matic The 47k resistor and 2N3904 transistor refers to @Popcorn's low battery interface from the PowerBoost's low battery LED.

@BigOlTexasBoy You are right to say the 2N5461 will work, as the 2N546x series are pretty much the same, just with different Gate-Source cut-off voltages.

Your diagram looks correct to me.

The 2N3904 will not work for this circuit as it is a regular transistor, and not a depletion type FET.

[BigOlTexasBoy]

The 2N3904 is for Popcorn's Low Battery Monitor. That is what he has listed in the forum. Did it change?

[Camble]

@BigOlTexasBoy No, just clearing up any confusion.

[BigOlTexasBoy]

@BigOlTexasBoy No, just clearing up any confusion.

Thanks. I can't believe I finally figured this out.

[RxBrad]

Was on vacation for the last week, so I'm a bit late to the discussion. I wired up my DMG switch like so (based on schematics from a couple weeks ago), and finally got it hooked up:



The on & off positions appear to be switched, and when I power off the switch, it just instantly cuts power rather than doing a proper shutdown.

[Camble]

@RxBrad Are you sure the pinout of your JEFT is correct?

[edit] Nevermind, I forgot your pinout was different.

[RxBrad]

Was on vacation for the last week, so I'm a bit late to the discussion. I wired up my DMG switch like so (based on schematics from a couple weeks ago), and finally got it hooked up:



The on & off positions appear to be switched, and when I power off the switch, it just instantly cuts power rather than doing a proper shutdown.

So, I switched the on/off pairs on the switch, and the on & off positions now act how I'd expect.

I also reworked the circuit so the resistor bridged Drain/Gate instead of Source/Gate (bridged where I previously cut the copper strip, and cut the jumper wire between Drain/Source). When I flip the switch off, it still insta-kills the power.

I double checked my config.txt, and I made the recommended change to Popcorn's low power monitor script.

Kind of stumped at this point. Maybe I'll just rebuild using a non-DMG switch.

[Camble]

@RxBrad Sounds like you have a similar issue to @Popcorn. He is using a Motorola brand 2N5460 JFET and it just doesn't seem to like him.

[RxBrad]

@RxBrad Sounds like you have a similar issue to @Popcorn. He is using a Motorola brand 2N5460 JFET and it just doesn't seem to like him.

Going back through the thread, it appears that @Popcorn eventually got it working... I wonder how he managed that?

So far, my Fairchild-branded JFET (purchased from Jameco) appears to be a no-go.