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by mangiari
Mon Mar 04, 2019 6:17 am
Forum: Troubleshooting
Topic: Pi Zero W 1.1: vcgencmd get_throttled returning 0x0 although input voltage below 4V??
Replies: 6
Views: 489

Re: Pi Zero W 1.1: vcgencmd get_throttled returning 0x0 although input voltage below 4V??

Thanks a lot for clarifying, already ordered a LiIon-protection board.
by mangiari
Sun Mar 03, 2019 1:27 pm
Forum: Troubleshooting
Topic: Pi Zero W 1.1: vcgencmd get_throttled returning 0x0 although input voltage below 4V??
Replies: 6
Views: 489

Re: Pi Zero W 1.1: vcgencmd get_throttled returning 0x0 although input voltage below 4V??

Is this for sure with the missing low voltage detection? Can somebody else confirm that?

If it is like that, I think I'll have to go for an external battery protection circuit.
by mangiari
Sun Mar 03, 2019 8:33 am
Forum: Python
Topic: reading the output of vcgencmd get_throttled and trigger shutdown, when != 0
Replies: 4
Views: 1013

Re: reading the output of vcgencmd get_throttled and trigger shutdown, when != 0

Thanks for the detailed reply, and I'm very sorry not having answered back then, I did not get to the pi for all that time. Now I wanted to get back to the issue and found something else: My vcgencmd get_throttled is never giving anything else than 0x0, no matter what the input voltage is. So I firs...
by mangiari
Sun Mar 03, 2019 8:30 am
Forum: Troubleshooting
Topic: Pi Zero W 1.1: vcgencmd get_throttled returning 0x0 although input voltage below 4V??
Replies: 6
Views: 489

Pi Zero W 1.1: vcgencmd get_throttled returning 0x0 although input voltage below 4V??

From what I found in this forum , the raspberrypi seems to set some bits when the input voltage drops below 4.6V. The way it was written I thought I can rely on that for a low voltage shutdown to safe my LiIon cells from deep discharge. Now when I wanted to write the code for that (shutdown pi as so...
by mangiari
Sat Feb 02, 2019 10:43 am
Forum: Python
Topic: reading the output of vcgencmd get_throttled and trigger shutdown, when != 0
Replies: 4
Views: 1013

reading the output of vcgencmd get_throttled and trigger shutdown, when != 0

I need a python snippet, that reads in the value from vcgencmd get_throttled parses this into a variable that bitmask comparisons can be done. Sounds like a pretty trival one liner, but I'm really new to python and the syntax. I already have a python script in my project, that checks GPIO inputs and...
by mangiari
Sun Jan 20, 2019 6:24 am
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

Re: battery powered pi, implement real power button?

So, now finally I got a working circuit: smallAmpCircuit.png I had to take optocouplers, to get rid of the 3.3V vs. 5V problems and also the common ground trouble with the MOSFET, described in the comments above. This is how it works: In the top left corner is the L4940V5, a low drop 5V regulator. I...
by mangiari
Tue Jan 08, 2019 4:29 pm
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

Re: battery powered pi, implement real power button?

So all tries with MOSFET and bipolar transistors ended up in the same dead end... I updated the circuit image to avoid people trying to use it (or parts of it). In the end I found a pretty simple and elegant way of working around that ground and high pin problems: Put the raspberry in a nutshell and...
by mangiari
Tue Jan 08, 2019 4:23 pm
Forum: Advanced users
Topic: How to detect shutdown state?
Replies: 9
Views: 2625

Re: How to detect shutdown state?

If you don't have the raspberry pi in the positive side of the MOSFET, it will not be able to switch the MOSFET active. The raspberry pi needs to have potential above the source potential of the MOSFET to be able to drive it active. The same problem occurs when using bipolar transistors as switch. B...
by mangiari
Sun Jan 06, 2019 2:17 pm
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

Re: battery powered pi, implement real power button?

Yes thanks for the tips. The 5V regulator is needed, because the 7.2V of the battery pack can become more than 8V when charging and less than 6.5V when battery gets low. This is far too much spread for any other solution. I can live with the raspi between 4.6 and 5.6V but not more. But as you can se...
by mangiari
Sat Jan 05, 2019 11:14 pm
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

Re: battery powered pi, implement real power button?

Yes well, it sounds ok, but then I have no clue about that simple microcontrollers. I did some arduino projects, but you don't get them for a bug. And I don't have that much space in my device. I can't believe that there is no simple way with discrete implementation. After having trouble with the ci...
by mangiari
Sat Jan 05, 2019 11:06 pm
Forum: Device Tree
Topic: Confirmation of gpio-poweroff Behavior
Replies: 19
Views: 18940

Re: Confirmation of gpio-poweroff Behavior

I'm very much interested in the P-channel idea. Currently I'm trying to shut off the power from my raspi with a N-channel MOSFET and have really severe trouble. I managed everything internal, so I have the pins that go high, holding the MOSFET Gate (which was initially activated by a pushbutton and ...
by mangiari
Fri Jan 04, 2019 12:56 am
Forum: Advanced users
Topic: How to detect shutdown state?
Replies: 9
Views: 2625

Re: How to detect shutdown state?

Unfortunately the setup as I tried it does not work. The configured GPIO-pin goes low after shutdown, it was the one that holds the MOSFET active, so that the raspberry had power, but at the moment the power is disconnected (actually just the negative power supply gets a high resistor against the re...
by mangiari
Fri Jan 04, 2019 12:48 am
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

Re: battery powered pi, implement real power button?

Puuh, that 3.3V / 5V stuff with the raspberry pi is really driving me nuts. The 3.3V voltage regulator with it's ground connected to the somehow floating ground of the pi's power supply does all kind of funky things. I first thought my MOSFET might be burnt or something, but in the end when I remove...
by mangiari
Thu Jan 03, 2019 2:24 am
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

Re: battery powered pi, implement real power button?

My project is a music jukebox for a small kid. The pi sits very sheltered in a wooden case and there is no GUI to call shutdowns from. Only software that plays music depending on GPIO button pushs... @rzusman: Wow, that sounds like a little bit more than minimum necessary parts. I have a similar pro...
by mangiari
Thu Jan 03, 2019 1:56 am
Forum: Advanced users
Topic: How to detect shutdown state?
Replies: 9
Views: 2625

Re: How to detect shutdown state?

As I mentioned, for my personal project the behavior after shutdown is not relevant, as soon as this shutdown GPIO-Pin goes low, the MOSFET will switch off the power from the raspberry pi. And it's a zero 1.3 in my case.
by mangiari
Tue Jan 01, 2019 10:20 pm
Forum: Advanced users
Topic: How to detect shutdown state?
Replies: 9
Views: 2625

Re: How to detect shutdown state?

Hey thanks, that's exactly what I'm looking for. After your hint, I found this Thread about the same issue and questions, which helps a lot! I added dtoverlay=gpio-poweroff,gpiopin=4,active_low=1 to my /boot/config.txt and gpio4 now goes high at the moment I connect the USB and it goes back to low a...
by mangiari
Tue Jan 01, 2019 7:19 pm
Forum: Advanced users
Topic: How to detect shutdown state?
Replies: 9
Views: 2625

How to detect shutdown state?

Is there an easy clean way to get a signal (preferably a low on an else wise high gpio pin) when a raspberry pi halted completely and is safe to be cut off from the power supply? I found this power led tutorial but the serial pins don't seem to be a solid on/off indicator when it comes to switching ...
by mangiari
Tue Jan 01, 2019 5:00 pm
Forum: HATs and other add-ons
Topic: battery powered pi, implement real power button?
Replies: 12
Views: 4742

battery powered pi, implement real power button?

Not sure whether I'm in the right board, feel free to move it whereever it belongs. I already did a battery powered project with an arduino, that is working great with a mosfet giving the power supply to the arduino board. A pushbutton momentarily gives positive battery voltage to the gate, powering...
by mangiari
Tue Jan 01, 2019 4:39 pm
Forum: Troubleshooting
Topic: [Solved] Raspberry pi zero w with wifi trouble, how to locate exact problem?
Replies: 1
Views: 1098

[Solved] Raspberry pi zero w with wifi trouble, how to locate exact problem?

Edit: Playing around in the raspi-config with the connected keyboard somehow I got it running. I enabled predictable network interface names and re entered the WIFI credentials. No clue what actually was the problem. -------------- original problem: Hi there, I have a raspberry pi zero w here that s...
by mangiari
Fri Sep 07, 2018 8:12 am
Forum: General discussion
Topic: USB Powerbank that does not switch off when idle?
Replies: 4
Views: 2066

Re: USB Powerbank that does not switch off when idle?

I have noticed that most powerbanks need a minimum load to turn on and stay on. In one case I connected some resistors to draw 100mA and that activates the powerbank and keeps it on. Can you send the exact details, which powerbank that was? While all my powerbanks keep providing voltage, when some ...
by mangiari
Fri Sep 07, 2018 6:58 am
Forum: HATs and other add-ons
Topic: problems with pHAT BEAT - direct current at speaker terminals
Replies: 24
Views: 3871

Re: problems with pHAT BEAT - direct current at speaker terminals

My point is, that the discussion tends to speculating about whether the magic IC might be able to pump high frequency alternating current through a resistor as if it had no ohmic resistance or it might have trouble with four speakers with 4 ohm in series, instead of one speaker with 16ohm. I'm prett...
by mangiari
Thu Sep 06, 2018 8:04 am
Forum: HATs and other add-ons
Topic: problems with pHAT BEAT - direct current at speaker terminals
Replies: 24
Views: 3871

Re: problems with pHAT BEAT - direct current at speaker terminals

Brandon92 wrote:
Wed Sep 05, 2018 8:08 pm
It could be very possible that 4 speakers are to much for the driver. This means also that you have 4 "inductors" in serie.
I think you should refresh your knowledge about the Kirchhoff's circuit laws, before you continue spreading claims like that.
by mangiari
Wed Sep 05, 2018 2:34 pm
Forum: General discussion
Topic: USB Powerbank that does not switch off when idle?
Replies: 4
Views: 2066

USB Powerbank that does not switch off when idle?

I built several small gadgets with raspberrys and arduinos. All of them have the possibility to turn themselves off, when idle, to be able to run them on battery for a long time. So the power is supplied through a MOSFET, that is initially set conducting by the power switch and at the moment the boa...
by mangiari
Wed Sep 05, 2018 2:18 pm
Forum: HATs and other add-ons
Topic: problems with pHAT BEAT - direct current at speaker terminals
Replies: 24
Views: 3871

Re: problems with pHAT BEAT - direct current at speaker terminals

Thanks for the long constructive answer Brandon! I did not get any time on the issue/project, that why I did not reply for such a long time. To get back to your problem What I did now: I connected 4 speakers in series to one of the terminals, with a combined measured ohmic resistence of about 15 Ohm...
by mangiari
Tue Aug 28, 2018 10:08 pm
Forum: HATs and other add-ons
Topic: problems with pHAT BEAT - direct current at speaker terminals
Replies: 24
Views: 3871

Re: problems with pHAT BEAT - direct current at speaker terminals

BTW: If I look at the tutorial for soldering at the manufacturer site , it looks to me like they expect absolute newbies to be able to put the stuff together. So I would expect the boards not to malfunction after some one or two seconds of soldering per pin. In fact there is nothing but SMD resistor...

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