4

This is a JTAG connector used for development and testing. Here's a picture of an old Pi B+ featuring the signal names printed on it: AFAIK it's useless unless you have VideoCore documentation and tools from Broadcom.


4

The most likely cause for BS270 (or any n-channel JFET) to continue conducting is, as you said, "G leg not connected to anything". The capacitance in the Gate junction stores a charge created when you turned the LED "ON". You should be able to drain the charge by connecting a resistor between the Gate junction and Ground - as shown in the ...


2

Any GPIO which is not connected to a voltage will float between high and low. You need to give the GPIO a fixed voltage by supplying a pull to 3V3 or a pull to ground. The weak internal pulls (about 50kohm) can easily be overcome by noise. Try adding an external pull of around 5kohm or lower until the GPIO is stable in your environment.


2

What sort of frequencies are you talking about? pigpio can do this with waves (hardware timing). E.g. http://abyz.me.uk/rpi/pigpio/examples.html#Python_wavePWM_py My new lg library can do this using software timed PWM. E.g. Python http://abyz.me.uk/lg/py_lgpio.html#tx_pwm pigpio example using pigs (command line) G1=12 G2=13 OFFSET=500 B1=$((1<<$G1)) B2=...


1

It's fine to leave it connected, but the power consumption of the Pi may not be what you expect it to be. Unless WAKE_ON_GPIO is set to 0, and POWER_OFF_ON_HALT is set to 1 in the bootloader config, the Pi will still consume a lot of power.


1

In my younger years (long before microprocessors) I spent some time working on automotive electronics. This is a HOSTILE environment - motorcycles are an order of magnitude worse. It is possible BUT is somewhat a specialist field. You NEED an isolated supply, extensive shielding, all inputs should ideally be galvanically isolated and any connections need ...


1

It's not clear from your question that you need to measure current. As a practical matter, measuring voltage is often easier. @Dougie comment suggesting an [opto-coupler (a.k.a. opto-isolator)] is a good one as it provides galvanic isolation - an important safety consideration working with mains voltages. As you've seen in the comments, there are various ...


1

AWG = "American Wire Gauge" is a standard for the thickness of wire (check Wikipedia). AWG 22 is equivalent to a wire surface of about 0.3 mm^2. That's fine to be used in breadboards. If you don't need to transmit a lot of power, that should be fine. If you use it also for the power lines, you might need thicker wire or take several wires for ...


1

If I understand your objectives correctly, it seems that your idea is generally sound. But, the devil is in the details as they say. Reviewing your diagram: It appears that the purpose of the Low Battery Cutoff Switch and the N.O. 12 V Relay is to signal the RPi (via GPIO input) that it should execute a shutdown soon. However, 12.3V seems too high for a low-...


1

Is it possible to replace it to save this rpi? Maybe... But it is literally impossible for anyone here (remote, no hands-on) to tell you if your board is repairable or not. I don't know if the odds improve significantly if we were "hands-on". All you can do is try replacing the component that you blew off the board, and see what happens. The RPi ...


1

After spending ~ 20 min searching for an actual data sheet on the SH5461AS - and not finding one - I'm of the opinion this is JAPCJ (just another piece of Chinese junk). My best advice is chuck it in the bin & find a part by a reputable manufacturer. There are lots of manufacturers that publish spec sheets (even on parts as old as this one) - here's an ...


1

What you are missing is a specification: "How much current does your LED Tinsel require to operate?" Give us that info, and we can give you a definitive answer - without it, we have to guess - and that's a waste of everybody's time, no? I Guess: The GPIO pin can not supply enough power to drive your LED Tinsel. You can do some research on that. ...


1

When the GPIO pin is set to OUT mode, it can be in two states, LOW or HIGH. Have you put your pin into HIGH state? If yes, then it's possible that the GPIO doesn't provide enough current to power a LED tinsel.


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