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26

No, you should not increase the voltage any further... and at least this answer linked in the question does not suggest to do that. From Raspberry Pi Power Limitations: Power sources SHOULD provide 5±0.25V ... and: The newer Pi(3/2/B+) have a voltage monitor chip (APX803) which triggers at 4.63±0.07V. The Pi3B+ uses a MxL7704 chip to manage power, ...


16

The MAXIMUM is 5.25V, although this should NOT be the target. You should not apply more than 5.1V That is not to say the Pi will be damaged by the higher voltage, because nothing uses 5V - the on-board regulator supplies the voltages used by the Pi. There is a point when the transient protection diode will trigger - causing the poly fuse to blow. No one ...


10

Use a PoE Hat: Third-party USB-C charging devices can be cheaply wired, potentially destroying connected devices as well as starting fires. A safer alternative is to power your Pi using PoE which beyond reducing these risks, offer additional benefits: Benefits: Using a PoE Hat is easy to setup and enables you to: Emplace a Pi at a much greater distance ...


9

Get a better cable. Most PSUs guarantee the voltage only on the USB-Port. If you use the official Rasperry Pi PSU on the other hand, it guarantees your the voltage on the Micro USB plug. Depending on the used cable this can go way below the USB specifications. I've had cables that dropped 5.25V to as low as 4.7V which already under medium load showed the ...


7

Voltage level The power management IC (PMIC, see section 3) is a MXL7704 with an input voltage range of 4.0 V to 5.5 V and an absolute maximum rating of 6 V that must not be exceeded. Considering that the downstream USB ports are directly connected to the 5 V power rail the 5 V supply should also comply with USB electrical specifications: 4.45 V to 5.25 V ...


7

I will be customizing another power supply manually using voltage dividers You can't do that. And this suggests that you're a novice with electronics. Voltage dividers are fine for signal conditioning or creating a relative reference point for something, e.g. an A/D converter. They are not a way of regulating a power supply. Any modern computer varies its ...


6

Nobody can answer that question as it will be down to the peculiarities of the components in each Pi. As you know 5V +/- 5% (4.75 to 5.25 V) is the USB spec. In your case I suspect your power supply claims more than it delivers. Try a better cable or known truthful supply. That said I have powered higher at 5.8V without causing any known damage. However ...


6

The Pi3B+ can supply up to 1.2A total across the 4 USB ports. See Raspberry Pi Power Limitations. This assumes the Pi power supply is adequate. Whether this would be adequate for 2 SSD drives, depends on the drives. My experience is that the voltage from the USB ports often falls below that required for power hungry external drives, so a powered hub is ...


6

The spec specifically states that: A good quality 2.5A power supply can be used if downstream USB peripherals consume less than 500mA in total. Using a 2.4A power supply with the Pi 4 and a 2.5" HDD is going to be borderline assuming a typical power rating of the 2.5" drive of about 1.8W to 2.7W (see here). From the above statement - after all it really ...


6

The best option is a good quality power supply, as cheap brands may say they are rated at 2.4 amps, when they don't actually supply that much. Based on the numerous bad experiences i've had with 3rd party chargers, i'd highly recommend buying the official one from the foundation! Whether that is adequate for the hard drive is another question. I haven't ...


6

The low voltage indicator is shown when the 5V rail drops below 4.65V. You have to decide whether you trust the Pi's circuitry or the inline USB voltage/amp meter circuitry to correctly see and display transient voltages. The Pi is telling you that you need a better power supply.


5

I don't see that connecting pin 40 (GPIO21, aux SPI SCLK) to ground would have any bad effect. Most GPIO are set as inputs. Connecting an input mode GPIO to ground or 3V3 is normal operation and has no bad effect. If the GPIO was set in output mode and set high then it might damage the GPIO if connected to ground for an extended period. I don't think a ...


5

I did the exact same thing: Shortened the 5V and 3V3 rail by accident (with a probe). In my case it was sufficient to replace the Power-Management-Chip, which is indeed available. I used aliexpress to order it (MXL7704-R3). You will however need a hot air rework station. A cheap one as in my case will do, but a simple hot air blower from the hardware ...


5

As far as I know, you can not disable only one USB. When you turn USBs power off, also the Ethernet port turned off. I don't know if there is a way to disable USB/Ethernet in config.txt, but in cmd line you can do it with: echo '1-1' |sudo tee /sys/bus/usb/drivers/usb/unbind To enable the ports use: echo '1-1' | sudo tee /sys/bus/usb/drivers/usb/bind ...


4

TL;DR The external hard drive is powering the RPI after you remove the microUSB power supply. This is called Backfeeding. This is not unusual for raspberry pi's. Is it bad for the pi I would advise against backfeeding because there is little protection for the Pi. You would need to ensure there is a stable voltage and current to avoid damage. I would ...


4

How can we tell apart 3rd party chargers that would work with RPi4? You can either rely on reviews or ask the seller and take their word for it, or you can get the supply, test it, and return it back if it doesn't perform. Obviously, in the latter case you'll want to buy it from a place where you can return it for free. There is no way to tell from the ...


4

Question For connecting two USB SSD/HDDs, does an Rpi USB Hub need any external power? Short Answer Update for Rpi4B buster 2020apr16 Soon after my 2019jul answer below, I upgraded from Rpi3B+ to Rpi4B, with 1/2/4G RAM, and successive releases of buster (now Release 2020feb). I am happy to update my SSD report that so far as good. I measured the ...


4

This is an exercise in futility! Disabling devices will make very little difference in power usage, which is mainly determined by processor load. About the ONLY device which will have any affect is WiFi. You should consider a Pi3A+ which has lower consumption and no USB hub or Ethernet.


4

I actually just found out the answer -- it's somehow not yet implemented on the Raspberry Pi 4. The command still works on all previous Raspberry Pi devices. Since it seems to be rather difficult to find the page that even mentions this command, I'll link it as follows: Video Options in config.txt If anyone has comments on why it wouldn't be implemented yet,...


4

You will not find a specification, because there isn't one. The Pi4 has the same power manager as the Pi3B+ and Pi3A+ so the current limitation would be the same (the PMIC is rated at 1.5A). The Pi3 regulator is rated at 1A and has been tested at 800mA (on 3.3V). There is no polyfuse or limitation on 5V, so you could in principle draw up to the limit of ...


4

EDIT NOTE: This is a completely revised answer as my original answer was completely wrong! I deleted the answer when this was called to my attention; I have just "un-deleted" it since revising my answer. Without further ado, here is the revised answer: Incorrect answer: It will work. Here's the math: RPi 4 current requirement: 2.5 A (per the org's spec ...


4

The GPIO on a RPi are 3.3Vdc. If you are using this to drive a 5Vdc coil on a relay, then this is most likely the source of your issues. Relay coils have several specifications including the minimum required current to switch over the contacts, coil holding current (current required to hold the contact's state), and drop out voltage which is the voltage at ...


4

Despite your unreferenced comment about online posts (you can find lots of flat earth posts if you look) there is no mystery - it is well documented. I am surprised you find engineers at the Raspberry Pi Foundation not authoritative. See https://raspberrypi.stackexchange.com/a/100234/8697 Unfortunately due to lobbying by a lot of luddites who had designed ...


4

"Is this known behavior?" This is common for poor supplies and/or inadequate cables. The warning is for transient undervoltage - you can't measure with any kind of DMM. Trying to compensate by increasing voltage is likely to damage the Pi. Use an official supply


4

First of all: you are running Raspbian Stretch but tagged the question with pi-4. This is not possible. A Raspberry Pi 4B can only run Raspbian Buster. Your timer Unit looks good and should do. But you define some default settings that are not necessary. This normally should not do any harm, but having problems it's always a good idea to configure with ...


3

The Pi has 3 "components" the CPU, GPIO and Video Core which are relatively independent. Even when the Pi is shutdown the Video Core continues to run, and the GPIO pins retain their state; only the CPU is not running. The 3.3V is supplied by separate circuitry and will be present while ever the Pi is connected to a 5V supply. The best way to reliably ...


3

This howchoo post shows how to connect an LED to show the status of the Pi. The LED is steady on when the Pi is running, and off after shutdown. Briefly: Add this line to /boot/config.txt, and reboot enable_uart=1 Connect the TxD pin (GPIO pin 8) to the positive lead of a 2 or 3 volt LED. Connect a ground pin (e.g. GPIO pin 6) to a 330 ohm resistor, ...


3

not able to power ... from a Raspberry pi 3 Here's why: Pi 3 was designed with USB 2.0 specs, including the 0.5 amp limit. Most hard drives require more current than that. Raspberry Pi 4 has USB 3.0, which means it is designed to supply up to 1 amp. That is likely enough to run the hard drive.


3

The (native) ext4 filesystem is said to be robust with respect to power outages (ref.). I'd guess that file system corruption due to a shortcoming of ext4 is less likely than random corruption of your SD card. If that's true, consider spending a bit more for a high-quality SD card & don't worry too much about tweaking the filesystem. Maintaining a good ...


3

Answer As per the comments of @joan and @theashwwanisingla I tested the module/sensor and there is 0 resistance between the + and - pins. So this is simply a broken piece of hardware. References (1) DHT11 Temperature and Humidity Sensor User Manual - Components 101 2018jan05 (2) DHT11 Temperature and Humidity Module Datasheet - AoSong (3) DHT11 Setup ...


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