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by sparkyhall
Fri Aug 14, 2020 10:00 pm
Forum: General discussion
Topic: RPi 4 12V pwm fans - Schematic
Replies: 16
Views: 788

Re: RPi 4 12V pwm fans - Schematic

Assuming the fans you have can be controlled by PWM the diode seems unnecessary and as drawn is round the wrong way. The circuit you have drawn will do nothing.
by sparkyhall
Tue Aug 04, 2020 7:29 am
Forum: General discussion
Topic: Pi4 won't boot with GPIO connections (lcd display) after wire mix up
Replies: 11
Views: 464

Re: Pi4 won't boot with GPIO connections (lcd display) after wire mix up

The LCD in the pictures includes a parallel to I2C converter board, the board with the potentiometer. You cannot connect this variant of the LCD to the Pi the way you have as the LCD is intended to be connected using the 4 pins on the converter board. I believe that this LCD is designed to be powere...
by sparkyhall
Mon Aug 03, 2020 6:50 am
Forum: General discussion
Topic: Pi4 won't boot with GPIO connections (lcd display) after wire mix up
Replies: 11
Views: 464

Re: Pi4 won't boot with GPIO connections (lcd display) after wire mix up

If the Pi works OK with nothing connected to the GPIO then this suggests that the Pi is fine and the problem is with the items you are connecting to the GPIO. A picture of your connections and a link to the LCD and potentiometer would be helpful here otherwise we are just guessing. If you are using ...
by sparkyhall
Tue Jun 02, 2020 6:29 am
Forum: General discussion
Topic: latest stable EEPROM has problems w/ Moitessier hat 2
Replies: 6
Views: 580

Re: latest stable EEPROM has problems w/ Moitessier hat 2

I'm not sure how to roll back to previous a kernel as I tend to keep back-ups. Assuming you are using Raspberry Pi OS (formally Raspbian) to stop a package from updating you use "sudo apt-mark hold <package-name>". So to stop the boot loader and kernel updating you would use: sudo apt-mark hold rasp...
by sparkyhall
Mon Jun 01, 2020 12:23 pm
Forum: General discussion
Topic: latest stable EEPROM has problems w/ Moitessier hat 2
Replies: 6
Views: 580

Re: latest stable EEPROM has problems w/ Moitessier hat 2

I think you have this the wrong way round. From rooco web site it looks like the drivers for the Moitessier hat are tied to a specific kernel version so it's no wonder it breaks when the kernel is updated. You need to contact rooco and ask them to update their drivers or you can have a go compiling ...
by sparkyhall
Mon May 25, 2020 7:51 am
Forum: General discussion
Topic: Can you paste files onto the raspberry pi instead of flashing them?
Replies: 16
Views: 727

Re: Can you paste files onto the raspberry pi instead of flashing them?

If for example I have some partition, I'm backing up all the files in there, deleting it and then recreating that same partition and pasting the original files, after modifying the cmdline/fstab accordingly, should it work? Thanks. Yes, providing you maintain the correct file attributes such as own...
by sparkyhall
Sun Apr 26, 2020 8:59 am
Forum: RISCOS
Topic: Complete beginner - buying a Raspberry Pi and running riscOS
Replies: 4
Views: 1040

Re: Complete beginner - buying a Raspberry Pi and running riscOS

I'd forget about plugging a floppy drive in, that's not going to be at all easy.

You also need a wired network connection as wifi is not plug and play on Riscos unlike on more modern systems.
by sparkyhall
Sat Apr 25, 2020 7:51 am
Forum: General discussion
Topic: Free space problem
Replies: 5
Views: 474

Re: Free space problem

Did you remember to tell ncdu to start at the root directory?

Code: Select all

ncdu -x /
The -x is not necessary but it stops ncdu crossing file system boundaries, for example, if you have a USB drive plugged in.
by sparkyhall
Sun Mar 22, 2020 10:01 am
Forum: General discussion
Topic: Getting £ instead of # on keyboard
Replies: 2
Views: 246

Re: Getting £ instead of # on keyboard

The default keyboard layout is for the UK so I guess you failed to set the keyboard layout when you first booted. On a UK keyboard the # key is next to the enter key, see here: https://en.wikipedia.org/wiki/British_and_American_keyboards Once you are in you can set the keyboard layout through the co...
by sparkyhall
Wed Mar 18, 2020 4:33 pm
Forum: General discussion
Topic: Raspbian without preinstalled software
Replies: 11
Views: 741

Re: Raspbian without preinstalled software

You can install command line file managers such as midnight commander (mc).
by sparkyhall
Sat Feb 22, 2020 8:43 am
Forum: General discussion
Topic: MOSFET vs BJT for Pi Relay Circuit
Replies: 8
Views: 826

Re: MOSFET vs BJT for Pi Relay Circuit

You seem to have omitted the flywheel/flyback diode across the relay coil, without this you are allowing the back emf to rise to an uncontrolled level which is why you see the high voltage transient during switch off. You can probably get away with this with small relays like the one you have used b...
by sparkyhall
Wed Feb 19, 2020 6:26 pm
Forum: General discussion
Topic: Putty Not Connecting(SSH enabled)
Replies: 3
Views: 237

Re: Putty Not Connecting(SSH enabled)

Have you checked that the ssh demon is running on the pi? To do this open a terminal on the pi and enter the following at the command prompt: ps aux | grep ssh and you should see something like this: root 544 0.0 0.1 10724 5376 ? Ss 16:33 0:00 /usr/sbin/sshd -D chris 951 0.0 0.0 4520 288 ? Ss 16:33 ...
by sparkyhall
Wed Feb 19, 2020 6:20 pm
Forum: General discussion
Topic: Email server for local network
Replies: 3
Views: 303

Re: Email server for local network

Although not specifically for Raspian or the Pi this guide looks like it should work:

https://gist.github.com/raelgc/6031274

Note: I've not tried this myself yet but I plan to in the very near future.
by sparkyhall
Wed Jan 01, 2020 2:25 pm
Forum: Troubleshooting
Topic: RPi4 poweroff - still on?
Replies: 14
Views: 1402

Re: RPi4 poweroff - still on?

The default boot loader config was changed some time ago so that the 3V3 now remains on after a system halt because some hats did not like having a 5V supply without 3V3. You can change back to the previous behaviour by changing the defaults for "WAKE_ON_GPIO" and "POWER_OFF_ON_HALT", for details se...
by sparkyhall
Tue Dec 31, 2019 4:28 pm
Forum: Troubleshooting
Topic: what would happen if wire a 5V battery to the 5VDC gpio pins of a rasbary pi 4
Replies: 12
Views: 760

Re: what would happen if wire a 5V battery to the 5VDC gpio pins of a rasbary pi 4

Are there extra procedures to prevent the pi from shorting You can use a Fuse or a Polyfuse for protection if you feed Power into GPIO. This need a Step-Down or a Step-Up Converter cause the floating voltage of batterys. You can for example use 6x 1.2V and feed this into XL4015 then into the Raspbe...
by sparkyhall
Wed Dec 25, 2019 5:28 pm
Forum: Troubleshooting
Topic: RPi 4 doesn't shutdown completely
Replies: 4
Views: 710

Re: RPi 4 doesn't shutdown completely

The default boot loader config was changed some time ago so that the 3V3 now remains on after a system halt because some hats did not like having a 5V supply without 3V3. See "WAKE_ON_GPIO" and "POWER_OFF_ON_HALT" in the following link: https://www.raspberrypi.org/documentation/hardware/raspberrypi/...
by sparkyhall
Mon Dec 16, 2019 9:03 pm
Forum: General discussion
Topic: Device not detected using i2c-detect y 1
Replies: 13
Views: 881

Re: Device not detected using i2c-detect y 1

3V3 pin to HDMI_metal shell = 3.3V is Correct 3v3 pin to Gnd = -1.79 suggests that your gnd is connected to 5V 5v0 pin to HDMI_metal shell = 0v suggests that your gnd is connected to 5V 5v0 pin to Gnd = 5v is correct and contradicts the readings above? It think it is time to check the continuity bet...
by sparkyhall
Sun Dec 15, 2019 9:03 am
Forum: General discussion
Topic: Doesn't the Raspberry case disturb the wifi signal?
Replies: 3
Views: 924

Re: Doesn't the Raspberry case disturb the wifi signal?

Yes, a metal case can have a negative impact on the WiFi signal. Given the number of variables (distance from router/AP, number of nearby routers in your area etc) it's not possible to say if this will be a problem for you. To give you an idea here is a link to a review of the Argon Neo with WiFi re...
by sparkyhall
Sun Dec 08, 2019 8:29 am
Forum: General discussion
Topic: Device not detected using i2c-detect y 1
Replies: 13
Views: 881

Re: Device not detected using i2c-detect y 1

With the sensor unplugged, the voltage measurement is 3.36v. When wired as shown below the voltage is 0.57v It's not going to work if the 3V3 measures 0.57V at the BME280, this is the area we need to focus on. What supplies the 3V3, is the Raspberry Pi or something else? What happens to the Raspber...
by sparkyhall
Mon Nov 25, 2019 9:45 am
Forum: General discussion
Topic: GPIO connection with ATmega328p
Replies: 9
Views: 601

Re: GPIO connection with ATmega328p

It'll be fine, just keep connecting cables as short as possible, I would go for < 150mm.
by sparkyhall
Mon Nov 25, 2019 8:48 am
Forum: General discussion
Topic: GPIO connection with ATmega328p
Replies: 9
Views: 601

Re: GPIO connection with ATmega328p

If you have configured the GPIO for internal pull-down then there is no need for the external pull-down resistors. The only thing you need to consider is is the internal 50k(ish) pull-down is enough for your use case.
by sparkyhall
Sun Nov 24, 2019 10:34 pm
Forum: Advanced users
Topic: DVFS Firmware
Replies: 89
Views: 16862

Re: DVFS Firmware

I just had a hard lock on mine after just over 2 hours of use., never done this before and I have been using this a few hours a day since July. This was with CPU overclock = 1800MHz and overvolt=2.

Will drop to default clock and overvolt and see how it goes.
by sparkyhall
Sun Nov 24, 2019 8:39 pm
Forum: Advanced users
Topic: DVFS Firmware
Replies: 89
Views: 16862

Re: DVFS Firmware

DVFS firmware working fine here. I normally run with a CPU overclock of 1800MHz and overvolt=2, this works fine with DVFS although I get 5 frequency steps (600, 720, 900, 1200 & 1800) I assume this is correct? The idle power consumption at the mains plug is now 3.0W instead of 3.3W, that's a 10% red...
by sparkyhall
Wed Nov 20, 2019 8:21 pm
Forum: General discussion
Topic: Thunder activated
Replies: 5
Views: 583

Re: Thunder activated

As others have suggested, detecting lightning may be the way to go. You can buy ready made break out boards for this, such as this one: http://www.embeddedadventures.com/as3935_lightning_sensor_module_mod-1016.html I have had one these for about a year and I plan to attach this to my Pi based weathe...
by sparkyhall
Sun Nov 10, 2019 9:00 am
Forum: General discussion
Topic: What is the maximum temperature of the CPU before it gets demaged ?
Replies: 21
Views: 2578

Re: What is the maximum temperature of the CPU before it gets demaged ?

Board orientation makes a difference, vertical seems best for cooling and I recall jahboater saying his was vertically mounted.

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