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by RGJ-PI
Fri Jan 10, 2020 4:19 pm
Forum: Other projects
Topic: Powering PI from alarm panel, enough amperage?
Replies: 5
Views: 170

Re: Powering PI from alarm panel, enough amperage?

You can set it to 5.1V to allow for a bit of Voltage drop from the PSU to the Pi. Obviously set the Voltage before you connect the Pi. Once running you could always trim the Volts setting by measuring the 5V on the Pi GPIO header
by RGJ-PI
Fri Jan 10, 2020 11:06 am
Forum: AIY Projects
Topic: Voice Hat v1 button led using LED strip instead of the button
Replies: 2
Views: 215

Re: Voice Hat v1 button led using LED strip instead of the button

Looking at the J14 header, the LED Voltage (5V) is on pin 2. Pin 1 is pulled to ground by the 5A capable MOSFET (Q7). This can be presumably PWM modulated for brightness using the LED_GPIO line. You are correct that just connecting a LED across pins 1 and 2 of the header would most likely damage the...
by RGJ-PI
Thu Jan 09, 2020 3:12 pm
Forum: General discussion
Topic: VM-61 RFID
Replies: 1
Views: 75

Re: VM-61 RFID

Well you'll need to refer to the module data sheet (which I haven't found with a quick Google search) for hardware connection and comms protocol requirements but looking at the table you've posted I'd imagine you'd be best talking to it over the UART_RXD and UART_TXD pins to the UART pins on the Pi ...
by RGJ-PI
Wed Jan 08, 2020 4:22 pm
Forum: Troubleshooting
Topic: Installing the latest Arduino IDE
Replies: 3
Views: 97

Re: Installing the latest Arduino IDE

Try using the 32bit version from the same download page you linked instead of 64bit.
by RGJ-PI
Tue Dec 24, 2019 11:48 am
Forum: Ubuntu
Topic: Ubuntu-mate doesn't boot
Replies: 2
Views: 235

Re: Ubuntu-mate doesn't boot

If you can't boot to re-enable it then you can edit the config file directly. You can put the SD Card in a reader connected to a PC. Only the boot partition will show and obviously ignore any requests to format the unrecognised partition. Find the file config.txt and open. At the end of the file you...
by RGJ-PI
Mon Dec 23, 2019 2:34 pm
Forum: Troubleshooting
Topic: Hardware Problem with HDMI port
Replies: 10
Views: 357

Re: Hardware Problem with HDMI port

The differential HDMI signals are direct connects to the main Broadcom chip via the four small common mode chokes you can see in your photo. Even if we published schematics beyond those James has linked to you'd only see the ball numbers for the Broadcom chip so wouldn't be much help.
by RGJ-PI
Mon Dec 23, 2019 1:22 pm
Forum: Troubleshooting
Topic: Hardware Problem with HDMI port
Replies: 10
Views: 357

Re: Hardware Problem with HDMI port

With the Voltages you showed I was hoping that it might have been an issue with the HDMI detect but your latest measurements show that not to be the case. Unfortunately it could well be that the HDMI circuitry within the main chip could well have been damaged in the original issue that took out the ...
by RGJ-PI
Mon Dec 23, 2019 12:00 pm
Forum: Other projects
Topic: Water temperature and pump control for pond - how?
Replies: 3
Views: 348

Re: Water temperature and pump control for pond - how?

Don't forget to add some hysteresis to your switching, ie switch pump off when water temp goes down to 2c, switch pump back on when water temp reaches 3c or something similar. You don't want the pump rapidly switching off and on if the water temp is at the transition point.
by RGJ-PI
Mon Dec 23, 2019 10:00 am
Forum: Troubleshooting
Topic: Hardware Problem with HDMI port
Replies: 10
Views: 357

Re: Hardware Problem with HDMI port

The pin you measured 3.25V on (next to the H of HDMI) should either be at 0V (when a monitor is plugged into the HDMI socket) or pulled up to 3V3 when monitor not connected. Have you got a different HDMI cable you could try?
by RGJ-PI
Fri Dec 20, 2019 7:37 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3 Model B+ and POE Pi Hat
Replies: 5
Views: 129

Re: Raspberry Pi 3 Model B+ and POE Pi Hat

That at least rules out the PoE hat then. Are you seeing any access points shown when click on the wifi task bar icon near the clock?
by RGJ-PI
Fri Dec 20, 2019 12:54 pm
Forum: Troubleshooting
Topic: Raspberry Pi 3 Model B+ and POE Pi Hat
Replies: 5
Views: 129

Re: Raspberry Pi 3 Model B+ and POE Pi Hat

It's an unusual use case but yes you can use PoE and the onboard Wi-Fi. I presume if you power the Pi 3 via a standard micro usb power supply that you can connect with Wi-Fi sucessfully? Try that first and then power via the PoE method and see if still connects okay. I just tried a Pi3 with our PoE ...
by RGJ-PI
Fri Dec 20, 2019 12:38 pm
Forum: Troubleshooting
Topic: Setting up faux pas
Replies: 2
Views: 152

Re: Setting up faux pas

To sort the overscan issue see WHH's reply. If you need to overide the actual screen pixel resolution then you can still do this but not from Raspberry Pi Configuration tool. Instead in the preferences menu there is an app called Screen Configuration. Run that and it will show screens connected. Go ...
by RGJ-PI
Fri Dec 20, 2019 12:27 pm
Forum: Troubleshooting
Topic: Changing the Digital Clock Font Color in Rasbian
Replies: 1
Views: 82

Re: Changing the Digital Clock Font Color in Rasbian

In the main start menu go to Preferences and select Appearance Settings.
Select the Taskbar tab and click on Text Colour there. That will change the clock (and other menu bar fonts) to the colour of your choice.
by RGJ-PI
Thu Dec 19, 2019 4:33 pm
Forum: Troubleshooting
Topic: Struggling with the terminal
Replies: 5
Views: 181

Re: Struggling with the terminal

The curl command you copied on here appears to work fine. If you click on the https: part of the command does your browser open a text page starting..

#!/usr/bin/env bash
# PiVPN: Trivial OpenVPN setup and configuration
by RGJ-PI
Thu Dec 19, 2019 2:33 pm
Forum: Troubleshooting
Topic: Hardware Problem with HDMI port
Replies: 10
Views: 357

Re: Hardware Problem with HDMI port

Your power rails look good but there is a difference where you are measuring 3.25V. This should be pulled to ground by the MOSFET when the monitor is plugged in. Specifically by HDMI pin 19 being at 5V (hotplug detect).
by RGJ-PI
Thu Dec 05, 2019 3:08 pm
Forum: HATs and other add-ons
Topic: PoE hat, Raspberry Pi 4, not able to power off
Replies: 64
Views: 12046

Re: PoE hat, Raspberry Pi 4, not able to power off

We have received the Unifi PoE switch and checked it with Pi 3+ and Pi 4 4GB. Up to date Buster. I've not been able to reproduce your reboot issue so far. No reboot after shutdown via desktop or terminal command. Tried with current version PoE Hat and earlier version. Can you confirm the PoE switch ...
by RGJ-PI
Tue Dec 03, 2019 10:12 am
Forum: HATs and other add-ons
Topic: PoE hat, Raspberry Pi 4, not able to power off
Replies: 64
Views: 12046

Re: PoE hat, Raspberry Pi 4, not able to power off

Thanks for the info onedr0p

We have ordered in the make of PoE switch you are using to investigate your problem here in Cambridge. We will reply with findings once we receive it and have run some investigations.
by RGJ-PI
Fri Nov 22, 2019 5:13 pm
Forum: Troubleshooting
Topic: Please help me! Broken component
Replies: 2
Views: 168

Re: Please help me! Broken component

As rpdom said, the boards really aren't user serviceable but if you have suitable fine pitch soldering equipment you can give it a try. Could you post a picture clearly showing the damaged component and I'll let you know what the part is.
by RGJ-PI
Mon Nov 18, 2019 2:03 pm
Forum: Troubleshooting
Topic: R12 value on a Raspberry Pi 3B?
Replies: 9
Views: 355

Re: R12 value on a Raspberry Pi 3B?

R12 is a 15R 0402 resistor.
by RGJ-PI
Thu Nov 14, 2019 2:55 pm
Forum: Advanced users
Topic: power up rpi4 from embedded system 3.3Vdc supply
Replies: 2
Views: 170

Re: power up rpi4 from embedded system 3.3Vdc supply

Absolutely not. The 5V input goes to the main regulator input and then generates various system Voltages including the 3V3 rail you mention. Feeding 3V3 into the regulator output certainly won't power the other rails and will probably damage the regulator as well.
by RGJ-PI
Thu Nov 07, 2019 10:16 am
Forum: Troubleshooting
Topic: [Pi Zero W] Identify SMD component
Replies: 9
Views: 1058

Re: [Pi Zero W] Identify SMD component

The part is a 100n 0402 sized ceramic capacitor.
by RGJ-PI
Tue Oct 01, 2019 12:31 pm
Forum: Troubleshooting
Topic: Smd component fails
Replies: 2
Views: 192

Re: Smd component fails

That part is a 100nF capacitor used to decouple the memory. Provided it is cleanly removed and there are no pad shorts with old solder etc then the board will almost certainly work fine with it missing as it is one of six 100nF caps for this chip.
by RGJ-PI
Tue Aug 27, 2019 1:23 pm
Forum: Troubleshooting
Topic: Raspberry pi 3B
Replies: 2
Views: 130

Re: Raspberry pi 3B

I'm guessing you previously asked this on StackOverflow but if not..

The github clone link on that IOTA doc step 2 is incorrect. Try

Code: Select all

git clone https://github.com/caddyserver/caddy.git 
instead and continue with step 3 onwards.
by RGJ-PI
Mon Aug 19, 2019 11:17 am
Forum: Beginners
Topic: Charging Indicator
Replies: 4
Views: 1005

Re: Charging Indicator

If you are just interested in measuring charge current then Texas Instruments make a very easy to use current sense chip that you can read directly on a Pi with simple Python script.
http://www.ti.com/product/INA260#
by RGJ-PI
Fri Aug 16, 2019 9:50 am
Forum: Troubleshooting
Topic: Missing Green LED
Replies: 1
Views: 134

Re: Missing Green LED

When you say missing, do you mean it was missing from new or it has been mechanically damaged since you've owned it? If the former could you take a close up picture of the missing led area and also the SN barcode on the underside near the micro sd card socket so we can check the build record.

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