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by pcmanbob
Thu Feb 27, 2020 1:48 pm
Forum: HATs and other add-ons
Topic: Using a 5v relay with Raspberry PI... Plus some electrical safety concerns
Replies: 1
Views: 51

Re: Using a 5v relay with Raspberry PI... Plus some electrical safety concerns

Hi. So first lets address the safety issue, If you don't have any electrical qualifications please don't start making changes to your coffee maker or you might just end up killing yourself or someone else or even sitting fire to were ever your coffee make is located. So if you really want to do this...
by pcmanbob
Thu Feb 27, 2020 11:40 am
Forum: Troubleshooting
Topic: Wifi stopped working on my raspberry pi
Replies: 6
Views: 121

Re: Wifi stopped working on my raspberry pi

I suggest you start by downloading the latest raspbian image and flash that to a spare SD card then add you wpa-supplicant file to the SD card and a file called ssh or ssh.txt and try booting your pi from that. If it had just been a failure of the wifi on your pi then adding a wifi dongle , assuming...
by pcmanbob
Wed Feb 26, 2020 1:42 pm
Forum: Troubleshooting
Topic: [Solved] RPi3 headless server to RPi4: no boot
Replies: 4
Views: 97

Re: RPi3 headless server to RPi4: no boot

Try putting the SD card back in the pi3 and run

Code: Select all

sudo apt update
sudo apt full-upgrade
then ry it in your pi4
by pcmanbob
Wed Feb 26, 2020 1:39 pm
Forum: General discussion
Topic: Pi 3 A+ setup
Replies: 3
Views: 94

Re: Pi 3 A+ setup

Hi. If you really want to use noobs then look at this for how to install it. https://projects.raspberrypi.org/en/projects/raspberry-pi-setting-up/2 but if you are only going to install raspbian you might be better just flashing the SD card directly with a raspbian image file using etcher https://www...
by pcmanbob
Wed Feb 26, 2020 11:55 am
Forum: Troubleshooting
Topic: GPIO.wait_for_edge
Replies: 7
Views: 102

Re: GPIO.wait_for_edge

one way to look at problems like this is to add a lot of print statements for the variable in question so you can see how its changing as the code progresses like this print ("before wait", GPIO.input(vlez)) GPIO.wait_for_edge(vlez, GPIO.RISING) print ("after wait", GPIO.input(vlez)) # if we're here...
by pcmanbob
Wed Feb 26, 2020 11:15 am
Forum: General discussion
Topic: Can a 12v relay be run using inputs from a different sensor.
Replies: 6
Views: 167

Re: Can a 12v relay be run using inputs from a different sensor.

You should be aware you can't drive relays directly from the gpio pins if they do not have there own driver circuit on the pcb, So if you are going to purchase just the relay like this https://i.imgur.com/XtpF3xY.jpg then you really need to purchase the 5v version and then build your own driver circ...
by pcmanbob
Wed Feb 26, 2020 11:08 am
Forum: Other programming languages
Topic: Linux shell script to control pi motor hat
Replies: 2
Views: 41

Re: Linux shell script to control pi motor hat

Hi.

I guess that would depend on the motor hat in question and how its controlled if you use python.

You need to give more details about the hat and how its controlled in python then someone may be able to help.
by pcmanbob
Wed Feb 26, 2020 11:05 am
Forum: Troubleshooting
Topic: No Input Display
Replies: 1
Views: 29

Re: No Input Display

Hi. From the little information supplied all I can say for sure is that is you SD card has gone write protect then it must have a problem that has cause the SD cards internal controller to make it write protected to protect the data on the card. This could be because its an old SD card you have reus...
by pcmanbob
Wed Feb 26, 2020 10:55 am
Forum: Other
Topic: Raspberry Pi 3B can't connect to my router and internet [KALI]
Replies: 1
Views: 31

Re: Raspberry Pi 3B can't connect to my router and internet [KALI]

Hi. So first off Kali Linux has its own support forum here : https://www.kali.org/community/ It is not supported on this forum. If you want help here then you need to install Raspbian on your SD card and boot your pi with that with no changes/set-up necessary you pi should connect to your router wit...
by pcmanbob
Wed Feb 26, 2020 10:48 am
Forum: Troubleshooting
Topic: Relay turns on when RPi boots
Replies: 2
Views: 65

Re: Relay turns on when RPi boots

Your relay problem is probably because you are using a 5v relay board that is active low , see here for explanation https://www.raspberrypi.org/forums/viewtopic.php?f=91&t=83372&p=1225448#p1225448 you should also be aware that you are using the 3.3v gpio as a ground for a 5v circuit not god for the ...
by pcmanbob
Tue Feb 25, 2020 6:59 pm
Forum: Beginners
Topic: Need to find command for crontab on reboot
Replies: 9
Views: 240

Re: Need to find command for crontab on reboot

You did not follow my instructions and change you Cron entry, you are missing
>> /home/pi/errlog.txt 2>&1 from the end of the Cron line.

Try

Code: Select all

@reboot sleep 10 && /storage/script/Onreboot.sh >> /storage/script/errlog.txt 2>&1
*/1 * * * *  bash ./script/ventilo.sh
by pcmanbob
Tue Feb 25, 2020 2:40 pm
Forum: General discussion
Topic: Can a 12v relay be run using inputs from a different sensor.
Replies: 6
Views: 167

Re: Can a 12v relay be run using inputs from a different sensor.

So the relay you linked requires 12V to power it so you would required a separate 12V power supply, you may also find you cant drive it on/off directly from the pi gpio which is only 3.3v so you may need an interface circuit between the gpio pin and the IN terminal on the relay. the DHT22 sensor is ...
by pcmanbob
Tue Feb 25, 2020 2:28 pm
Forum: Troubleshooting
Topic: Wifi stopped working on my raspberry pi
Replies: 6
Views: 121

Re: Wifi stopped working on my raspberry pi

You need to give use some thing to work with

which pi
which OS are you using

and please post the results of these commands

Code: Select all

ifconfig
ping -c3 8.8.8.8
ping -c3 google.com
cat /etc/resolv.conf
by pcmanbob
Tue Feb 25, 2020 2:22 pm
Forum: Troubleshooting
Topic: GPIO.wait_for_edge
Replies: 7
Views: 102

Re: GPIO.wait_for_edge

That's because wait for edge does what it says on the tin, it waits for the edge before continuing. ref doc https://sourceforge.net/p/raspberry-gpio-python/wiki/Inputs/ So in your code the line GPIO.wait_for_edge(vlez, GPIO.RISING) will wait for the rising edge before allowing the code to continue e...
by pcmanbob
Tue Feb 25, 2020 9:23 am
Forum: Raspbian
Topic: Download of rasbian failing
Replies: 1
Views: 78

Re: Download of rasbian failing

Just download Raspbian lite in under 60 sec
and Raspbian with desktop and recommended software in about 3 min

which is actually faster than it has been downloading recently.
by pcmanbob
Tue Feb 25, 2020 9:15 am
Forum: Beginners
Topic: Need to find command for crontab on reboot
Replies: 9
Views: 240

Re: Need to find command for crontab on reboot

If it wont work with cron it likely wont work with any other method, so you need to find out whats happening when you call your script. first modify your scrip like this echo " Start " modprobe -r dvb_usb_af9035 modprobe dvb_usb_af9035 echo " Finish " then change your cron line so it looks like this...
by pcmanbob
Mon Feb 24, 2020 9:29 pm
Forum: Networking and servers
Topic: static IP on the router - Citadel email server
Replies: 1
Views: 57

Re: static IP on the router - Citadel email server

You look to be on the wrong page on your router control panel. You are attempting to set a static IP for you incoming broadband service, you can't do this only your service provider can set a static IP as it's their network . If you want a static IP for you broadband service you normally have to pay...
by pcmanbob
Mon Feb 24, 2020 12:30 pm
Forum: Raspbian
Topic: Raspbian 10 - 1 Wire Error
Replies: 6
Views: 162

Re: Raspbian 10 - 1 Wire Error

I still think its a hardware problem , because its been working for 3 months without problems , so unless you have changed some thing in your software you are still using the same software as you were for the 3 working months , so why would it fail now. The in built 1-wire interface is very reliable...
by pcmanbob
Mon Feb 24, 2020 10:34 am
Forum: Troubleshooting
Topic: Connecting multiple sensors to the Pi
Replies: 2
Views: 77

Re: Connecting multiple sensors to the Pi

Hi. Both the devices you want to connect to your pi are likely to need resistors connected to them and the pi as well, so connecting them directly to the gpio may not be so simple, for experimentation you can use a breadboard , once you project is working and finalised then you can move to prototypi...
by pcmanbob
Mon Feb 24, 2020 10:22 am
Forum: Raspbian
Topic: Raspbian 10 - 1 Wire Error
Replies: 6
Views: 162

Re: Raspbian 10 - 1 Wire Error

If you use a 5v and ground to power your DS18B20 and then use a 3.3v pull up with a 4.7K resistor there is no need for a level shifter as the data pin will never riser higher than 3.3v so your gpio is safe. Then I would suspect your DS18B20 sensors there are a lot of cheap ones for sale on line that...
by pcmanbob
Mon Feb 24, 2020 10:12 am
Forum: HATs and other add-ons
Topic: Enable hot-plugging into breadboard by hardware
Replies: 13
Views: 292

Re: Enable hot-plugging into breadboard by hardware

You cant use software to protect your pi against physical misconnection.

The pi does not take long to boot / shutdown even my pi4 running the full desktop version of raspbian takes less than 60 seconds to boot
by pcmanbob
Mon Feb 24, 2020 8:56 am
Forum: Beginners
Topic: Non Contact Voltage Detector Mashup
Replies: 11
Views: 315

Re: Non Contact Voltage Detector Mashup

I very much doubt that circuit will work at 3.3v , you might get it to work at 5v,

then you could use an opto isolator in place of the LED to interface it to the pi gpio to monitor the input.
by pcmanbob
Mon Feb 24, 2020 8:49 am
Forum: Raspbian
Topic: Raspbian 10 - 1 Wire Error
Replies: 6
Views: 162

Re: Raspbian 10 - 1 Wire Error

I have seen this sort of behaviour of 1-wire devices myself, your problem may be due to the sensors themselves going faulty or a problem with your wiring , especially if you did not use soldered connections. It might also be a problem with interference , but this is less likely if your setup has bee...
by pcmanbob
Sun Feb 23, 2020 5:57 pm
Forum: Beginners
Topic: Need to find command for crontab on reboot
Replies: 9
Views: 240

Re: Need to find command for crontab on reboot

Using the first Cron line you posted , 2 points

1. Did you make your Onreboot.sh file executable ?

2. Try changing ./ To the full directory path , were your Onreboot.sh is saved.

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