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by pcmanbob
Thu Aug 16, 2018 7:10 pm
Forum: Automation, sensing and robotics
Topic: switch on/off 12V 7A
Replies: 2
Views: 63

Re: switch on/off 12V 7A

Hi.

Yes you can use a ready made relay board but probably not that one as it requires 12v to operate it and the pi gpio is only 3.3v.

Look for a relay board that says it's compatible with the pi 3.3v gpio.
by pcmanbob
Thu Aug 16, 2018 2:10 pm
Forum: Troubleshooting
Topic: only GPIO.PUD_UP works but event happens both rising and falling
Replies: 6
Views: 81

Re: only GPIO.PUD_UP works but event happens both rising and falling

The 1k resistor in series with the switch is just there as protection should you set you gpio pin as an output while its connected to ground or 3.3v which could result in high current flow which would damage your pi. explained here : https://github.com/raspberrypilearning/physical-computing-guide/bl...
by pcmanbob
Thu Aug 16, 2018 1:15 pm
Forum: Troubleshooting
Topic: only GPIO.PUD_UP works but event happens both rising and falling
Replies: 6
Views: 81

Re: only GPIO.PUD_UP works but event happens both rising and falling

The first question is how is your switch wired as this will change how your code works. For the first code example the switch needs to be wired gpio pin - 1K resistor - switch - gpio ground. so when the button is pressed the gpio pin is pulled to ground then upon switch release the rising input will...
by pcmanbob
Thu Aug 16, 2018 11:58 am
Forum: Networking and servers
Topic: send ip on boot
Replies: 1
Views: 32

Re: send ip on boot

Without seeing your actual code we cant tell if you have an error in it, just because the web site has the code listed does not mean your code is exactly the same. If you have SSMTP and mail utils installed on your pi then you could try this code which is just a bash script , which i saved as ipemai...
by pcmanbob
Thu Aug 16, 2018 11:31 am
Forum: Troubleshooting
Topic: Ethernet port has no lights turned on
Replies: 12
Views: 206

Re: Ethernet port has no lights turned on

So from my own testing. Using a LAN cable that has cores 7 & 8 which are faulty and cores 1 to 6 which are working fine, using a pi3B+ Plugging cable in to a 10/100mb switch pi connects ok but at 100mb, plugging same pi and cable in to 10/100/1000mnb switch pi does not connect, even if you boot the ...
by pcmanbob
Wed Aug 15, 2018 8:06 am
Forum: General discussion
Topic: Raspberry pi code on boot up
Replies: 4
Views: 161

Re: Raspberry pi code on boot up

I don't think that is going to work if the pi has hung, If the pi has hung for some reason and you can't use the normal method of exiting and rebooting then you switches wont work either because your program monitoring them will also probably be hung. As I don't use kodi I can off any help or advice...
by pcmanbob
Tue Aug 14, 2018 7:11 pm
Forum: Troubleshooting
Topic: Ethernet port has no lights turned on
Replies: 12
Views: 206

Re: Ethernet port has no lights turned on

A 1000 byte network requires all 8 cores of the LAN cable to be connected, its possible that the cables you tried were just 4 core cables or have a faulty core within them. Desktop PCs and laptops will often work even with these cables because they will automatically switch to 10/100 byte networking...
by pcmanbob
Mon Aug 13, 2018 6:26 pm
Forum: Troubleshooting
Topic: GPIO Pins are always on for some reason
Replies: 5
Views: 111

Re: GPIO Pins are always on for some reason

From the little information you have provided no one can help you because we have no idea how your circuit is connected to you pi.

You need to provide a diagram of your circuit showing how it's connected to your pi or post some pictures showing the circuit and connections to pi.
by pcmanbob
Mon Aug 13, 2018 12:24 pm
Forum: General discussion
Topic: Raspberry pi code on boot up
Replies: 4
Views: 161

Re: Raspberry pi code on boot up

Hi. So the first thing is please use code tags when posting code to preserve the indentation as python relies on indentation to work. Add [ code] at the top code goes here and [/code] at the bottom. your code will then look like this #!/bin/python import RPi.GPIO as GPIO import time import os # Use ...
by pcmanbob
Mon Aug 13, 2018 11:57 am
Forum: Python
Topic: Cron job not running
Replies: 2
Views: 73

Re: Cron job not running

Hi. Not sure why you are trying to set up a cron job using python ? The way I and probably most people would do it would be to run crontab -e at the command line or in a terminal window then add you cron line to the end of the file making sure you have a blank line after it. example of how to do it ...
by pcmanbob
Mon Aug 13, 2018 8:33 am
Forum: Raspbian
Topic: Raspbian UI is all wrong
Replies: 4
Views: 235

Re: Raspbian UI is all wrong

Well I can't see any thing in your posted information that would cause the problems you are having , may be you SD card has some corruption due to a bad power off or the card is starting to fail. if you have a spare SD card write a copy of your SD card backup to it and see if that works correctly, y...
by pcmanbob
Mon Aug 13, 2018 8:29 am
Forum: Troubleshooting
Topic: Kingston SDHC Woes
Replies: 6
Views: 507

Re: Kingston SDHC Woes

Hi.

Is it possible that these are fake SD cards ?

try formatting the card as fat then try putting 16Gb of data on them like pictures for example or use one of the SD card tester programs to test them, can advise of one suitable for Linux only use one for windows.
by pcmanbob
Mon Aug 13, 2018 8:25 am
Forum: Raspbian
Topic: No Bluetooth adapter found.
Replies: 7
Views: 166

Re: No Bluetooth adapter found.

Ok so there are a couple of checks left to do . look in config.txt for this line : dtoverlay=pi3-disable-bt and remove it if found. and look in : /etc/modprobe.d/raspi-blacklist.conf and look for #bt blacklist btbcm blacklist hci_uart if found comment them out with a # at the start of each of the li...
by pcmanbob
Sun Aug 12, 2018 12:43 pm
Forum: General discussion
Topic: Where is my SD Card?
Replies: 4
Views: 222

Re: The hell is my SD Card?

If you are putting an SD card in to your Mac that has raspbian on it then what you are seeing is what I would expect. There are two partitions on the SD card a fat one which is visable on your mac a Linux one which is not. The fat one is the smaller of the two 40 to 70mb is probably about right the ...
by pcmanbob
Sun Aug 12, 2018 8:52 am
Forum: Beginners
Topic: i am unable to set up my raspberry pi
Replies: 2
Views: 91

Re: i am unable to set up my raspberry pi

Hi. Assuming you have a pi3B+ you might find your 3.1A power supply if that's what it is and not a battery charger, may not actually be able to supply 3.1A at 5V. does the red LED flicker or go out ? You might be better off writing raspbian directly to your SD card using etcher. Download from here :...
by pcmanbob
Sun Aug 12, 2018 8:40 am
Forum: Raspbian
Topic: Raspbian UI is all wrong
Replies: 4
Views: 235

Re: Raspbian UI is all wrong

Hi. So is this a new install of raspbian or one you have been using for some time ? Have you made any changes to the config.txt file or using the GUI to make changes to the interface ? Have you installed any software that may have made changes to the GUI ? The more information you can provide the be...
by pcmanbob
Sat Aug 11, 2018 1:55 pm
Forum: Raspbian
Topic: No Bluetooth adapter found.
Replies: 7
Views: 166

Re: No Bluetooth adapter found.

You could try rfkill list this will list Wi-Fi and Bluetooth status this is from my pi3B+ will both enabled and working as far as I know. [email protected]:~ $ rfkill list 0: phy0: Wireless LAN Soft blocked: no Hard blocked: no 1: hci0: Bluetooth Soft blocked: no Hard blocked: no
by pcmanbob
Sat Aug 11, 2018 1:43 pm
Forum: Automation, sensing and robotics
Topic: Pi-controlled relays
Replies: 5
Views: 155

Re: Pi-controlled relays

I think you will find that relays are designed to be powered for long periods of time, as long as the coil is powered with the correct voltage which it should be in a commercially designed product you should have no problems . Relays are still used extensively in industrial equipment in control syst...
by pcmanbob
Sat Aug 11, 2018 10:31 am
Forum: General discussion
Topic: LCD display returning 5V
Replies: 32
Views: 634

Re: LCD display returning 5V

You might be able to prove if its the display if you just connect the minimum to it . 5v and ground to power it, ground for the back light and 470Ω resistor feeding 5v to the back light and 10 K power wired between 5v and ground with centre pin feeding the contrast. you should then be able to get a ...
by pcmanbob
Fri Aug 10, 2018 11:38 am
Forum: Python
Topic: Trying to make a countdown timer to trigger a camera, seeing odd behavior.
Replies: 1
Views: 56

Re: Trying to make a countdown timer to trigger a camera, seeing odd behavior.

Hi. I suspect the reason your print out is changing to scientific notation is because the number is to long to be printed on the screen, this may also have some thing to do with the second problem you are having. So I changed your code a bit to limit the number of figures after the decimal point to ...
by pcmanbob
Thu Aug 09, 2018 3:00 pm
Forum: General discussion
Topic: LCD display returning 5V
Replies: 32
Views: 634

Re: LCD display returning 5V

So doing some tests on my own 20x4 LCD with just the LCD powered with 5v and Ground connection then the data pins show values of between 0 and 5v . once the pi is connected and driving the display with RW connected to ground the data pins now have values of between 0 and 3.3v were they are connected...
by pcmanbob
Thu Aug 09, 2018 9:19 am
Forum: Python
Topic: LCD Doesn't Display Text
Replies: 13
Views: 191

Re: LCD Doesn't Display Text

If you cant see the blocks on your display then it must be a wiring fault or a bad display, as you can see from my picture you don't need to actually have the display connected to the pi to get the blocks to show. Then I think your next step is to post some pictures of yoru set-up so we can check yo...
by pcmanbob
Wed Aug 08, 2018 6:43 pm
Forum: Troubleshooting
Topic: Raspberry Pi Clonezilla Image Failure
Replies: 4
Views: 60

Re: Raspberry Pi Clonezilla Image Failure

I've used clonezilla on several occasions on HD's containing both windows and linux operating systems with great success even once on an HD that was failing, I was able to copy 99% of the drive. I have always used it to copy from on HD to another HD just mirroring the source to the destination drive...
by pcmanbob
Wed Aug 08, 2018 6:32 pm
Forum: Troubleshooting
Topic: Raspberry PI 3 "No Signal" , No green light
Replies: 2
Views: 57

Re: Raspberry PI 3 "No Signal" , No green light

Is your Pi not booting? (The Boot Problems Sticky)

viewtopic.php?f=28&t=58151
by pcmanbob
Wed Aug 08, 2018 6:18 pm
Forum: Python
Topic: LCD Doesn't Display Text
Replies: 13
Views: 191

Re: LCD Doesn't Display Text

So checking the link you posted shows the LCD you have uses an HD44780 equivalent LCD controller so RPLCD should be able to drive it without any problems. You should be able to get the display to show blocks like this https://i.imgur.com/RjwB8aA.jpg this is a 20x4 LCD but your 16x4 should still disp...

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