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by pcmanbob
Sun Oct 17, 2021 7:20 pm
Forum: General discussion
Topic: Dupont cables connection problem
Replies: 10
Views: 226

Re: Dupont cables connection problem

I still use dupont cables for experimentation , but I remove the plastic form the cables and close up the metal socket inside to make them a better fit then replace the plastic cover. For permanent / finished projects I tend to solder wires to PCB's but I still tend to use sockets on the pi end just...
by pcmanbob
Sun Oct 17, 2021 7:08 pm
Forum: Automation, sensing and robotics
Topic: Automated email send out on event not working
Replies: 25
Views: 949

Re: Automated email send out on event not working

Then you are going to have to re-write your code. Something like this. cron calls python code , python code turns on sensor then waits 5min, then checks status of sensor, reads last sensor state from file on SD card If its changed then send mail, you will need to add a check to see if its gone from ...
by pcmanbob
Sun Oct 17, 2021 3:02 pm
Forum: Automation, sensing and robotics
Topic: Interfacing with inline fan.
Replies: 7
Views: 310

Re: Interfacing with inline fan.

So the zener diode is just there to limit the the voltage that an be applied to the PWM input/blue wire, not sure why the manufacture would include it seeing as the red wire is a 10V output, But I guess you could be using a separate supply to power the PWM or may be the Red wire /10V is a nominal vo...
by pcmanbob
Sun Oct 17, 2021 11:41 am
Forum: Troubleshooting
Topic: Getting error while trying to update buster
Replies: 1
Views: 53

Re: Getting error while trying to update buster

Hi. A failure message like that normally indicates a problem with your DNS. Can you access any web sites from your pi ? what results do these 8 commands produce when run from a command line or terminal window ? ifconfig ip addr show ip route ip -4 route | awk '/default/ {print $3}' ping -c3 $(ip rou...
by pcmanbob
Sun Oct 17, 2021 11:33 am
Forum: Troubleshooting
Topic: Sudden death on Pi 3B+
Replies: 3
Views: 136

Re: Sudden death on Pi 3B+

Hi.

The pi3B+ was known for sudden failures of the pmic which results in the loss of the 3.3V

Your pi is not repairable :( :( :(
by pcmanbob
Sun Oct 17, 2021 11:28 am
Forum: General discussion
Topic: fixing a dead RPI 4
Replies: 2
Views: 194

Re: fixing a dead RPI 4

I would say you pi is dead and beyond repair , you/we have no way of knowing what other damage your have done.

Also the PMIC although a standard part number , is specifically program for the pi and is not available to the general public.
by pcmanbob
Sun Oct 17, 2021 11:23 am
Forum: Beginners
Topic: Pi hole, Raspbian desktop + 3.5" touchscreen question
Replies: 1
Views: 85

Re: Pi hole, Raspbian desktop + 3.5" touchscreen question

Seeing as you are asking about the workings of pi-hole you'd be better asking on the pi-hole support page

https://discourse.pi-hole.net/

After all they should be the experts on there software set-up, so if what you want is possible they should know.
by pcmanbob
Fri Oct 15, 2021 8:13 am
Forum: Troubleshooting
Topic: GPIO stuck on/off issue
Replies: 7
Views: 242

Re: GPIO stuck on/off issue

Hi. First thing to check is that you have the ribbon cable connected the correct way round, is easy to reverse the connection at the pi end. I would suggest you check to see if you have 5V and 3.3V and grounds on the correct pins at the breadboard end, do this using a multi meter. You could also tes...
by pcmanbob
Thu Oct 14, 2021 6:56 pm
Forum: Automation, sensing and robotics
Topic: Interfacing with inline fan.
Replies: 7
Views: 310

Re: Interfacing with inline fan.

Any general purpose NPN transistor should be fine, but you may need to change the base resistor. Your diode will not do you need a zener diode with the part no. I suggested. You need to build the circuit shown to use pwm speed control , if you just want on off then a relay switching a connection bet...
by pcmanbob
Thu Oct 14, 2021 3:01 pm
Forum: Other projects
Topic: Work project
Replies: 5
Views: 260

Re: Work project

Hi. So yes you will need additional I/O boards, One for the relays , probably one to read the pressure from a 4-20mA transducer, Depending on what you want to drive from the output for pressure alarms you may well need some interfacing circuits. Yes it should be possible using a pi, I would suggest ...
by pcmanbob
Wed Oct 13, 2021 10:34 pm
Forum: Automation, sensing and robotics
Topic: Interfacing with inline fan.
Replies: 7
Views: 310

Re: Interfacing with inline fan.

I assume the fan needs 10V to power it , but the information supplied does not mention that specifically only implies it from the wiring connected to the plug as shown. So the PWM will also need to be 10V based so you need to use the bottom left driver circuit of the 4 shown, as my first post sugges...
by pcmanbob
Wed Oct 13, 2021 7:12 pm
Forum: Automation, sensing and robotics
Topic: Interfacing with inline fan.
Replies: 7
Views: 310

Re: Interfacing with inline fan.

As your fan appears to have a speed controller already built in all you need to do is build the speed control via pwm circuit shown bottom left of the 4 circuits and drive the base of the transistor from one of the pi / Pico gpio pins.

If you need component values suggesting then please ask.
by pcmanbob
Wed Oct 13, 2021 2:02 pm
Forum: General discussion
Topic: Servo not working with Raspberry Pi but works with Arduino
Replies: 10
Views: 483

Re: Servo not working with Raspberry Pi but works with Arduino

Pointless arguing amongst our selves , as the OP has never come back to say if the posted test code worked or not,

or if they had the servo connected correctly or not.

I personally have never had a problem driving generic sg90 servos from the pi, right from when the original pi was released.
by pcmanbob
Tue Oct 12, 2021 1:45 pm
Forum: Troubleshooting
Topic: Under-voltage but the power supply is good.
Replies: 8
Views: 290

Re: Under-voltage but the power supply is good.

The usual reasons for a low volt warning is either

power supply that can't supply the required current at 5 - 5.1V

or

the cable between the power supply and the pi has a wire gauge the is to small and is causing a volt drop over the cable length.
by pcmanbob
Mon Oct 11, 2021 8:50 am
Forum: Automation, sensing and robotics
Topic: Automated email send out on event not working
Replies: 25
Views: 949

Re: Automated email send out on event not working

So changing the time sleep at the bottom of the program will make no difference , all it does is keep the program running , you can set any time you like and it will not change how the program runs, because you are using event detect to trigger the sending of mail. So as soon as an even is detected ...
by pcmanbob
Sun Oct 10, 2021 8:26 am
Forum: Automation, sensing and robotics
Topic: Automated email send out on event not working
Replies: 25
Views: 949

Re: Automated email send out on event not working

So I ran the code I posted above I used a simple wire loop switching gpio between high and low and apart from the very first trigger were I got both emails, it worked correctly from then on , I only ever got one email either wet or dry. The only way I got get lots of emails was to constantly disconn...
by pcmanbob
Sat Oct 09, 2021 7:20 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 SD card corruption after reboot
Replies: 7
Views: 251

Re: Raspberry Pi 4 SD card corruption after reboot

B.Goode wrote:
Sat Oct 09, 2021 3:42 pm
pcmanbob wrote:
Sat Oct 09, 2021 2:50 pm
Buying from amazon is guarantee that you have a genuine card.

Even with Midlands understatement or irony, I find it difficult to believe you meant to say that...
:lol: :lol: No it should have been isn't guarantee that you have a genuine card.
by pcmanbob
Sat Oct 09, 2021 7:14 pm
Forum: Automation, sensing and robotics
Topic: Automated email send out on event not working
Replies: 25
Views: 949

Re: Automated email send out on event not working

It sounds like the part of the program that detects it's dry is being trigger then being triggered again. Over what sort of time period do you get the emails. When I get a spare 5 min and my bench is clear I will try and set up a pi to test the program. edit.. Looking at the code again , you don't h...
by pcmanbob
Sat Oct 09, 2021 2:50 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4 SD card corruption after reboot
Replies: 7
Views: 251

Re: Raspberry Pi 4 SD card corruption after reboot

Buying from amazon is guarantee that you have a genuine card.

Then try F3 that's available for mac , Linux and windows

https://fight-flash-fraud.readthedocs.io/en/stable/
by pcmanbob
Sat Oct 09, 2021 11:47 am
Forum: Troubleshooting
Topic: Raspberry Pi 4 SD card corruption after reboot
Replies: 7
Views: 251

Re: Raspberry Pi 4 SD card corruption after reboot

HI. so were did you get your SD cards from ? Have you tried testing then using h2testw to see if they are fake or faulty ? https://www.softpedia.com/get/System/System-Miscellaneous/H2testw.shtml Once you know they are good then try flashing one of them with RPI OS and see if that will work correctly...
by pcmanbob
Sat Oct 09, 2021 11:42 am
Forum: Beginners
Topic: Making the RPi control a dc motor and heating element
Replies: 24
Views: 898

Re: Making the RPi control a dc motor and heating element

So here are examples of circuits to drive a 5V relay directly or to drive 5V relay board using an external 5V supply and opto isolator to isolate the pi from any electrical interference . https://i.imgur.com/ORxRb1S.jpg https://i.imgur.com/gObNyhc.jpg You may have to change resistor value depending ...
by pcmanbob
Fri Oct 08, 2021 8:59 am
Forum: Advanced users
Topic: RUN pin start control
Replies: 7
Views: 229

Re: RUN pin start control

I know the gpio on the pi is not 5V tolerant and applying 5V will damage your pi , I suspect the run pin is the same.
by pcmanbob
Fri Oct 08, 2021 8:53 am
Forum: Beginners
Topic: Making the RPi control a dc motor and heating element
Replies: 24
Views: 898

Re: Making the RPi control a dc motor and heating element

I know you said you left things out of the drawings, what else would there be? It depends on how you intend to do this are you going to build the entire circuit from scratch on your own pcb/prototype board or do you just want to add an opto isolator to an existing relay board ? Might also help if y...
by pcmanbob
Thu Oct 07, 2021 3:05 pm
Forum: General discussion
Topic: Raspberry Pi 3 B+ - python threading Timer call inconsistent on boot up
Replies: 4
Views: 158

Re: Raspberry Pi 3 B+ - python threading Timer call inconsistent on boot up

So the pi does not have a real time clock on board and only sets the correct time once it has a network connection , so the time at boot will be out by at least 15 min because I think the current time is saved every 15 min for use at start up. But if you are just pulling the power and not shutting d...
by pcmanbob
Thu Oct 07, 2021 2:53 pm
Forum: Troubleshooting
Topic: ethernet (eth0) not working
Replies: 5
Views: 168

Re: ethernet (eth0) not working

Hi. So if this is a new install of the OS on the pi the first this I would suggest is re-flashing the SD card if not then flash a fresh copy of RPI OS on to a spare SD card. Then try booting your pi with it connected to your router using a network cable which has all 8 cores connected. if you still ...

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