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by pcmanbob
Sun Nov 17, 2019 11:11 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 308

Re: 8ch relay 12V

yes the com is only there to provide a connection for the protection diodes to the supply voltage that the ULN2803A is switching the ground to, when switching inductive loads like motors, as you are only switching a couple of LED's you don't need it. I suggest you read the data sheet http://www.ti.c...
by pcmanbob
Sun Nov 17, 2019 10:57 am
Forum: Android
Topic: Help with Emteria and 3B
Replies: 1
Views: 111

Re: Help with Emteria and 3B

As android is generally not supported here, and Emteria OS appears to be a commercial product I suggest you as for help from the supplier/creator of this particular version of android.

https://forum.emteria.com/
by pcmanbob
Sun Nov 17, 2019 10:52 am
Forum: Python
Topic: Push button to make picture
Replies: 2
Views: 98

Re: Push button to make picture

please don't double post.

I have answered in you original thread. https://www.raspberrypi.org/forums/view ... 2&t=256959
by pcmanbob
Sun Nov 17, 2019 10:49 am
Forum: Python
Topic: Push button to make picture
Replies: 12
Views: 217

Re: Push button to make picture

So assuming your switch is connected like this https://i.imgur.com/z8wYFrm.jpg try running this code #!/usr/bin/env python import sys, os, time import RPi.GPIO as GPIO GPIO.setmode(GPIO.BOARD) GPIO.setup(11, GPIO.IN) # push button (pin 11) while True: while GPIO.input(11) == 1: #loops waiting for bu...
by pcmanbob
Sun Nov 17, 2019 10:27 am
Forum: Troubleshooting
Topic: Cannot setup SSMTP properly to send mail via SMTP Gmail
Replies: 56
Views: 804

Re: Cannot setup SSMTP properly to send mail via SMTP Gmail

OK to send an attachment when using MSMTP you need to have mailutils and mpack installed sudo apt update sudo apt-get install mailutils sudo apt-get install mpack now to send an attachment you would use mpack like this mpack -s "Put the subject in in here" -d /home/pi/message.txt /home/pi/image.jpg ...
by pcmanbob
Sun Nov 17, 2019 10:13 am
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 308

Re: 8ch relay 12V

If every thing works correctly the way you have it connected then you can use the ULN2803A between the pi gpio and the relay board. connected like this https://i.imgur.com/eJBUtSA.jpg you can of course use any gpio pins you want , but you must use a ULN2803A the A variant being suitable for use with...
by pcmanbob
Sat Nov 16, 2019 11:41 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 308

Re: 8ch relay 12V

Ok try this.

Connect 12V supply to vcc and ground.

Connect 5V to com and the ground form the supply to IN pin

You should see the LED light up and the relay should click.

You need the 12V to actually power the relay coils.
by pcmanbob
Sat Nov 16, 2019 9:28 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 308

Re: 8ch relay 12V

See above I edited my post....
by pcmanbob
Sat Nov 16, 2019 9:17 pm
Forum: Automation, sensing and robotics
Topic: 8ch relay 12V
Replies: 15
Views: 308

Re: 8ch relay 12V

It very much depends upon the operating mode of the relay board. If your diagram is correct then it would suggest you need to supply a voltage to the In pins and the board has a common ground, in which case no you can't use a uln2803 as that chip provides a ground on each output that is switched by ...
by pcmanbob
Sat Nov 16, 2019 5:43 pm
Forum: Beginners
Topic: CamJam Edukit - Worksheets for connecting wires?
Replies: 2
Views: 67

Re: CamJam Edukit - Worksheets for connecting wires?

Hi.

If you are struggling with the parts you have not matching the instructions you are probably best posting pictures of the parts you have and explaining what you don't understand in more detail.

Then we will probably have a better chance of helping.
by pcmanbob
Fri Nov 15, 2019 10:22 pm
Forum: General discussion
Topic: MCP4725 DAC with LCD issues
Replies: 44
Views: 1284

Re: MCP4725 DAC with LCD issues

The problem is not the interface but the driver software, the software supports both I2C and direct gpio control. The problem is that the adafruit driver no longer works so even if an I2C interface was being used it still wouldn't have worked. The driver I suggested RPLCD again supports both I2C and...
by pcmanbob
Fri Nov 15, 2019 2:51 pm
Forum: Troubleshooting
Topic: Cannot setup SSMTP properly to send mail via SMTP Gmail
Replies: 56
Views: 804

Re: Cannot setup SSMTP properly to send mail via SMTP Gmail

This thread has the details on setting up MSMTP,

https://www.raspberrypi.org/forums/view ... &p=1498580

You can use mailutils and mpack with MSMTP in exactly the same way as you would with SSMTP
by pcmanbob
Fri Nov 15, 2019 1:20 pm
Forum: Troubleshooting
Topic: Cannot setup SSMTP properly to send mail via SMTP Gmail
Replies: 56
Views: 804

Re: Cannot setup SSMTP properly to send mail via SMTP Gmail

Hi.

Which OS are you trying to run SSMTP on ?

SSMTP will not work on buster you have to switch to MSMTP
by pcmanbob
Fri Nov 15, 2019 1:15 pm
Forum: Python
Topic: Guizero liblary problem
Replies: 1
Views: 61

Re: Guizero liblary problem

Hi. Looking at your image I don't see an error it appears to be the output of an OS update. I suggest you look at the image you have posted and actually post an image of the error, better still just copy the error output and past the test directly in to your post. You might also want to post your co...
by pcmanbob
Fri Nov 15, 2019 10:32 am
Forum: General discussion
Topic: Time and date indicated by Raspberry Pi
Replies: 7
Views: 333

Re: Time and date indicated by Raspberry Pi

If you run this at the command line it should set your date/time to the correct values sudo date -s "$(wget -qSO- --max-redirect=0 google.com 2>&1 | grep Date: | cut -d' ' -f5-8)Z" You can use this a a work round until you provide the details requested so we can help figure out why the standard time...
by pcmanbob
Fri Nov 15, 2019 9:50 am
Forum: Advanced users
Topic: Power via POE pins
Replies: 6
Views: 200

Re: Power via POE pins

Hi.

As far as I am aware the 4 new pins are for Ethernet connections not power.
The voltage conversion is done on the HAT board and then the 5V is fed into the 5V GPIO pin 2 or 4.

edit....
as discussed in this thread https://www.raspberrypi.org/forums/view ... p?t=208093
by pcmanbob
Thu Nov 14, 2019 8:25 pm
Forum: General discussion
Topic: pi to pi peer to peer
Replies: 2
Views: 102

Re: pi to pi peer to peer

Yes you can connect 2 X pi's using just a normal LAN cable , then set a static IP one each pi and you will have a network consisting of just the 2 pi's.

See this thread https://www.raspberrypi.org/forums/view ... 1&t=255515
My post explains how to set the 2 static IP's on the pi's
by pcmanbob
Thu Nov 14, 2019 8:12 pm
Forum: Troubleshooting
Topic: Changing OS
Replies: 4
Views: 118

Re: Changing OS

So here is my problem. My raspberry pi 3b+ is running kali. However I've forgotten my password (haven't used it for a year). I have flashed another SD card, with ubuntu mate image, however everytime I'm starting raspberry, it goes straight to kali. I've tried holding the shift key as I've read on i...
by pcmanbob
Thu Nov 14, 2019 6:35 pm
Forum: Automation, sensing and robotics
Topic: 12v DC proximity detector for use on truck (2-3 feet range)
Replies: 12
Views: 289

Re: 12v DC proximity detector for use on truck (2-3 feet range)

As I said a PIR detects heat , like a human body so a vehicle may not trigger a PIR unless it warm compared to the background. You would need to do your own texting to see if a reversing truck/trailer would trigger it, they also work best if the object moves across the sensor field rather than towar...
by pcmanbob
Thu Nov 14, 2019 5:33 pm
Forum: Automation, sensing and robotics
Topic: 12v DC proximity detector for use on truck (2-3 feet range)
Replies: 12
Views: 289

Re: 12v DC proximity detector for use on truck (2-3 feet range)

25cm is the minimum range , so you can't measure distance to object under 25cm .

I don't know the maximum range but I would guess several meters.

So 2-3ft would be 60-90cm well with in the operating range of the sensor ,
So why won't that be suitable ?
by pcmanbob
Thu Nov 14, 2019 3:56 pm
Forum: Automation, sensing and robotics
Topic: 12v DC proximity detector for use on truck (2-3 feet range)
Replies: 12
Views: 289

Re: 12v DC proximity detector for use on truck (2-3 feet range)

Hi. Al the PIR's I have seen all use the high/low output, to signal if a warm body has passed through their field of detection, they will only detect a heat source like a person , so a vehicle may or may not be detected depending on it temperature compared to the surrounding air temperature. if you ...
by pcmanbob
Thu Nov 14, 2019 1:09 pm
Forum: General discussion
Topic: Proper shutdown
Replies: 27
Views: 619

Re: Proper shutdown

Think about it,

I you just pull the power or the power fails leading to an improper shutdown then will be no record of it in the logs, no power means pi just stops , OS stops nothing gets written to logs.
by pcmanbob
Wed Nov 13, 2019 10:25 am
Forum: General discussion
Topic: gpio mode that lcd 3.5 tft used?
Replies: 1
Views: 58

Re: gpio mode that lcd 3.5 tft used?

Hi.

Please repost your link as the one posted does not work.
by pcmanbob
Wed Nov 13, 2019 10:21 am
Forum: Advanced users
Topic: Raspberry pie 3 A+ and 9v fans
Replies: 8
Views: 221

Re: Raspberry pie 3 A+ and 9v fans

An L7805 is only rated for 1A, you may find it underrated when trying to power a pi3A+ depending on what else is attached to it.

they are also very inefficient produce a lot of heat to convert 12v to 5v , you would do better to look for a DC-DC buck converter based on the LM2596

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