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by pcmanbob
Sat Sep 21, 2019 6:18 pm
Forum: Troubleshooting
Topic: RPI4B not working pls help
Replies: 1
Views: 46

Re: RPI4B not working pls help

Hi.

I suggest you go read the " Is your Pi not booting? (The Boot Problems Sticky) " , there is a page specifically on the pi4B not booting.


https://www.raspberrypi.org/forums/view ... 28&t=58151
by pcmanbob
Sat Sep 21, 2019 6:15 pm
Forum: Python
Topic: Using a ultra sonic senso to play sound
Replies: 1
Views: 43

Re: Using a ultra sonic senso to play sound

Hi. adding an if statement is simple enough there are lots of examples on line , this is just one i picked at random https://www.w3schools.com/python/python_conditions.asp so in your code it would look like this import RPi.GPIO as GPIO import os import time GPIO.setmode(GPIO.BCM) TRIG = 23 ECHO = 24...
by pcmanbob
Sat Sep 21, 2019 2:30 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADXL345 SPI interfacing on Raspberry pi
Replies: 5
Views: 80

Re: ADXL345 SPI interfacing on Raspberry pi

Then I would suggest you ask the author for help as I guess it will need a change to the library you are using.

You might find asking on the adafruit forum will get you the help you need .

https://forums.adafruit.com/
by pcmanbob
Sat Sep 21, 2019 2:22 pm
Forum: General discussion
Topic: Need 12vdc input to Optoisolator to Gpio connection
Replies: 26
Views: 2146

Re: Need 12vdc input to Optoisolator to Gpio connection

You would be better using a resistor for each opto isolator and putting the common feed connection before the resistors. If you have just one opto isolator turned on with a single resistor then it will work , but if both are turned on , you may find nether will work due to the reduce voltage/current...
by pcmanbob
Sat Sep 21, 2019 1:58 pm
Forum: Beginners
Topic: Just got my first Pi !
Replies: 8
Views: 171

Re: Just got my first Pi !

Hi. If you are trying to set you new pi up without using a screen and keyboard then you can't use noobs to do it , as noobs is just an installer and requires interaction using a screen and keyboard. Get yourself another SD card 16GB will be fine, then using a desktop PC , download the raspbian image...
by pcmanbob
Sat Sep 21, 2019 1:40 pm
Forum: Beginners
Topic: Ultrasonic and servo motor - adafruit dc and stepper motor hat - mini kit
Replies: 6
Views: 70

Re: Ultrasonic and servo motor - adafruit dc and stepper motor hat - mini kit

sorry for the repeated question. I am pretty new to this. Talking in forums and using Pi. Its not a problem the forum can be hard to search for something if you don't know exactly what you are searching for, even then you don't always find it. I did not even bother searching for the original post m...
by pcmanbob
Sat Sep 21, 2019 1:20 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADXL345 SPI interfacing on Raspberry pi
Replies: 5
Views: 80

Re: ADXL345 SPI interfacing on Raspberry pi

You would need to make the address change in which ever program you are using to access your ADXL345 accelerometer's,

so that the program accesses one, then changes the address and accesses the other , each in turn.
by pcmanbob
Sat Sep 21, 2019 12:37 pm
Forum: Troubleshooting
Topic: Rasp Pi 4 B
Replies: 1
Views: 86

Re: Rasp Pi 4 B

Hi.

I suggest you go read the " Is your Pi not booting? (The Boot Problems Sticky) " , there is a page specifically on the pi4B not booting.

https://www.raspberrypi.org/forums/view ... 28&t=58151
by pcmanbob
Sat Sep 21, 2019 9:53 am
Forum: Troubleshooting
Topic: Raspberry pi Low voltage on GPIO Pins
Replies: 8
Views: 165

Re: Raspberry pi Low voltage on GPIO Pins

Most people interpret R18 as 0.18 ohms. Its just the way the component is set up in the cad software I am using I will have to see if I can edit the component to remove the R and add the ohms symbol. Edit. adding Ω to component value makes it look like 10 so even more confusing, will have to just d...
by pcmanbob
Sat Sep 21, 2019 9:29 am
Forum: Beginners
Topic: Raspberry Pi and Relay safety question
Replies: 4
Views: 100

Re: Raspberry Pi and Relay safety question

So if your relay board is active low , ( setting gpio low turns relay & LED on ) then you could use the ULN2803A, as you don't need any other components as the ULN2803A is design to be driven directly via a 3.3v input. You must use the ULN2803A the A variant is the one for 3.3v inputs , other varian...
by pcmanbob
Sat Sep 21, 2019 9:03 am
Forum: Beginners
Topic: Ultrasonic and servo motor - adafruit dc and stepper motor hat - mini kit
Replies: 6
Views: 70

Re: Ultrasonic and servo motor - adafruit dc and stepper motor hat - mini kit

This question has been asked before about this motor driver board.

Image

So the green arrow is pointing to a row of connections that are all the unused gpio pins that you can use to connect your servo and sensor.
by pcmanbob
Sat Sep 21, 2019 8:44 am
Forum: Beginners
Topic: Ultrasonic and servo motor - adafruit dc and stepper motor hat - mini kit
Replies: 6
Views: 70

Re: Ultrasonic and servo motor - adafruit dc and stepper motor hat - mini kit

Which motor hat are you using ?

posting a link to it might help people help you , as we cant see your pi.
by pcmanbob
Fri Sep 20, 2019 8:25 pm
Forum: Automation, sensing and robotics
Topic: Pi Zero W motor hookup
Replies: 1
Views: 29

Re: Pi Zero W motor hookup

Hi.

So looking up the TB6612 on the adafruit site I could only find the following connections marked
ani1, ain2, bin1, bin2, pwma, pwmb, stby, gnd, vcc, vm, motora, motorb.

No mention of i2c or spi

So it might help if you post a link to the board you have.
by pcmanbob
Fri Sep 20, 2019 8:14 pm
Forum: Troubleshooting
Topic: Please help i am not able to update or install anything new on my raspbian
Replies: 1
Views: 68

Re: Please help i am not able to update or install anything new on my raspbian

The error could not resolve host looks like a DNS failure or no internet connection

What happens if you try

ping google.com
and
ping 8.8.8.8
by pcmanbob
Fri Sep 20, 2019 5:29 pm
Forum: Beginners
Topic: Raspberry Pi and Relay safety question
Replies: 4
Views: 100

Re: Raspberry Pi and Relay safety question

Hi. So the fist thing we need to know is , is the relay board control input an active high or active low. So in your program did you set the gpio to be high or low to switch the relay on ? That will decide which of the options you need to use to interface you pi to the relay board. But I can tell yo...
by pcmanbob
Fri Sep 20, 2019 5:03 pm
Forum: General discussion
Topic: posting or replies blocked [SOLVED]
Replies: 13
Views: 264

Re: posting or replies blocked [SOLVED]

That was the only change I made to the code I was posting , but it could be that changes to the filter happened while I was changing the code and the variable name change had nothing to do with it.

Guess we will never know.
by pcmanbob
Fri Sep 20, 2019 4:01 pm
Forum: Troubleshooting
Topic: Break endless video loop
Replies: 4
Views: 55

Re: Break endless video loop

You should be able to break the loop if you have a keyboard attached by hitting ctrl-C. I don't think that wont work as cron is running in a different environment to the command line and its also running in the background. but the " killall omxplayer " should work but if not try running it with " s...
by pcmanbob
Fri Sep 20, 2019 2:31 pm
Forum: Beginners
Topic: Running vibration motors with pi zero w
Replies: 5
Views: 1400

Re: Running vibration motors with pi zero w

Hi, Even my needs involve using a vibration motor, I am cluless at what value should the resistor be and do I need the transistor. Could somebody help me to? Details: Here are the specification Voltage Range: DC 2.5-4V. Motor Diameter: 10 mm. Motor Thickness: 3.4 mm. Min. Rated Speed: 9000RPM Max. ...
by pcmanbob
Fri Sep 20, 2019 2:29 pm
Forum: Troubleshooting
Topic: Break endless video loop
Replies: 4
Views: 55

Re: Break endless video loop

Hi. Yes there is. remove the SD card from the powered off pi put it back in to your PC , once windows detects it do not allow windows to format it if offered. Windows should open the fat partition for your, so all you need to do is create a file called ssh.txt. Then put your SD card back in the pi a...
by pcmanbob
Fri Sep 20, 2019 2:19 pm
Forum: Troubleshooting
Topic: Raspberry pi Low voltage on GPIO Pins
Replies: 8
Views: 165

Re: Raspberry pi Low voltage on GPIO Pins

Hi. So your vibration motor has a rated current of 90mA QUICK OVERVIEW Voltage Range: DC 2.5-4V. Motor Diameter: 10 mm. Motor Thickness: 3.4 mm. Min. Rated Speed: 9000RPM Max. Rated Current: 90mA and as jamesh has already said a gpio pin can only supply 16mA so you will need to connect using a trans...
by pcmanbob
Fri Sep 20, 2019 1:35 pm
Forum: General discussion
Topic: posting or replies blocked [SOLVED]
Replies: 13
Views: 264

Re: posting or replies blocked

Thanks ShiftPlusOne

May be I did not need to change the variable name after all , guess they changed things while I was attempting to post.
by pcmanbob
Fri Sep 20, 2019 1:22 pm
Forum: General discussion
Topic: posting or replies blocked [SOLVED]
Replies: 13
Views: 264

Re: posting or replies blocked

ShiftPlusOne wrote:
Fri Sep 20, 2019 1:08 pm
I've passed it on to the web team.
thanks ShiftPlusOne. please see my edit , repeated here too.
So I finally got it to post all I changed was was all references to phValue to phvalue in the code
by pcmanbob
Fri Sep 20, 2019 1:17 pm
Forum: General discussion
Topic: DFRobot pH Meter V1. 1 with Raspberry Pi 3 B+
Replies: 8
Views: 197

Re: DFRobot pH Meter V1. 1 with Raspberry Pi 3 B+

So this is the code after changing one variable name so it will allow me to post it. import spidev import RPi.GPIO as GPIO import time import sys GPIO.setmode(GPIO.BCM) GPIO.setwarnings(False) GPIO.setup(21, GPIO.OUT) servo = GPIO.PWM(21, 50) servo.start(2.5) spi = spidev.SpiDev() # create spi objec...
by pcmanbob
Fri Sep 20, 2019 1:04 pm
Forum: General discussion
Topic: posting or replies blocked [SOLVED]
Replies: 13
Views: 264

Re: posting or replies blocked

So after some more testing I can post simple text but any attempt to post code even a simple print statement in code tags results in the post being blocked with the above error. yet it works ok in this thread print ("test") Edit ... So I finally got it to post all I changed was was all references to...
by pcmanbob
Fri Sep 20, 2019 12:59 pm
Forum: General discussion
Topic: DFRobot pH Meter V1. 1 with Raspberry Pi 3 B+
Replies: 8
Views: 197

Re: DFRobot pH Meter V1. 1 with Raspberry Pi 3 B+

So by following some of the documentation links I think I have figured out how to convert the voltage to a PH value. This is only a guess so you will have to check the calibration as pre the instructions in one of your linked documents. but at the moment I can post the code because any attempt to po...

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