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by SmokeySpace
Thu Jul 23, 2020 6:54 am
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Re: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

I did test the same pin (I switched to GPIO pin 6 to see if maybe it would work) with a simple LED circuit, which worked perfectly. ... Also I'm using male to female breadboard wires. Don't look like female Dupont in the photo but not that clear. Personally I avoid those plug boards like the plague...
by SmokeySpace
Wed Jul 22, 2020 6:00 pm
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Re: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

I will ask a basic question. How are you exposing it to a magnet? I assuming waving a small magnet around it? Make sure you try multiple magnet orientations on different sides of the sensor. I have a small magnetic encoder disk that I wave on every side, its definitely magnetic too they stick to ea...
by SmokeySpace
Wed Jul 22, 2020 5:59 pm
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Re: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

As the A3144 has an open collector output , I would power it with 5V and ground , but then I would use a 10K resistor between the output and 3.3V to act as the pull-up, this way you can safely connect the out put directly to a gpio pin. Hmm I tried that, but it didn't seem to work, here is the circ...
by SmokeySpace
Wed Jul 22, 2020 7:04 am
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Re: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

to do it correctly, would I just use the internal pull up right? I thought about using a voltage divider as well to get 3.3v from the 5v. I use these parts for many projects including e-bike motors, tachs, end-stops, etc and over the years found the need to interface to STM32 which has same voltage...
by SmokeySpace
Tue Jul 21, 2020 8:08 pm
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Re: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

Looking at the picture of your wiring you appear to using a 5V pull up on the output of the hall affect sensor, the pi gpio is only 3.3V and is not 5V tolerant. So you may well have damaged you pi gpio. Yes and that is what I thought, I can't remember if I actually tested it with 5v and physical pu...
by SmokeySpace
Tue Jul 21, 2020 6:33 pm
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Re: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

Can you show a schematics of your wiring? IMG_2169.JPG I am using the same circuit he is, but I also tried using a 3K resistance (I found this at a different source) and also tried no physical resistor, just relying on the internal one, with no luck. Although I was using my old Pi that is damaged, ...
by SmokeySpace
Tue Jul 21, 2020 9:51 am
Forum: Automation, sensing and robotics
Topic: Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+
Replies: 16
Views: 946

Hall Effect Sensor (A3144) not working with Raspberry Pi 3B+

I'm using this circuit and code for a hall effect magnetic sensor - https://www.raspberrypi-spy.co.uk/2015/09/how-to-use-a-hall-effect-sensor-with-the-raspberry-pi/ but it never seems to detect the magnet, although I see he is using a pull up resistor and also declaring the pin with a pull up resist...
by SmokeySpace
Thu Jan 23, 2020 4:19 am
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi GPIO Range Sensor Pins Stopped Working

Well that's what's killing your gpio pins and will probably result in your pi failing some time in the future. If you are getting 5v out of the potential divider then you don't have it wired correctly on the PCB. if you post picture of both the front and back of the PCB we might spot your error , b...
by SmokeySpace
Wed Jan 22, 2020 12:58 am
Forum: Troubleshooting
Topic: GPIO Pins Stop Working
Replies: 2
Views: 360

Re: GPIO Pins Stop Working

by SmokeySpace
Tue Jan 21, 2020 10:12 pm
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi GPIO Range Sensor Pins Stopped Working

I have not I am a bit confused on how to do that from your previous explanation Disconnect you potential divider circuits on the PCB from the pi and the sensors then connect each one to your pi and you volt meter like this https://i.imgur.com/iNR8gx5.jpg you should get a reading of 3.3V Ok, thank y...
by SmokeySpace
Mon Jan 20, 2020 11:31 pm
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi GPIO Range Sensor Pins Stopped Working

I would suggest you test your potential divider circuits to prove they are wired correctly. disconnect all wires from the gpio Connect the ground on the potential divider to be test and connect the wire that went to echo pin to 5V pin on gpio header , now using volt meter measure output on wire fro...
by SmokeySpace
Mon Jan 20, 2020 7:00 pm
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi GPIO Range Sensor Pins Stopped Working

All I did was a quick test with a digital voltmeter on the trig pin with the sensor powered, to see if 5V was being applied to the pin, no pi involved. As the gpio pin connected to trig would be an output the would be no pull up/down involved. I think if the trig pin was causing a problem we would ...
by SmokeySpace
Mon Jan 20, 2020 3:22 am
Forum: Troubleshooting
Topic: GPIO Pins Stop Working
Replies: 2
Views: 360

GPIO Pins Stop Working

I made a previous post about the range sensors connected to my Raspberry Pi B not working, however I have figured out that it is the pins that stop working. I'm using a HC-S0R4 ultrasonic range sensor with the proper voltage divider (shown below) with no luck. Anytime the sensor is bumped or just ra...
by SmokeySpace
Sun Jan 19, 2020 5:58 pm
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi Range Sensor Stopped Working

pcmanbob wrote:
Sun Jan 19, 2020 5:53 pm
What value are the resistors you are using on the PCB the brown looks like 1K, but I can't see what value the blue on is.
The blue one is 2K, I’ve also tested both with a multimeter

Edit - I’ve also checked all the connections on the PCB with the multimeter, everything is good
by SmokeySpace
Sun Jan 19, 2020 5:12 pm
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi Range Sensor Stopped Working

Well if you are damaging gpio pins then I suspect you don't have the potential divider circuit set up correctly. Try posting a picture of your potential divider circuit on both your bread board and your PCB, may be we can spot some error in your layout. https://www.raspberrypi.org/forums/download/f...
by SmokeySpace
Sun Jan 19, 2020 2:16 pm
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Re: Raspberry Pi Range Sensor Stopped Working

So my first question is are these 5V powered HC-S0R4 Ultrasonic range sensors ? If so have you got a potential divider circuit on the output to protect the pi gpio from the 5V output ? So do both sensors work if you connect each to the good sensors wiring in turn ? If so it would suggest a problem ...
by SmokeySpace
Sun Jan 19, 2020 2:57 am
Forum: Troubleshooting
Topic: Raspberry Pi GPIO Range Sensor Pins Stopped Working
Replies: 19
Views: 1224

Raspberry Pi GPIO Range Sensor Pins Stopped Working

EDIT 2 - I got it to work by switching the pins a third time, so now my question is why do the pins stop working? I have 2 HC-S0R4 Ultrasonic range sensors hooked up to my Raspberry Pi B, and earlier today I had both of them working perfectly, but after a bit of testing one of them stopped working a...
by SmokeySpace
Tue Sep 17, 2019 3:44 pm
Forum: Automation, sensing and robotics
Topic: How Many Sensors/Motors Can a Raspberry Pi 3 Handle at Once?
Replies: 6
Views: 1203

Re: How Many Sensors/Motors Can a Raspberry Pi 3 Handle at Once?

You are only taking about sending high or low signals to the H-bridge so a mA or 2 at most per gpio pin, same goes for the servo pwm signal for control , you should be able to power a small servo like the SG90, from the 5v gpio pin , probably 200mA max, range sensor assuming HC-SR04 15mA per sensor...
by SmokeySpace
Tue Sep 17, 2019 12:57 pm
Forum: Automation, sensing and robotics
Topic: How Many Sensors/Motors Can a Raspberry Pi 3 Handle at Once?
Replies: 6
Views: 1203

Re: How Many Sensors/Motors Can a Raspberry Pi 3 Handle at Once?

Hi. You can work this out for yourself, The pi has 26 possible gpio pins for use , you just need to add up how many gpio pins you need for each device H-bridge = 6 range sensor = 2 for 3 sensors = 6 servo = 1 total 13 so you still have 13 gpio left its as simple as that. Ok that makes sense, but is...
by SmokeySpace
Mon Sep 16, 2019 10:58 pm
Forum: Automation, sensing and robotics
Topic: How Many Sensors/Motors Can a Raspberry Pi 3 Handle at Once?
Replies: 6
Views: 1203

How Many Sensors/Motors Can a Raspberry Pi 3 Handle at Once?

I'm building a robot with the Raspberry Pi 3 and I have 2 small 3-6v DC motors with wheels hooked up to an H Bridge Motor Drive Controller (powered separately with a 9 volt battery) and I also want to be able to have the robot see around itself as its driving with the motors, whether this is with 3 ...

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