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by Z80 Refugee
Thu Jul 12, 2018 10:02 pm
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 4333

Re: Controlling homemade solenoids using Rpi Z W

I think you are mistaken there. Take another look at the Fritzing diagram. The button is shown with a black wire to the blue rail of the breadboard and that rail is shown connected to GND on the Pi header. The other side of the switch has a blue wire going to the gpio input and a pullup resistor. I...
by Z80 Refugee
Thu Jul 12, 2018 5:27 pm
Forum: General discussion
Topic: Not just for kids
Replies: 3
Views: 2706

Re: Not just for kids

Great idea.
by Z80 Refugee
Thu Jul 12, 2018 5:23 pm
Forum: Python
Topic: GPIO LED not Working
Replies: 9
Views: 644

Re: GPIO LED not Working

rpiMike wrote:
Wed Jul 11, 2018 6:59 pm
Can't tell from your photos how its wired. That led looks huge - what specification is it.
It's just an ordinary LED in an 8 or 10mm package. Nothing to worry about (probably). The resistor might be 330 ohms, not too clear. Dunno how the switches are wired up though!
by Z80 Refugee
Thu Jul 12, 2018 5:16 pm
Forum: Automation, sensing and robotics
Topic: Two 6V motors through RPi3B
Replies: 19
Views: 1507

Re: Two 6V motors through RPi3B

Burngate wrote:
Thu Jul 12, 2018 10:34 am
The device in the picture is L293D which has the diodes in-built.
Oh yes, so they are. Thanks.
by Z80 Refugee
Thu Jul 12, 2018 5:15 pm
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 4333

Re: Controlling homemade solenoids using Rpi Z W

PiGraham wrote:
Thu Jul 12, 2018 10:06 am
They are connecting 5V to one side of the solenoid coils and the switch pull-up.
That's not correct. Read what I had to say about it (immediately above your post).
by Z80 Refugee
Thu Jul 12, 2018 5:13 pm
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 4333

Re: Controlling homemade solenoids using Rpi Z W

With an engineer's wet finger, I would say they need to actuate in about 0.1 seconds to reasonably impress. If it took a second to move up or down, it wouldn't look right.
by Z80 Refugee
Thu Jul 12, 2018 5:09 pm
Forum: HATs and other add-ons
Topic: Relay' connected to Rpi Zero W - causes it to freeze
Replies: 29
Views: 2886

Re: Relay' connected to Rpi Zero W - causes it to freeze

As suggested - I tried to power the relay ( instead of pi's 5V ), with external power supply: Relay was powered correctly ( green led was ON )- but switching was not done ( voltage difference of 3.8 between trigger GPIO connected on relay to GND on relay ). That very much suggests the relay module ...
by Z80 Refugee
Thu Jul 12, 2018 9:18 am
Forum: Automation, sensing and robotics
Topic: Two 6V motors through RPi3B
Replies: 19
Views: 1507

Re: Two 6V motors through RPi3B

Can we use circuit diagrams please? AFF8B906-7B02-4121-B7CF-3DFF36582AF7.jpeg Here is the L293D datasheet: http://www.ti.com/lit/ds/symlink/l293d.pdf (there is an obvious error in section 6.3: for "Low-level output voltage" read "Low-level input voltage"). The chip uses a 5V supply for the logic, bu...
by Z80 Refugee
Thu Jul 12, 2018 7:44 am
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 4333

Re: Controlling homemade solenoids using Rpi Z W

1. Create a solenoid using thinner wires. If we do this, would creating a solenoid that would have internal resistance of 330ohms mean that the 3.3 gpio pin with its 16maH current would be enough to move a pin? The question is whether 50mW (the maximum power available from a GPIO pin, = 3.3v x 16mA...
by Z80 Refugee
Wed Jul 11, 2018 10:06 pm
Forum: HATs and other add-ons
Topic: Relay' connected to Rpi Zero W - causes it to freeze
Replies: 29
Views: 2886

Re: Relay' connected to Rpi Zero W - causes it to freeze

2. relay is connected directly to RPI ( 5V to VCC, GND to GND, GPIO20, to relay signal ) What? Is this just a relay, or does it have some electronics as well? How do you know the electronics is suitable for the RPi (relay modules designed for Arduino are not)? I've only been on this forum for a few...
by Z80 Refugee
Wed Jul 11, 2018 9:57 pm
Forum: Python
Topic: GPIO LED not Working
Replies: 9
Views: 644

Re: GPIO LED not Working

I am using a LED on my Raspberry Pi 3. I am trying to simply get it to toggle because it is not working properly. I have tried different pins and different resistance strengths, but I cannot get it to work at all. I believe it is a hardware issue so if anybody can help me with that that would be gr...
by Z80 Refugee
Wed Jul 11, 2018 9:52 pm
Forum: Automation, sensing and robotics
Topic: Controlling homemade solenoids using Rpi Z W
Replies: 53
Views: 4333

Re: Controlling homemade solenoids using Rpi Z W

So we took a stupid risk and tried connecting the homemade solenoid to the pi without a resistor and surprisingly it didn't do anything. The 3 volt battery was able to move the pin so isn't the 3.3v gpio pin supposed to be enough? You don't understand enough about what you are trying to do. Every e...
by Z80 Refugee
Wed Jul 11, 2018 7:19 am
Forum: Automation, sensing and robotics
Topic: Low voltage relay switch
Replies: 1
Views: 206

Re: Low voltage relay switch

Please be more specific about what you are trying to accomplish. A diagram will help.
by Z80 Refugee
Wed Jul 11, 2018 7:17 am
Forum: Troubleshooting
Topic: Problem with GPIO pins
Replies: 28
Views: 2637

Re: Problem with GPIO pins

You can't kill an I/O pin just by controlling a different one, there has to have been an incorrect physical connection. Now, if I might digress, I don't understand this WiringPi numbering business. For my Forth tutorial I use WiringPi for the GPIO control, and I had no trouble using pin assignments ...
by Z80 Refugee
Tue Jul 10, 2018 5:10 pm
Forum: Troubleshooting
Topic: Problem with GPIO pins
Replies: 28
Views: 2637

Re: Problem with GPIO pins

Bloody pictorials! I read (and understand) circuit diagrams.
by Z80 Refugee
Tue Jul 10, 2018 5:07 pm
Forum: Automation, sensing and robotics
Topic: How to properly connect many interrupters with internal pull-up resistors and long wires?
Replies: 11
Views: 795

Re: How to properly connect many interrupters with internal pull-up resistors and long wires?

(see my previous link to suggested component values - never, ever, rely on internal pull-ups for anything that matters). Sorry I don't see your previous link. Can you send it again? I am interested in better components for physical connections. Apologies, I was thinking of a different thread. Begin...
by Z80 Refugee
Tue Jul 10, 2018 2:13 pm
Forum: General discussion
Topic: Thinking of writing a technical FAQ
Replies: 53
Views: 3109

Re: Thinking of writing a technical FAQ

Obviously I was being deliberately dramatic! However, the unsuitability of shields (and other boards such as relays) designed for Arduino should be in big letters.
by Z80 Refugee
Tue Jul 10, 2018 2:01 pm
Forum: Automation, sensing and robotics
Topic: How to properly connect many interrupters with internal pull-up resistors and long wires?
Replies: 11
Views: 795

Re: How to properly connect many interrupters with internal pull-up resistors and long wires?

Your cable management leaves a great deal to be desired. Messy is difficult to fault-find and maintain, tidy takes time at the outset but pays dividends long-term. Note this picture was taken while I was working on the installation but it looks better when the derivation boxes are closed (and the c...
by Z80 Refugee
Tue Jul 10, 2018 1:47 pm
Forum: Troubleshooting
Topic: Problem with GPIO pins
Replies: 28
Views: 2637

Re: Problem with GPIO pins

But since you have not given any details of how the motor was connected when it ran in Python, we can't offer an opinion whether it was safe or a ticking time bomb.
by Z80 Refugee
Tue Jul 10, 2018 1:45 pm
Forum: General discussion
Topic: Thinking of writing a technical FAQ
Replies: 53
Views: 3109

Re: Thinking of writing a technical FAQ

There's gotta be something about not just connecting the GPIO to a mains bulb!
by Z80 Refugee
Tue Jul 10, 2018 12:32 pm
Forum: Beginners
Topic: Access Raspberry Pi outside of local network, without port forwarding or third party software
Replies: 10
Views: 6032

Re: Access Raspberry Pi outside of local network, without port forwarding or third party software

I was going through my router settings and I was not able to find anything about port forwarding That may be because you are using the free router supplied by the likes of BT with your broadband package. Typically, settings like that are locked down and not made available via the web admin interfac...
by Z80 Refugee
Tue Jul 10, 2018 11:43 am
Forum: Automation, sensing and robotics
Topic: Two 6V motors through RPi3B
Replies: 19
Views: 1507

Re: Two 6V motors through RPi3B

3NiGMa wrote:
Tue Jul 10, 2018 9:04 am
A lot of forums say four AA alkaline batteries will not be enough
Not enough for what? Running the motors and the RPi from the same supply? No. Run the RPi from a different supply, or you will have a lot of trouble.
by Z80 Refugee
Tue Jul 10, 2018 11:39 am
Forum: Troubleshooting
Topic: Problem with GPIO pins
Replies: 28
Views: 2637

Re: Problem with GPIO pins

Are these pins permanently damaged? No reason to think otherwise (I assume you ran the test with nothing connected, as you were instructed). And what caused it ? How would we know? We don't know what you've done (deliberately or accidentally). Read this: Beginners Guide to Wiring Things to the GPIO
by Z80 Refugee
Tue Jul 10, 2018 11:34 am
Forum: Automation, sensing and robotics
Topic: How to properly connect many interrupters with internal pull-up resistors and long wires?
Replies: 11
Views: 795

Re: How to properly connect many interrupters with internal pull-up resistors and long wires?

Your cable management leaves a great deal to be desired. Messy is difficult to fault-find and maintain, tidy takes time at the outset but pays dividends long-term.
by Z80 Refugee
Tue Jul 10, 2018 7:41 am
Forum: Beginners
Topic: XC4629 Display Module and pi zero
Replies: 2
Views: 255

Re: OLED and pi zero

Do I need specific wires? As in do I need wires that have specific functions? Or can I use normal wires? Just wires, and it doesn't matter what colour they are either. But keep them short - half a metre should be no problem. I find solid-core telephone or alarm wire a convenient source of cheap and...

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