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by SavagePi
Mon May 19, 2014 7:51 pm
Forum: Automation, sensing and robotics
Topic: My Pi Car - It's a start!
Replies: 7
Views: 2027

Re: My Pi Car - It's a start!

On the L298N you have used 6 GPIO pins to run the motors, you could link the enable pins and just use the Input pins, saving yourself 2 GPIOs (but if you have enough GPIO's then don't worry about it). Sorry, Doug. I didn't explain the situation fully. Please see the explanation in my other post... ...
by SavagePi
Mon May 19, 2014 7:24 pm
Forum: Automation, sensing and robotics
Topic: Quadrocopter
Replies: 3
Views: 802

Re: Quadrocopter

I'm pretty new to the RPi too, and a complete novice to Python programming. However, I've just finished my first project, which is an autonomous remote controlled car... http://www.raspberrypi.org/forums/viewtopic.php?f=37&t=77111 Being a novice, this was quite intensive for me - but extremely enjoy...
by SavagePi
Mon May 19, 2014 4:39 pm
Forum: Automation, sensing and robotics
Topic: Problems with the HC-SR04 Ultrasonic Sensor
Replies: 15
Views: 16941

Re: Problems with the HC-SR04 Ultrasonic Sensor

Sorry, I didn't clarify my connections. The sensor is connected to the +5V supply and I have a 4K7 resistor in series with the 'echo' pin and the GPIO port on the RPi. This limits the current to a safe level for the GPIO ports. There's no need for a potential divider at small voltage differences suc...
by SavagePi
Sun May 18, 2014 9:11 pm
Forum: Automation, sensing and robotics
Topic: Problems with the HC-SR04 Ultrasonic Sensor
Replies: 15
Views: 16941

Problems with the HC-SR04 Ultrasonic Sensor

Have you been having problems using the HC-SR04 Ultrasonic Distance Sensor? So have I. And after some intensive testing (you'll need a dual beam oscilloscope to see this properly), here's what I've discovered... It suffers from some inherent built-in flaws. One of which is where the receiver picks u...
by SavagePi
Sun May 18, 2014 8:09 pm
Forum: Automation, sensing and robotics
Topic: My Pi Car - It's a start!
Replies: 7
Views: 2027

Re: My Pi Car - It's a start!

I am using the HC-SR04 sensor. But it's got so many built-in flaws I needed to connect it to my oscilloscope to see how it was (or wasn't) working. After analysing the signals I reaslised the HC-SR04 suffers badly from crosstalk, whereby the receiver picks up the signal from the transmitter before t...
by SavagePi
Tue May 13, 2014 5:47 pm
Forum: Automation, sensing and robotics
Topic: My Pi Car - It's a start!
Replies: 7
Views: 2027

My Pi Car - It's a start!

My Pi 'Car' on its Maiden Voyage. Unfortunately, the battery pack is insufficient to power both the Pi and the motors together (even though it's a 20Amp version), simply because the internal current sensing circuits of the battery are a bit too quick to restrict the power under brief current surge c...
by SavagePi
Tue May 06, 2014 8:37 pm
Forum: Automation, sensing and robotics
Topic: GPIO AutoCad Drawings
Replies: 3
Views: 1071

Re: GPIO AutoCad Drawings

Thanks for your help, Dougie.

I'll give that a go.
by SavagePi
Mon May 05, 2014 6:46 pm
Forum: Automation, sensing and robotics
Topic: ]Raspberry Pi + L298N H-Bridge + HC-SR04
Replies: 16
Views: 4213

Re: ]Raspberry Pi + L298N H-Bridge + HC-SR04

To me, this sounds like a simple matter power supply (current) lag. It's nothing to do with your motor controller, since this won't use any current until the motors actually start turning. The Pi needs enough surge current at startup to get it up and running (initially about 2Amps for 100mS). After ...
by SavagePi
Mon May 05, 2014 5:20 pm
Forum: Automation, sensing and robotics
Topic: GPIO AutoCad Drawings
Replies: 3
Views: 1071

Re: GPIO AutoCad Drawings

Anyone know how I could upload these file for everyone to view? :?
by SavagePi
Mon May 05, 2014 4:58 pm
Forum: Automation, sensing and robotics
Topic: ]Raspberry Pi + L298N H-Bridge + HC-SR04
Replies: 16
Views: 4213

Re: ]Raspberry Pi + L298N H-Bridge + HC-SR04

I'm using the very same L298N PCB. Here's a photo of my connections. I've removed the two links (En1 & En2) that normally enable the motors because I control those myself. Apart from the 6 control signals, you'll notice I've linked the 0V connection back to the Pi (this is the most essential connect...
by SavagePi
Mon May 05, 2014 3:46 pm
Forum: Automation, sensing and robotics
Topic: GPIO AutoCad Drawings
Replies: 3
Views: 1071

GPIO AutoCad Drawings

Hi all.

Not sure if this has been done before, but here are a couple of AutoCad drawings I've produced of the GPIO ports for both Rev1 and Rev2 boards.

Hope you find them useful.

Oh, sorry. The forum won't let me upload AutoCad 'dwg' files...

That's a shame! :(
by SavagePi
Fri Apr 04, 2014 5:52 pm
Forum: HATs and other add-ons
Topic: Gertboard Binary Display
Replies: 9
Views: 3702

Re: Gertboard Binary Display

Thank you for that information Gert van Loo.

That's very helpful ;)
by SavagePi
Tue Apr 01, 2014 8:18 pm
Forum: HATs and other add-ons
Topic: Gertboard Binary Display
Replies: 9
Views: 3702

Re: Gertboard Binary Display

Seems to be fine when copied and pasted into a text editor (even Python).

Hope it's useful to someone. I hope to share more programs in the future.

Thanks for all your help, panik.
by SavagePi
Tue Apr 01, 2014 6:51 pm
Forum: HATs and other add-ons
Topic: Gertboard Binary Display
Replies: 9
Views: 3702

Re: Gertboard Binary Display

Oh, that seems to work (sort of), apart from the limited viewing area kind of 'wraps' round the slightly long lines.

Thanks again, anyway :D
by SavagePi
Tue Apr 01, 2014 6:45 pm
Forum: HATs and other add-ons
Topic: Gertboard Binary Display
Replies: 9
Views: 3702

Re: Gertboard Binary Display

Thanks, panik. It's only 13Kb in size. Let me try something else then... # Gertboard Binary Display Program # This program is not written specifically for use with the Gertboard. # It will run perfectly OK on its own without connecting the RPi # to a Gertboard. If you wanted to, you could simply pat...
by SavagePi
Tue Apr 01, 2014 6:24 pm
Forum: HATs and other add-ons
Topic: Gertboard Binary Display
Replies: 9
Views: 3702

Re: Gertboard Binary Display

Thank you for your help, panik.

It's a pretty small program, so I'll try attaching it here first. But I'll try github too.

I have no idea if this will work, but here goes...

Oh, that doesn't seem to work. All I get is an error message saying 'The extension py is not allowed' :?
by SavagePi
Mon Mar 31, 2014 8:03 pm
Forum: HATs and other add-ons
Topic: Gertboard Binary Display
Replies: 9
Views: 3702

Gertboard Binary Display

Hello all. I'm totally new to all this, so please forgive me if I'm posting this in the wrong place. I bought a Raspberry Pi a couple of weeks ago with no idea what to do with it, but I did like the idea of trying to interface it to the 'real world' using the GPIO bus. Because of this, I decided to ...

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