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by mott555
Fri Mar 20, 2015 5:38 pm
Forum: Automation, sensing and robotics
Topic: Autonomous vehicle project
Replies: 12
Views: 4676

Re: Autonomous vehicle project

I can recommend something like this:

http://www.amazon.com/gp/product/B002DR3H5S

Image

They're about $20 and it's a tracked chassis with a motor and transmission but no electronics whatsoever. Great starter for R/C projects.
by mott555
Wed Mar 18, 2015 5:00 pm
Forum: General discussion
Topic: just one official armv7 OS Pl.
Replies: 20
Views: 2444

Re: just one official armv7 OS Pl.

I'm not too familiar with Raspbian versus standard Linux distributions, but is source available? If so, can't you just check out the kernel, rebuild it with ARMv7 support, and install it?
by mott555
Tue Mar 17, 2015 10:37 pm
Forum: Other projects
Topic: Feasibility - Raspberry Pi dashcam/mapper for dirt bike
Replies: 4
Views: 1973

Re: Feasibility - Raspberry Pi dashcam/mapper for dirt bike

First concrete question then...I want to programmatically capture video from the camera and add dynamic text. Are there any C/C++ libraries like this? Preferably something that generates an interrupt on each frame and gives me access to the bitmap to make modifications?
by mott555
Tue Mar 17, 2015 4:10 pm
Forum: Other projects
Topic: Feasibility - Raspberry Pi dashcam/mapper for dirt bike
Replies: 4
Views: 1973

Feasibility - Raspberry Pi dashcam/mapper for dirt bike

I just had an idea and wanted to post here to see if anyone has done anything similar, or if there are any existing software packages that would be useful. I'm a software engineer so I might be able to cobble together an application to help manage everything if needed, but I'm hoping I wouldn't have...
by mott555
Fri Mar 13, 2015 2:30 pm
Forum: General discussion
Topic: Power off ALL the way
Replies: 10
Views: 1549

Re: Power off ALL the way

Yep, that's the same battery I have. With a sample size of 2, I guess that's normal behavior then.
by mott555
Fri Mar 13, 2015 1:48 pm
Forum: General discussion
Topic: Power off ALL the way
Replies: 10
Views: 1549

Re: Power off ALL the way

Is it the Adafruit battery? Mine does the same thing, seems the battery will still leak a bit of voltage when off.
by mott555
Wed Mar 11, 2015 3:00 pm
Forum: Beginners
Topic: Can the Pi take 5800 mAh?
Replies: 7
Views: 805

Re: Can the Pi take 5800 mAh?

The mAh rating of the battery indicates how long the battery's charge will last when used. Higher values means the battery lasts longer. It has nothing to do with safety or the Pi's power requirements.
by mott555
Tue Mar 10, 2015 9:00 pm
Forum: Automation, sensing and robotics
Topic: Can i drive a small motor with the RP?
Replies: 7
Views: 1104

Re: Can i drive a small motor with the RP?

You can't directly run that motor off the Pi, but you could control it with an appropriate relay or transistor controlled by the Pi and an external 12V power supply of some kind.
by mott555
Fri Mar 06, 2015 2:43 pm
Forum: Beginners
Topic: Windows Executable on Pi 2
Replies: 3
Views: 646

Re: Windows Executable on Pi 2

Unless you cross-compiled for the Pi and ARMv7 on Windows, an executable built on Windows will not run on a Pi. As for the Windows 10 stuff, I think that's still well in the future but I'm not really in the know. I've also heard that Windows 10 for the Pi isn't going to be what everyone thinks it wi...
by mott555
Fri Mar 06, 2015 2:14 pm
Forum: Beginners
Topic: Correct way to run LED from GPIO
Replies: 8
Views: 1422

Re: Correct way to run LED from GPIO

If you want to read on the basics about LEDs, here's a good tutorial that cleared up a bunch of things for me. It talks about voltage drops and calculating resistor size.

https://learn.adafruit.com/all-about-leds
by mott555
Wed Mar 04, 2015 8:21 pm
Forum: General discussion
Topic: Where can I buy the Pi2 from that actually isn't incompetent
Replies: 3
Views: 607

Re: Where can I buy the Pi2 from that actually isn't incompe

I got mine from MCM. They told me it was on backorder until September, and then my Pi2 showed up in the mailbox a week later. :D
by mott555
Mon Mar 02, 2015 9:26 pm
Forum: General discussion
Topic: Does the Raspberry Pi work in a Vacuum?
Replies: 60
Views: 8728

Re: Does the Raspberry Pi work in a Vacuum?

I believe there are heatsink designs for better radiative cooling instead of convection, if in doubt something like that could be used to help with cooling in low-pressure environments.
by mott555
Mon Mar 02, 2015 4:17 pm
Forum: Troubleshooting
Topic: transposed keystrokes
Replies: 3
Views: 409

Re: transposed keystrokes

Raspbian defaults to UK layout. Use raspi-config to set your locale and keyboard layout.
by mott555
Fri Feb 27, 2015 10:36 pm
Forum: Automation, sensing and robotics
Topic: Protecting transistors from DC motor back-EMF
Replies: 15
Views: 2349

Re: Protecting transistors from DC motor back-EMF

The L9110 looks about perfect, 800 mA ought to be plenty because I think motor stall is unlikely given how light the chassis is, the tracks would just slip. The SN754410 seems to use 5V logic and I don't think I want to bother with logic-level converters.
by mott555
Thu Feb 26, 2015 10:31 pm
Forum: Automation, sensing and robotics
Topic: Protecting transistors from DC motor back-EMF
Replies: 15
Views: 2349

Re: Protecting transistors from DC motor back-EMF

The motors I'm using are only 3V so not appreciably different from the GPIO voltage, but they average around 300 mA and stall at 1 amp so I definitely don't want to drive them off the GPIOs. I did just stumble across some basic info about H-bridges but all the ones I saw online were for larger volta...
by mott555
Thu Feb 26, 2015 9:18 pm
Forum: Automation, sensing and robotics
Topic: Protecting transistors from DC motor back-EMF
Replies: 15
Views: 2349

Protecting transistors from DC motor back-EMF

I'm about to begin experimenting with driving small DC motors via transistors switched by the Pi's GPIO, including PWM for throttling. Most of my electronics knowledge is from analog audio amplifiers and not this kind of stuff, so I need clarification on something. I understand basic theory, but hav...
by mott555
Fri Feb 20, 2015 11:38 pm
Forum: Python
Topic: Pi 2 and GPIO - Not seeing voltage on pins
Replies: 5
Views: 3005

Re: Pi 2 and GPIO - Not seeing voltage on pins

Works now. I need to learn to count :mrgreen:
by mott555
Fri Feb 20, 2015 11:22 pm
Forum: Python
Topic: Pi 2 and GPIO - Not seeing voltage on pins
Replies: 5
Views: 3005

Re: Pi 2 and GPIO - Not seeing voltage on pins

Well mystery partially solved, I can't believe I didn't notice this! I was looking at 26-pin GPIO pinouts, but mine is a 40-pin! And given I was connecting to stuff at the high-pin end and counting down, I guarantee I was not plugged into the right pins!
by mott555
Fri Feb 20, 2015 7:23 pm
Forum: Beginners
Topic: Best board for Motors
Replies: 9
Views: 997

Re: Best board for Motors

I'm planning out a similar project, and my current plan is to use some transistors as relays/switches for the motors, and trigger the transistors using some GPIO outputs and play with PWM for throttling.
by mott555
Fri Feb 20, 2015 5:33 pm
Forum: Camera board
Topic: Multiple Cameras
Replies: 10
Views: 2493

Re: Multiple Cameras

Interesting, I stand corrected. That's what happens when I make unwarranted assumptions :D
by mott555
Fri Feb 20, 2015 5:18 pm
Forum: Camera board
Topic: Multiple Cameras
Replies: 10
Views: 2493

Re: Multiple Cameras

If you're into electronics, I doubt it would be too difficult to make a 2-way camera switch using a bank of switching transistors controlled by a single GPIO signal. That's assuming there are no additional protocol/driver or hotswap issues (I haven't done camera stuff yet on my Pi).
by mott555
Fri Feb 20, 2015 4:18 pm
Forum: Python
Topic: Pi 2 and GPIO - Not seeing voltage on pins
Replies: 5
Views: 3005

Re: Pi 2 and GPIO - Not seeing voltage on pins

Thanks, that looks useful. I'll try it tonight.

What do you mean by "The Pi 2 is hard float"?
by mott555
Fri Feb 20, 2015 3:57 pm
Forum: Python
Topic: Pi 2 and GPIO - Not seeing voltage on pins
Replies: 5
Views: 3005

Pi 2 and GPIO - Not seeing voltage on pins

So I just got the new Raspberry Pi 2 Model B (I'm still confused on the naming system but it's the new quad-core 1 GB version). Last night I was playing with the Python GPIO library and measuring pins using my multimeter since I don't have any LEDs or anything right now. In short, no matter what I d...
by mott555
Fri Feb 20, 2015 3:31 pm
Forum: General discussion
Topic: STICKY: Introduce yourself!
Replies: 3562
Views: 125965

Re: Introduce yourself!

Hello, I just joined after receiving my new Raspberry Pi 2. Been lurking for a few days here now, and I'm planning some kind of remote-controlled tracked vehicle over WiFi using my Pi. I'm a software engineer so it'll be interesting to get into hardware for once.

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