Raspberry Pi Forums

mayannaise

Power = Voltage x Current Assuming 100% efficiency (power in = power out) Therefore: Vin x Iin = Vout x Iout 3.7V x 1.5A = 5V x Iout Iout = 5.55/5 Iout = 1.11A This means that the amount of current that the PI can draw from the lipo (through the DC/DC) would be 1.11A. The official PI figure is 2.5A,...

mayannaise

What is your motor driver H/W setup? I ran your code quickly and it seems to be outputting the expected bit pattern, so I guess that it might be more of a hardware than software issue. Something to try: It could be the motor missing steps, so try slowing down the speed between the pulses (self.waitT...

mayannaise

-rst- wrote:You need to keep the script running using an (near-)infinite loop - something like:

Using a loop seems to defy the point of using an interrupt in the first place - might as well just poll the i/p. Surely there is a better way to use the interrupt, or is this one of the limitations of Python?

mayannaise

idunnoman wrote:Thanks guys, I will check out ptgame

That would be pygame

Have a look at http://raspberry.io/projects/view/readi ... om-python/ for reading GPIO buttons in python.

mayannaise

A man walked into a bar with a Raspberry PI on his head. He ordered a pint.
As he walked to a table, the PI fell to the floor.

The barman chuckled, "A SoC off the ol' block!"

mayannaise

Hello and welcome idunnoman, I hope I can help a little: I want the program to start with a single image with 4 circles on it pygame is a set of python modules used for writing graphical games. It actually comes pre-installed with the PI's default OS. There are some good tutorials at http://pygame.o...

mayannaise

A couple of things to try: Test if the DNS is working correctly. This can be achieved by pinging your new domain name and seeing if it is the same as your public IP address ( http://www.whatsmyip.org/ ). If the DNS is working, check your firewall settings on your broadband/internet router/modem. You...

mayannaise

I've seen much discussion about the possibility to make a PI-powered 3D printer, but I've never actually seen a genuine one. All of the ones I've seen so far simply use the PI as an interface to push GCODE commands to the printer (simply eliminating the need to have a PC hooked up to the printer for...

mayannaise

I use a 64GB microSD card in an SD adaptor for one of my PIs, and as can be imagined, these have to be fairly rugged to mount the microSD card-holding mechanism etc. I've had no problems with this and I find it much cheaper to buy a 64GB microSD than a 64GB SD ;) (I don't know why, but I don't mind).

mayannaise

It's quite a mystery! I would only expect the cause of a PI's death to be peripherals, corrupt SD or overheating (from overclocking etc etc) - but neither of these are applicable in your situation. Normally I would start to check things like the polyfuse and the voltage across the testpoints TP1 and...

mayannaise

What sort of atmosphere are you running it in? Enclosed in a box? With heatsink? Still air? Cooling fan? Damp/moist/humid? On a windowsill in direct sunlight? How heavy is the server you are running on it? CPU intensive? From where did you purchase your PI? A reputable supplier? There is a chance t...

mayannaise

Hello, and welcome to the world of the Raspberry PI and the forums. You will find a whole host of people (better than myself) on here which are more than eager to help you out of any difficulty. So, to start with, the most common languages hich are used to program the GPIOs are Python, Scratch, Bash...

mayannaise

I'm glad your PI survived

I accidentally put +12v on a GPIO input pin a while back. Needless to say that GPIO does not work anymore.

mayannaise

Never been to a Jam yet, but they look like fantastic events. I was in a secondary school a few weeks back, giving some talks on the Raspberry PI and showing off the amazing features of this SBC with some live demos and hands-on activities. It was great to see the reception that it got considering v...

mayannaise

My PL2303 arrived yesterday. I tried it out this morning and it works a treat.

Thankyou everyone for your help - my PI has been resurrected!

mayannaise

evilkitty wrote:I have it using the relay now

... and to think of all that chocolate we wasted

mayannaise

The pros have been discussing quantum physics behind the scenes and I think it is now agreed that Burngate's latter suggestion is the best in this given scenario. Obviously, a lone BJT or logic-level FET would be a more straight forward alternative as has been suggested. Filling in Burngate's schema...

mayannaise

I have had the same problem, but it only exists if you keep logging in and out all the time. If you select the option to stay logged in, then there will be no issue - it worked for me. But not if you are using a shared computer, of course!

mayannaise

Just download a recent Ubuntu (or practically any other Linux Distro - they pretty much all work as Live CDs) burn it to a CD and boot from it, hey presto a Linux PC. Or, better than that, boot from a flash drive (and don't "waste" a CD). I use Universal USB Installer which is very simple and the O...

mayannaise

In this case, there's actually no current flowing through the emitter, because the FET gate is an open-circuit for DC Cheers, I forgot that the FET is o/c and therefore emitter is floating - I understand now. If you want to know why it's that voltage you'll have to learn about silicon band-gaps, an...

mayannaise

my suggestion is this: get an n-channel MOSFET that has Rdson (that is the ON-resistance) specified at 2.5V. so it will for sure turn ON whan 3.3V is applied to the gate. That is what my original suggestion in my first post was. I suggested the IR L 540N (logic level version of IR F 540), which I h...

mayannaise

Your grounds will be fine.

Have you measured the voltage at the transistor's collector? Can you post a close-up photo of the breadboard so we can ensure the transistor etc. has been wired up correctly?

mayannaise

you mean the pi ground and the PSU ground? This is my PSU - https://www.adafruit.com/products/501 it only has 5v at 5v this fan moves plenty of air, i don't need it loud and noisy, it is more than surfactant overkill for a pi using the same PSU for the Pi and the fan How are you connecting the fan ...

mayannaise

maybe i should point out my 5v power is coming strait from my PSU not the PI's 5v pins In that case I should point out that you probably need to connect both grounds together. Have you done as Tarcas suggested? Also, why are you running the fan at 5v? It might work better at 12v if your PSU can sup...

mayannaise

Thanks for the help.

I'll be running Fedora 16, so I'll give the PL2303 a go.

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