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by Grumpy Mike
Tue Aug 21, 2012 4:33 pm
Forum: Python
Topic: WiringPython - WiringPi for Python
Replies: 205
Views: 72609

Re: WiringPython - WiringPi for Python

I have found that if after the:- git pull origin master I then go and make a copy of the file wiringSerial.c and call it serial.c I can then go through all the steps at http://blogs.foomatic.org/blink-away-the-tears/ Successfully, until the end, step 5 testing. gpio commands issued from the command ...
by Grumpy Mike
Tue Aug 21, 2012 2:31 pm
Forum: Python
Topic: What sort of WAV file for pygame?
Replies: 3
Views: 1672

What sort of WAV file for pygame?

I can play sounds from the wav files included in the Python games folder included with Raspbian but I can't play wav files I transfer over from my mac using an SD card. I noticed that the sample rate on the files I can play is 44.1KHz when I convert my files to that rate it still will not play. They...
by Grumpy Mike
Tue Aug 21, 2012 12:41 pm
Forum: Python
Topic: WiringPython - WiringPi for Python
Replies: 205
Views: 72609

Re: WiringPython - WiringPi for Python

If you: cd WiringPi/wiringPi git pull origin master You should get the latest files. I'm not familiar enough with git to know why on earth it doesn't get them when you do "git submodule update --init" When I do that and try the python setup.py build I get WiringPi/wiringPi/serial.c - no such file a...
by Grumpy Mike
Tue Aug 21, 2012 10:40 am
Forum: Python
Topic: Support for PWM that works?
Replies: 0
Views: 620

Support for PWM that works?

Does any one know an alternative to Python - WiringPi that will support PWM? Currently Python - WiringPi is broken see:- http://www.raspberrypi.org/phpBB3/viewtopic.php?f=32&t=10010&start=75 and I need to be able to use PWM as well as GPIO control. The actual wiringPi code from Gordon works and I ha...
by Grumpy Mike
Tue Aug 21, 2012 10:19 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Need help to get a Rotary Encoder working
Replies: 16
Views: 10273

Re: Need help to get a Rotary Encoder working

I beg your pardon, my previous remarks were regarding quadrature encoders, of which this isn't one. Sorry, misunderstood what you meant. However have you tried that sachem? It would not work with TTL up/Down counters because the flip flops inside the counters were not edge triggered master / slave ...
by Grumpy Mike
Mon Aug 20, 2012 10:17 pm
Forum: Python
Topic: [GPIO] Combining 2 different codes in to 1 program
Replies: 17
Views: 4189

Re: [GPIO] Combining 2 different codes in to 1 program

The purple ones are dedicated to SPI. No they are not. You are free to use them how you want BUT if you choose one of the alternative functions one of these alternative functions are SPI. All pins are GPIO pins first and specialised functions second. Note that the "Edit this post" link only appears...
by Grumpy Mike
Mon Aug 20, 2012 9:41 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Need help to get a Rotary Encoder working
Replies: 16
Views: 10273

Re: Need help to get a Rotary Encoder working

rurwin wrote:Then all you have to do is to read the value often enough that the software can work out which direction the count is going.
Yes that is ALL you have to do, but this is Linux so you can't.
by Grumpy Mike
Sun Aug 19, 2012 9:18 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Need help to get a Rotary Encoder working
Replies: 16
Views: 10273

Re: Need help to get a Rotary Encoder working

Found the chip that will do it for you.
The HCTL-2000, HCTL-2016, HCTL-2020 from Adgilent (Hewlett Packard)
by Grumpy Mike
Sun Aug 19, 2012 8:10 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADC audio via SPI
Replies: 11
Views: 16745

Re: ADC audio via SPI

Its not "Linux" that is the problem, its any multitasking OS no specifically designed to be hard real time, (Linux, but also Windows, and OS X. Yes it is Linux that is the problem. The fact that this problem exists on other operating systems is beside the point, we are a Raspberry Pi forum and it i...
by Grumpy Mike
Sun Aug 19, 2012 1:46 pm
Forum: Python
Topic: WiringPython - WiringPi for Python
Replies: 205
Views: 72609

Re: WiringPython - WiringPi for Python

I found this great introduction about installing WiringPi:- http://blogs.foomatic.org/blink-away-the-tears/ Sadly it doesn't work. First off because the setup.py build is asking for a file called wiringSerial.h and there isn't one. Sure there is a serial.h, so I substituted all the files in Gordon's...
by Grumpy Mike
Sat Aug 18, 2012 8:52 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: C GPIO library stops pin working.
Replies: 12
Views: 3881

Re: C GPIO library stops pin working.

RPI_GPIO_P1_01 throws a compiler error Sorry I didn't realise that that library uses stupid pin names. Yes looking at the source 00268 typedef enum 00269 { 00270 RPI_GPIO_P1_03 = 0, 00271 RPI_GPIO_P1_05 = 1, 00272 RPI_GPIO_P1_07 = 4, 00273 RPI_GPIO_P1_08 = 14, 00274 RPI_GPIO_P1_10 = 15, 00275 RPI_G...
by Grumpy Mike
Sat Aug 18, 2012 7:37 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: C GPIO library stops pin working.
Replies: 12
Views: 3881

Re: C GPIO library stops pin working.

Should this:-
#define PIN RPI_GPIO_P1_03
not be
#define PIN RPI_GPIO_P1_01
For GPIO 0
with a 10k pull-up to pin 1 (3V3).
No need for this as this pin has a 1K8 pull up resistor on the board for I2C
by Grumpy Mike
Sat Aug 18, 2012 6:19 pm
Forum: HATs and other add-ons
Topic: Is 3V3 GPIO HIGH voltage enough to fully turn on ULN2803a?
Replies: 7
Views: 5163

Re: Is 3V3 GPIO HIGH voltage enough to fully turn on ULN2803

The data sheet I have from an ULN2803a says 500mA TOTAL maximum. My data sheet says:- Each darlington features a peak load current rating of 600mA (500mA continuous) and can withstand at least 50V in the off state. So that is each one of the 8. However, thermal considerations restrain the total for...
by Grumpy Mike
Sat Aug 18, 2012 6:13 pm
Forum: HATs and other add-ons
Topic: Simple LED/Button input with GPIO
Replies: 18
Views: 8768

Re: Simple LED/Button input with GPIO

Does anybody know where I can buy the LEDs, resistors and buttons..........
http://www.oomlout.com/a/distr/
http://www.coolcomponents.co.uk/catalog ... -c-30.html
http://www.rapidonline.com/Electronic-Components
by Grumpy Mike
Sat Aug 18, 2012 5:35 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Interfacing with a board from different supply
Replies: 2
Views: 801

Re: Interfacing with a board from different supply

This is why you need to connect the grounds together:-
http://www.thebox.myzen.co.uk/Tutorial/ ... plies.html
by Grumpy Mike
Sat Aug 18, 2012 5:27 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Need help to get a Rotary Encoder working
Replies: 16
Views: 10273

Re: Need help to get a Rotary Encoder working

You can add hardware to count the signals and then read the counter with parallel GPIOs, I did a project years ago, the relevant part is here:- http://www.thebox.myzen.co.uk/Workshop/Rotary_Max.html If you do this note that the pin out of the 74LS75 can change as there are different versions of it s...
by Grumpy Mike
Sat Aug 18, 2012 5:19 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Help interfacing 13.8Vdc to GPIO
Replies: 6
Views: 1583

Re: Help interfacing 13.8Vdc to GPIO

The main question is, what SHOULD I be seeing here? A very small voltage because the 13.8V turns on the transistor so it conducts electricity and so reduces the voltage between the emitter and collector to effectively zero. So it looks like it is working fine. When you remove the 13.8V from the bas...
by Grumpy Mike
Sat Aug 18, 2012 4:21 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: ADC audio via SPI
Replies: 11
Views: 16745

Re: ADC audio via SPI

The problem with a simple A/D converter digitising audio is that Linux steals time from you. You have little control over when this happens so your audio will contain clicks, or discontinuities in the data stream. DAC's are really not suitable for audio, you really need a codec of some kind! Rubbish...
by Grumpy Mike
Sat Aug 18, 2012 4:14 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Need help to get a Rotary Encoder working
Replies: 16
Views: 10273

Re: Need help to get a Rotary Encoder working

The problem with a rotary encoder is that you have to be looking at it when it makes the transitions or at least between the transitions. It depends on your application. Can you afford to miss any pulses? What speed will these be produced at? The main problem is that Linux will not allow you to poll...
by Grumpy Mike
Thu Aug 16, 2012 7:37 pm
Forum: Off topic discussion
Topic: Button Interface
Replies: 1
Views: 433

Re: Button Interface

Page 7 of the July (issue 3) of MagPi
http://www.themagpi.com/
It's free.
by Grumpy Mike
Thu Aug 16, 2012 7:12 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: USB to parallel printer port on the PI??
Replies: 8
Views: 7341

Re: USB to parallel printer port on the PI??

using FPC
What is this? It goes without saying as I don't know what it is I haven't knowingly got any examples of it.
by Grumpy Mike
Wed Aug 15, 2012 9:38 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: GPIO max current
Replies: 34
Views: 108091

Re: GPIO max current

Have you read this?
http://www.thebox.myzen.co.uk/Raspberry ... tputs.html
It tries to explain what it means.

I was just going to post it but Gert intervened before the post was finished. It was too big to post anyway.
by Grumpy Mike
Wed Aug 15, 2012 9:26 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Help interfacing 13.8Vdc to GPIO
Replies: 6
Views: 1583

Re: Help interfacing 13.8Vdc to GPIO

Just look for 1/4 W axial resistors as cheap as you can find. This link has them sorted by price:- http://uk.farnell.com/jsp/search/browse.jsp?N=2031+203968+110019895+110062552+110323891+110324042&Ns=P_PRICE_FARNELL_UK|0&Ntk=gensearch&Ntt=resistors&Ntx=mode+matchallpartial&locale=en_UK&appliedparame...
by Grumpy Mike
Wed Aug 15, 2012 6:53 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: 74HC595 Shift Register IC Vcc
Replies: 16
Views: 12558

Re: 74HC595 Shift Register IC Vcc

I'm using the Aruduio Tutorial on Shift Out as the basis of my build.
In which case remember that the 1uF capacitor on the latch pin is an error. Connect a 1uF to 0.1uF across the supply pins of the 595.
by Grumpy Mike
Wed Aug 15, 2012 6:29 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: USB to parallel printer port on the PI??
Replies: 8
Views: 7341

Re: USB to parallel printer port on the PI??

does it have some kind of communication layer that allows printers to print but not necessarily to access the individual I/O pins?? The device itself has not. Any limitations will be caused by the USB driver, if any, you can get hold of for Linux. I have one myself I got from Maplins a few years ag...

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