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Read Analog value in Raspberry Pi 2

Former Member — Fri, 24 Jun 2016 09:04:37 GMT

I have a raspberry pi 2 how can i read the analog value ?what will be the python code

RE: Read Analog value in Raspberry Pi 2

oksbwn — Sat, 25 Jun 2016 09:50:11 GMT

Yes you can use MCP3208 and the JAVA PI4J Library has full support for that.

RE: Read Analog value in Raspberry Pi 2

RParkerE — Fri, 24 Jun 2016 14:08:10 GMT

The Raspberry Pi's GPIO only accepts digital input. To read an analog signal you will need to purchase an Analog to Digital Converter (ADC), something like a MCP3008 would work.

RE: Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Wed, 24 Dec 2014 10:00:52 GMT

I am trying to add an RTC to my Pi/Wolfson Audio card combo and was wondering whether your solution is working well? Also, do you have any more photos/instructions on what you did exactly. I am a newbie to the Pi and electronics in general but am looking to get my pi/wolfson unit to record sound to a particular schedule - hence my needing an RTC. My unit won't have access to wifi so I need to add a clock to it. I might end up using a B+ and the Cirrus Logic Audio Card but I think the problem will be similar as I think that card also takes up all of the GPIO pins.

Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Sun, 04 May 2014 17:51:00 GMT

Raspberry Pi provides GPIO on P1 and P5 connectors. Both these connectors are occupied by Wolfson Sound card.. Two on these GPIO are available on Wolfson card. In our project we need 5 GPIO. Hence the two questions:

1. Of the GPIOs on P1 and P5 which ones are NOT used by the Wolfson sound card?

2. What is the best way to phyiscally accesses these GPIO.

We would not be able to use the Wolfson sound card if we do not get access to in total 5 GPIO pins. Please assist.

RE: Access to 5 GPIO pins with Wolfson Sound Card

Marki555 — Sun, 17 Aug 2014 17:13:17 GMT

Also GPIO3 on expansion header is available (connected to GPIO3 of WM5102 and to P1 pin 22 of RPi). I guess it can be used, else they wouldn't expose it on the expansion header.

The P1 i2c is used to control the WM8804 SPDIF chip, but I see no issue in connecting another devices to the bus as suggested.

RE: All the Raspberry pi GPIO pins are occupied by Wolfson audio card... :( need access to GPIO :(

Former Member — Fri, 25 Jul 2014 10:14:22 GMT

Dominic Amann wrote:

From the schematic, I take it that the audio card uses the i2c pins (1.3 and 1.5) on the header - can I still connect to these pins for another i2c device?

Yes, you can. I2C bus is designed for multiple devices.

RE: All the Raspberry pi GPIO pins are occupied by Wolfson audio card... :( need access to GPIO :(

dimonic — Thu, 24 Jul 2014 20:49:06 GMT

From the schematic, I take it that the audio card uses the i2c pins (1.3 and 1.5) on the header - can I still connect to these pins for another i2c device?

RE: Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Mon, 30 Jun 2014 12:37:37 GMT

Only two GPIO are available on header pins on the Wolfson card - UART0_TXD (GPIO14) and UART0_RXD (GPIO15).

The Pi I2C does not route to the expansion header on the Wolfson card. If you want to connect a port expander I suggest soldering a 2 x 3 pin header to the top of the wolfson board at the Pin 1 end to make the I2C pins available to expansion boards and jumpers.

I have soldered such a header and attached a RTC module to it. You could attach a gpio expander by jumper wires. Here is a photo showing the soldered header pins and RTC module. The flying leads from the RTC board connect to a GPIO expander.

RE: Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Mon, 30 Jun 2014 11:14:33 GMT

I am also interested in using some of the GPIO while using the Wolfson audio card. I have the card working, streaming audio from a server share over the network and it sounds very good. There is an "expansion header" shown on the photograph of the Wolfson audio card in the user documentation. However, there is no pin out for the "expansion header". There is, in the annexe, a table titled "e. Feature header signal assignment" that details the pin out for a 16 pin header. By a process of elimination (There is only one 16 pin header on the board!) I think the "Expansion header" and "Feature Header" are the same thing. If this is right, you have access to two GPIO connections and a range of audio connectors on this header. Just a shame the documentation is not more consistent.

Anyone from Element 14 or Wolfson like to confirm that the Feature and expansion headers are the same thing and that he pin out is correct?

RE: All the Raspberry pi GPIO pins are occupied by Wolfson audio card... :( need access to GPIO :(

Former Member — Sun, 15 Jun 2014 14:34:19 GMT

The Wolfson Sound Card doesn't fit on the Banana Pi.

Ragnar

All the Raspberry pi GPIO pins are occupied by Wolfson audio card... :( need access to GPIO :(

indiant3chi3 — Tue, 15 Apr 2014 18:14:15 GMT

H3ll0 all !!

Is there any other way to access the Raspberry pi GPIO pins ..?? Since all the pins are occupied by wolfson card need help [View:/resized-image/__size/16x16/__key/communityserver-discussions-components-files/93/contentimage_5F00_2.png:16:16] plzzz...

RE: All the Raspberry pi GPIO pins are occupied by Wolfson audio card... :( need access to GPIO :(

Former Member — Sun, 15 Jun 2014 14:17:37 GMT

actually,I suggest you can try about another board same function as Raspberry PI named BANANA PI.Now it's popular~I heard from my friend about that,if you need more information,please contact me~miyali@sinovoip.com.cn

RE: Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Wed, 04 Jun 2014 07:40:40 GMT

I suggest you use a i2c port expander or USB I/O device.

I have a real-time clock module connected to header pins I have soldered onto the Wolfson to connect the i2c. It works and seems to cause no problems with audio.

By soldering two full rows of header pins to the top of the Wolfson you get a stacking connection to support a standard Pi expansion board. As long as any board you add doesn't use GPIO other than the i2c, and doesn't conflict with an i2c address on the Wolfson, it should work.

IMPORTANT check carefully that any card you attach does not use other GPIO lines or you may damage something.

Insert the pin headers into the female connector of your daughter card to maintain proper alignment. Position the pins over the pins on the Wolfson and carefully solder the pins at each end of each header strip. Solder the pins along the edge then remove the daughter card to access the pins on the inner strip. Be careful not to short the pins solder. Be careful when plugging or removing a daughter card.

You could use the HobyTronics expander in this scheme.

RE: Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Mon, 19 May 2014 16:37:10 GMT

Thanks for your reply. Here are use of 5 GPIO pins:

1. Panic Buttion GPI

2. Buzzer GPO

3. Fan control GPO

4. Shutdown - GPI

5. Shutdown complete - GPO

RE: Access to 5 GPIO pins with Wolfson Sound Card

fvan — Tue, 06 May 2014 11:56:42 GMT

What is it exactly you need to do with the 5 GPIO ?

As pigraham suggested, there are different ways of getting around the Wolfson occupying all GPIO.

In a project I'm working on, I'm doing the following:

* Use the Serial Tx/Rx pins which are made available on the Wolfson card for serial communication with an ATtiny

* Use an Arduino Micro/Leonardo connected via USB as Keyboard emulator in order to pass buttons being pressed to the Pi

Hope this helps

Frederick

RE: Access to 5 GPIO pins with Wolfson Sound Card

Former Member — Tue, 06 May 2014 09:49:35 GMT

I think your options are:

1. Wire an I2C interfaced GPIO expander to the Pi I2C pins in parallel with the Wolfson card. Maybe PCF8575, or MCP23017.

2. Use a microcontroller on Pi I2C or serial port to handle your I/O. Serial port is accessible at pins on the WAC.

3. Use a USB I/O device

4. Use a different audio device that doesn't monopolise the GPIO.

Useful links:

MCP23017-E/SP - MICROCHIP - IC, IO EXPANDER, 16BIT, I2C, 28DIP | Farnell UK

Raspberry Pi MCP23017 Port Expander Board Kit | RPI-PORTEXP | HobbyTronics

It's a shame Wolfson didn't use something like this to implement the board control functions, leaving the standard GPIO free.

RE: Did any one tried playing videos on VlC media player ???

saurocksall — Wed, 30 Apr 2014 07:18:56 GMT

Its a Nokia charger 5 Volts , 1300 ma....

Did any one tried playing videos on VlC media player ???

saurocksall — Sat, 26 Apr 2014 18:40:56 GMT

Hi fellow contestants,

Have any one of you tried playing video files VLC media player, I tried the video was very laggy, it was only a 360p video,

the other thing is that Wolfson Audio card doesn't work smoothly, and raspberry pi hangs form time to time, i did some research and found that Wolfson Audio card requires a class 6 or higher memory card, the one provided to us was a class 4 card.

And is there any way to get the Wolfson audio card working with RaspBMC, Because playing media content on Raspbian is really not that easy as very less time is left and there is almost no support, documentation for the Wolfson Audio card so it took me time to find out that it requires a class 6 or higher card, what type of card are you guys using ??

There Is also a over heating problem with my raspberry pi are you also facing something like this ??

RE: Did any one tried playing videos on VlC media player ???

shabaz — Tue, 29 Apr 2014 19:25:55 GMT

Not sure if those are h/w accelerated but omxplayer definitely is.

I still suspect PSU or the USB cable connected to the PSU issues, was this a power supply with USB cable from Element14, or your own? If it is your own, is it from a smartphone or from a non-smartphone? Older PSUs for smaller phones will not have the power to support the combination possibly.

RE: Did any one tried playing videos on VlC media player ???

rohitrangwani — Tue, 29 Apr 2014 19:14:04 GMT

Hi Saurabh,

Yes,my Pi with Wolfson card also freezes ,sometimes display to rca connected screen goes out after some time,usb devices stops working leaving only the option to go for hard reboot.

But sometimes it works fine.

You can use mpg player (mpg123) or mplayer.Both of these do play videos.

RE: Did any one tried playing videos on VlC media player ???

saurocksall — Mon, 28 Apr 2014 17:48:41 GMT

Hi Rohit,

Are you also facing over heating issue when Wolfson card is attached with raspberry pi ??

Is your Pi also hanging and freezing from time to time ??

and what player are you using and is it lag free ?? and does it plays videos ??

RE: Did any one tried playing videos on VlC media player ???

rohitrangwani — Mon, 28 Apr 2014 17:02:44 GMT

I am facing some similar problems with wolfson card.I dont think its compulsory to use class 6 or higher sd card.(this is only required for high quality audio).

But the problem is the instability of Raspberry Pi as you mentioned.

And as far as Vlc is concerned you can opt for other players as vlc is not hardware accelerated.

Where and How to submit my Rocking Raspberry pi.. project??

indiant3chi3 — Mon, 28 Apr 2014 16:41:15 GMT

Hi all

I am one of the finalist for the Rocking raspberry pi challenge (INDIA). The dead line for the project submission is 2nd May 2014. Where and how the project to be submitted?? is there any other additional details to be provided with my project ?? Please I need clear info....

Thanks

-- Srinivasan Kanni udaiyar.

RE: Where and How to submit my Rocking Raspberry pi.. project??

babusingh9211 — Mon, 28 Apr 2014 16:55:03 GMT

Hi shrinivasan,

Well I am also the finalist, also I don't know where the project is submitted.

In the terms and condition they say to blog the project.

So I am doing that.

--Sumit Rai