mohamed satti
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Appeal to the addition of ADC for the new version of RPI

Mon Feb 29, 2016 6:06 pm

Add a built-in ADC for rasperry pi is something necessary for most applications.
I think it's the most important thing ,Do you agree with the me ?
Let us try to convey our voice to the bosses, I think they're Lovely people and very close to us :) :)

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DougieLawson
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Re: Appeal to the addition of ADC for the new version of RPI

Mon Feb 29, 2016 11:51 pm

What's so hard about using an Arduino or an SPI/I2C ADC on your RPi? What you're asking for will never happen.
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jbeale
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Re: Appeal to the addition of ADC for the new version of RPI

Mon Feb 29, 2016 11:59 pm

You can get a (knockoff) "Arduino" Pro Mini for under $2.00 shipped. That gives you a complete microcontroller with deterministic timing, in addition to the analog in and PWM out. Easily connected to the RPi using UART (or even SPI or I2C if you want.)
http://www.ebay.com/itm/Hot-ATMEAG328-3 ... 2277014924

Also, since it is a separate module, it is easier to isolate it from the digital noise running around on the RPi mainboard due to the many high-frequency signals there.

Heater
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 12:21 am

I think it's a really bad idea.

The digital I/O we have can accept pretty much any analog converter out there. Baking in some crappy analogue circuitry does not seem like a good move.

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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 12:55 am

jbeale wrote:You can get a (knockoff) "Arduino" Pro Mini for under $2.00 shipped. That gives you a complete microcontroller with deterministic timing, in addition to the analog in and PWM out. Easily connected to the RPi using UART (or even SPI or I2C if you want.)
http://www.ebay.com/itm/Hot-ATMEAG328-3 ... 2277014924

Also, since it is a separate module, it is easier to isolate it from the digital noise running around on the RPi mainboard due to the many high-frequency signals there.
+1 I've found they really do compliment eachother.

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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 1:37 am

mohamed satti wrote:Add a built-in ADC for rasperry pi is something necessary for most applications.
Really! What brings you to that conclusion in light of 8 million Pis that lack that feature?

I'm not going to say that it will never happen, but I don't see it as a priority. As others have pointed out, there are other solutions. Besides the ones mentioned, there is the Gertduino.

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mikronauts
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 2:31 am

Do what I do.

Add an ADC (or more than one)
mohamed satti wrote:Add a built-in ADC for rasperry pi is something necessary for most applications.
I think it's the most important thing ,Do you agree with the me ?
Let us try to convey our voice to the bosses, I think they're Lovely people and very close to us :) :)
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

ejolson
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 3:40 am

While there are technical merits to the above explanations why no AD converter is built into the Pi, these responses, especially the ones about unicorns and ponies, are not particularly newbie friendly. These responses also fail to attempt an understanding at why the original poster thought built-in AD converters would be good.

A surprising number of Raspberry Pi owners, being children, are fully unemployed and after being gifted with a Pi have very little budget for add-on accessories. Even with the funds, such Pi owners likely have no credit card suitable for making even a small purchase online. On the other hand, having built-in hardware would create a standard which makes programming easier for everyone, adults included.

I have no idea about the programming background or age of the person who made the original post. What I do know is that this was his or her first post and that it was ridiculed. Maybe a link to a tutorial how to connect an AD converter to the Pi and use it would be more helpful.

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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 4:55 am

mohamed satti wrote:Add a built-in ADC for rasperry pi is something necessary for most applications.
I think it's the most important thing ,Do you agree with the me ?
I wouldn't expect that the pi should be all things to all people. There is a lot of room in the SBC space and you might look at the Beaglebone Green as an example closer to what you want. It is similarly priced to the pi3 but is not attempting to compete in the GHz or memory categories.

Others have suggested augmenting a pi with cheap Arduino clones bought off ebay. One advantage of that is problems that cause damage to boards might be limited to that cheap device and not propagate to your pi or other more expensive hardware. Maybe.

But feel free to argue for anything or any change you want to the pi boards but expect that some people around here really have their hearts set on a pony and you just won't be dissuading them of that no matter what you do.

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PeterO
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 8:04 am

The educational benefits of learning how to use to a device like an Arduino / Genuino to provide analogue inputs are much greater than having an on board ADC that just presents samples via "/dev/adc1".

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jamesh
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 6:01 pm

Worth noting that the next Pi is some years away, so any requests now will take some time to make it to final HW.
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Jednorozec
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 6:24 pm

jamesh wrote:Worth noting that the next Pi is some years away
Wasn't something like that said a year ago?
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 6:33 pm

Jednorozec wrote:
jamesh wrote:Worth noting that the next Pi is some years away
Wasn't something like that said a year ago?
Probably, but listen to some of Eben's recent interviews. This is probably the last Bcm283x chip. so anything in the future will need a new design of SoC, with associated problems with matching feature sets etc.
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mikronauts
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 6:34 pm

You can search Ebay for extremely cheap 8 bit PCF8591 I2C boards that are easy to connect to any Pi.

For better resolution, use an SPI MCP3008 / MCP3208, there are quite a few articles how to use one, including mine:

http://www.mikronauts.com/raspberry-pi/ ... and-howto/
mikronauts wrote:Do what I do.

Add an ADC (or more than one)
mohamed satti wrote:Add a built-in ADC for rasperry pi is something necessary for most applications.
I think it's the most important thing ,Do you agree with the me ?
Let us try to convey our voice to the bosses, I think they're Lovely people and very close to us :) :)
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

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mahjongg
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 6:43 pm

Its possible to "fake" an analog input, using a digital I/O pin on a PI, the resulting "analog input" has somewhat bad specifications. But it does work, and a demonstration of it was discussed in this forum. If I remember well, the demo simply used a LDR (light dependent resistor) and a 100nF capacitor to log ambient light data. The trick is to use the GPIO as output to discharge the capacitor, then measure how long it takes before the PI reads a '1' instead of a '0' from the cap charging to 3v3 via the resistor.

Similar techniques have been used with PIC controllers for decades, for example in PIC-BASIC modules, and is also used with parallax propeller chips.

The Apple ][ used a similar trick, using a 555 timer to create a joystick interface.
A trick the PC platform later "borrowed" for their analog joystick interface, so this method is ancient.

by the way the Broadcom silicon uses a process that is suitable only for digital logic, so its not obvious that you could add an analog input to it.

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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 6:48 pm

ejolson wrote:While there are technical merits to the above explanations why no AD converter is built into the Pi, these responses, especially the ones about unicorns and ponies, are not particularly newbie friendly.
And it's not just newbies it's not friendly to; it is verging on bullying in the way it is used to derail discussion and dismiss what a poster legitimately has to say.
ejolson wrote:These responses also fail to attempt an understanding at why the original poster thought built-in AD converters would be good.
It would be nice to have some ADC capability built in to the PI, some means to just wire a pot or two and use them with no extra components needed.

I would not say it's essential but there's plenty of aspects of a Pi which are not essential either.

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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 7:07 pm

I'm not seeing any unicorn or pony messages i this thread, why have they been brought up?
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Heater
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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 7:12 pm

Could have sworn I saw ponies and unicorns here earlier.

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Re: Appeal to the addition of ADC for the new version of RPI

Tue Mar 01, 2016 7:30 pm

Maybe an Arduino+Pi hybrid would be nice for some people, but adding even more stuff to the board will of course raise prices and it's unlikely to even fit.

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