I'm looking at options for ADC on the Rasbperry Pi. I'm wondering what is possible so far. Of course easy and cheap is good.
The ADS1113, ADS1114, and ADS1115 are precision analog-to-digital converters (ADCs) with 16 bits of resolution offered in an ultra-small, leadless QFN-10 package or an MSOP-10 package. The ADS1113/4/5 are designed with precision, power, and ease of implementation in mind. The ADS1113/4/5 feature an onboard reference and oscillator. Data are transferred via an I²C-compatible serial interface; four I²C slave addresses can be selected. The ADS1113/4/5 operate from a single power supply ranging from 2.0V to 5.5V.
First you need to make sure the I²C modules are loaded. Next connect the ADS1115 as shown below. There are 4 different addresses possible depending which pin ADDR is connected to. This means you can connect a total of 16 channels to a single I²C bus.
GND=0x48, VDD=0x49, SDA=0x4A, SCL=0X4B
You can see the result of the last conversion like this
# i2cget -y 0 0x49 0 w 0x0000
The default of 0x0000 is returned here since no conversions have been performed yet. Now lets take a look at the config register
# i2cget -y 0 0x49 1 w 0x8385
The LSB is first, so this is equivalent to
I'd like to do a single-ended conversion on AIN0, so I need to write bits[14:12] as
# i2cset -y 0 0x49 1 0xC385 w # i2cget -y 0 0x49 0 w 0xa30b
The LSB is first, so this is equal to 2979 decimal
Well as long as your desired use doesn't demand super high bitrates or resolution you could probably just use an Arduino. Arduinos are nice because they have a huge community for support, they've been around for a while, and communication over USB no GPIO!
Here's a link for to Simon Monk's blog post with instructions on how he communicates to the Arduino from a Raspberry Pi with python.
Similar to using an Arduino but how about a PICAXE device, connected to the RPi UART? This would be smaller and much cheaper. To me, Arduino seems over the top depending on your actual needs.
In a month or two, (due to shipping to Africa) I'll be getting a I2C PCF8591 board that has wiringpi support WiringPi site and the board uses 3.3v (typically) I got the WaveShare version on amazon Amazon link From what I've read, the PCF8591 is pretty nice but until I actually have the board in front of me, I can't say if it's good or not
An interesting solution here: http://www.theremino.com/en/blog/standalone-applications/#raspberry
Not only ADC but any type of configurable Input Output for the Raspberry Pi.