A/D Converters

[jlamperez]

A/D Converters

Raspberry Pi has not analog inputs. This are important for the design of the new SmartServo prototype.

The prototype we have built until now has 4(5) ADC to measure: Position, Current, Battery and Position (BEMFV).

I have been searching for ADC modules for the raspberry pi and I have found this ones:

• MCP3004/3008 : a module with 4 or 8 ADC channel with a precission of 10 bits and SPI interface.It can be bought from adafruit.
• ADS1113, ADS1114, and ADS1115 from Texas Instruments. A 16 bits precission ADC for 4 channel. The interface in this case is I2C and the disadvantage is that there are only QFN-10 package or an MSOP-10 package, a breakout board will be necessary. It can be bought from Texas Instrument Store.
• ADS1015 12-Bit ADC - 4 Channel with Programmable Gain Amplifier

Someone knows other types before order ones?

Also I open this issue to discuss about the precision of the ADC. Now the microcontroller inside has an ADC of 10 bits but since it will be outside in the new prototype it is worthy to increase this value to 16 to be more accurate? It will be better a SPI interface or I2C?

[vmayoral]

We commonly use the ADS1115. I'd recommend going for this one.

We can easily fetch a breakout from https://www.adafruit.com/products/1085. What else is needed?

[jlamperez]

For now with a pair of this ADS1115 I think it is enough because the control of the H-bridge I think it can be done using the specific GPIOs. If we have to change some components in the H-bridge because the GPIOs are of 3V3 I will let you know

[vmayoral]

Have a look at the TXS010x - x=number of channels