Raspberry Pi DAQ HAT Can Stack Eight High

By Eric Brown

In August, Measurement Computing Corp. (MCC) launched its MCC 118 voltage measurement DAQ HAT for the Raspberry Pi with eight ±10 V inputs and sample rates up to 100 kS/s. It has now released a promised MCC 152 voltage output and digital I/O HAT that can be stacked along with the MCC 118 and future MCC HATs in configurations of up to eight boards.

 
MCC 152 with Raspberry Pi (left) and stacked with other MCC 152 boards
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The $99 MCC 152 is equipped with two 12-bit, 0-5 V analog outputs with update rates up to 5 kS/s. There are also 8x bidirectional digital I/O lines with 3.3 V and 5 V support that can be “configured as input or output on a bit by bit basis,” says MCC. Each output bit can source 10 mA and sink 25 mA, and can be individually disabled.

Screw terminal connections are available for all I/O, and power is provided via the Raspberry Pi’s 40-pin GPIO connector. The 65 mm × 56.5 mm × 12mm HAT supports 0 to 55°C temperatures.

HAT configuration parameters are stored in an on-board EEPROM so you can set up the GPIO pins via the Pi when the HAT is connected. When stacking boards, onboard jumpers identify each board in the stack.



MCC 152 block diagram
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MCC provides an open-source MCC DAQ HAT Library in C/C++ and Python hosted on GitHub. The library includes console-based example programs with descriptions and lists of demonstrated functions. A MCC DAQ HAT Manager utility program offers an MCC 152 App to verify functionality. The utility requires the Raspbian desktop interface. API and hardware documentation are also provided.

Further information

The MCC 152 HAT is available for $99. More information may be found at the MCC 152 announcement and product page.

This article originally appeared on LinuxGizmos.com on January 10.

Measurement Computing | www.mccdaq.com

Raspberry Pi HAT Serves Up Robotics Control Smorgasbord

By Eric Brown

Adafruit has released a $35 robotics HAT add-on for any 40-pin Raspberry Pi board. The Adafruit Crickit (Creative Robotics & Interactive Construction Kit) HAT is designed for controlling motors, servos, or solenoids using Python 3. The board is limiting to powering 5V devices and requires a 5 V power supply.


Adafruit Crickit HAT with Pi and connected peripherals
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The Crickit HAT incorporates Adafruit’s “i2c-to-whatever” bridge firmware, called seesaw. With seesaw, “you only need to use two data pins to control the huge number of inputs and outputs on the Crickit,” explains Adafruit founder and MIT engineer Limor Fried in an announcement on the Raspberry Pi blog. “All those timers, PWMs, NeoPixels, sensors are offloaded to the co-processor. Stuff like managing the speed of motors via PWM is also done with the co-processor, so you’ll get smooth PWM outputs that don’t jitter when Linux gets busy with other stuff.”


 
Crickit HAT with and without Raspberry Pi
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The Crickit HAT uses a “bento box” approach to robotics, writes Fried. “Instead of having eight servo drivers, or four 10A motor controllers, or five stepper drivers, it has just a little bit of everything,” she adds.

Specifications listed for the Adafruit Crickit HAT include:

  • 4x analog or digital servo control, with precision 16-bit timers
  • 2x bi-directional brushed DC motor control, 1 Amp current-limited each, with 8-bit PWM speed control (or one stepper)
  • 4x high-current “Darlington” 500mA drive outputs with kick-back diode protection — for solenoids, relays, large LEDs, or one uni-polar stepper
  • 4x capacitive touch input sensors with alligator pads
  • 8x signal pins, which can be used as digital in/out or analog inputs
  • 1x NeoPixel driver with 5V level shifter connected to the seesaw chip (not the Pi), so you won’t be giving up pin 18. It can drive over 100 pixels.
  • 1x Class D, 4-8 ohm speaker, 3W-max audio amplifier connected to the I2S pins on the Pi for high-quality digital audio — even works on Zeros
  • 1x micro-USB to serial converter port for updating seesaw with the drag-n-drop bootloader, or plugging into a computer; it can also act as a USB converter for logging into the console and running command lines on the Pi.


 
Crickit HAT, front and back
(click images to enlarge)
 Further information

The Adafruit Crickit HAT is currently listed as “out of stock” at $34.95. More information may be found in Adafruit’s Crickit HAT announcement and product page.

This article originally appeared on LinuxGizmos.com on December 18..

Adafruit | www.adafruit.com