DIY Electronic Eyes Mask Pair of Cat-eye Spectacles - Adafruit MONSTER M4SK

 A fun microcontroller platform for creating costumes or decorations is the Adafruit MONSTER M4SK. The form of the PCB is similar to a pair of cat-eye spectacles, except instead of lenses, it has two 240240 TFT displays. On those two monitors, the default application on the board sets animated eyeballs that gaze about randomly. With a little capacitive touch-sensor nose on the bridge, the cat motif is continued by the silkscreening on the board. Cross your eyes when you touch your nose. One may envision employing these out of the box in a Halloween-themed application.

DIY Electronic Eyes Mask Pair of Cat-eye Spectacles - Adafruit MONSTER M4SK

When we turn around and look at the back of the board, we discover a lot more than we anticipated. A Cortex M4-based microcontroller from Atmel running at 120 MHz controls the screens. For storing graphics, the microcontroller has 8MB of QSPI flash memory available. In addition to the touch sensor at the front, there are other sensors, including a three-axis accelerometer on the right "lens" of the PCB. A light sensor that faces the front is visible on the left through a hole on the PCB. Three tactile switches are located along the top edge. A reset switch and an on/off switch are also present. There is a USB micro-B port for programming.


There are several extension ports visible around the board's edge. A 2-pin speaker connection and headphone jack come first. The board's tiny class-D amplifier can power headphones or a 1-watt, 8-ohm speaker. JST connections are located on the board's lateral borders. The microcontroller's I2C bus is connected to the four-pin port. The two three-pin ports link to digital IO pins that provide analog input and PWM output. These ports are all compatible with Grove and STEMMA (not STEMMA QT). LiPoly batteries include a two-pin battery connector, and the onboard charge controller allows you to charge them through electricity from the USB port. There is a tiny connection for a PDM microphone on the bottom edge.

The rear of the board has two nine-pin connections, one on each lens and facing the other across the bridge. The user may split the two sections so they can be put farther apart thanks to tiny holes between each lens and the bridge. The 9-pin JST cable, which can be obtained from Adafruit along with the board, is then used to link the two lenses together. By placing a second microprocessor on the lens opposite the one housing the primary microcontroller, Adafruit was able to link the two sides of the board using only nine pins. Seesaw, a framework that this second microcontroller runs, enables it to function as an I2C port expander for the first microcontroller.

Adafruit MONSTER M4SK - DIY Electronic Eyes Mask Features:

  • ATSAMD51G19 Cortex M4 microcontroller running at 120MHz with 512KB Flash, 192KB RAM
  • 8 MB QSPI flash for storing graphics and sound effects
  • Two 240x240 IPS TFT displays each on their own SPI bus
  • Beautiful silkscreen with a boop-able nose that is a capacitive touchpad
  • Lipoly battery charge circuit for portable use
  • Stereo headphone jack out, for sound effects via an amplifier
  • Mono speaker driver for smaller 8-ohm 1W speakers
  • One 4-pin STEMMA JST connector for I2C connection (also Grove compatible)
  • Two 3-pin STEMMA JST connectors with digital/analogue/PWM for servos, sensors, etc
  • One 4-pin JST SH port for connecting an optional PDM microphone
  • Backlight controls
  • Three tactile buttons
  • Light sensor
  • On/Off Switch and reset button

 The MONSTER M4SK has good documentation. Because the UF2 bootloader is already present on the board, firmware may be placed directly onto the device in your operating system. This is advantageous because the UF2 bootloader upgrade is the first step in Adafruit's guide. Double-click the reset button after USBly connecting the board to a computer. As a USB mass storage device, the board will mount. The most recent UF2 bootloader may then be dropped into place after being obtained from the MONSTER M4SK's CircuitPython website.

At this stage, you have the option of using the Arduino IDE or CircuitPython to program the board. Drag and drop the CircuitPython UF2 file onto the USB mass storage device, exactly as you did with the upgraded UF2 firmware, to get CircuitPython up and running. You should go to the section of the walkthrough that explains how to rebuild the default software from the source code in order to program the board in the Arduino IDE.

Adafruit says that they were unable to get the example code to run in Circuit Python since the language just wasn't fast enough. It is true that the first thing to do after installing the Arduino IDE's support for the board and a number of libraries is to set the board's overclock to 180MHz and change the compilation parameters to quicker (-O3) optimization. The example code seems to strain the board's capabilities. The faults that will happen if you push the board even farther are described on a page for debugging board issues.

DIY Electronic Eyes Mask Pair of Cat-eye Spectacles - Adafruit MONSTER M4SK

When getting the MONSTER M4SK from Adafruit, there are a lot of accessories that you need to take into account. The aforementioned 9-pin JST cable may be used to separate and remove each eye. They also sell a LiPoly battery and a 1W speaker that plug into the respective onboard connections. Additionally, there are glass and plastic convex lenses that will enlarge each "eye" shown on the displays, but keep in mind that you will need to create a holder for the lenses that work with your finished product. On the Learn parts of the Adafruit website, you may find examples of projects, some of which incorporate the lenses.

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