PYPRCA - Python Programmable Calculator (computer)

DIY extremely simple pocket computer
Based on Raspberry Pi PICO+LCD+Buttons
Software in circuitpython

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Universal programmable device (computer) in pocket calculator style

Is prefect for learning programming and improve build/soldering skills.

Minimum parts make it ideal for learn to solder.

Some SMD parts are little harder to place for beginners but is possible
make semi populated boards ....

There is numerical block for better native enter numbers
and QWERTY block for write programs

Instead of searching 2nd,3th colorful symbols on chaotic ABCD keyboard you can type SIN,COS etc.... on well known QWERTY keyboard

Your formulas are send to REPL for execution

It is not only calculator, it is complete
standalone python computer with python firmware
and multiple selectable apps on startup.

Hardware features:

  • write and execute scripts on device
  • Optimized for circuitpython
  • some hardware GPIO Uart RX/TX or I2C SDA/SCL
  • SD card storage
  • beeper
  • interactive REPL
  • IPS 2.8" COLOR LCD
  • 49+1 tactile soft press keyboard in matrix 7x7
  • no 3D prints = durable PCB enclosure

Working software features:

  • Boot menu
  • Text Editor
  • Photoframe
  • Turtle graphics programming
  • Plot graph
  • play mp3
  • Retro computer emulation on separated firmwares
    already working emulation ZX128, ZX48, ZX81, C64, Atari800

TODO software features:

  • text/ebook viewer
  • longer text editor

STEM Learning:

What you can learn on this board?

  • assembly and soldering skills, you need just solder one Raspberry pi PICO module and 50 switches, display soldering need some skills but I selected one with low count wires
  • circuitpython or micropython
  • Arduino programming
  • C programming
  • QWERTY keyboard matrix reading
  • complex input/output HID processing read keyboard data,
  • create and display graphics
  • save and processing files
  • work with I2C sensors or process GPS data
  • RTC clock and alarms
  • With Raspberry Pi PICO W play with WiFi and bluetooth
  • Testing if is possible to use ESP32s3 on pico pinout compatible module
  • power management, sleep, wake by alarm, wake on receive

Production and marketing plans:

Hardware is very simple and easy to solder by hand, low active component count make it very attractive as learn to solder kit.
Plan is produce partially assembled kits with already soldered display, and DIY soldering switches.
Why TH tactile switches? because is very important to precise align with front cover plate and this can be little hard with hand.

Raspberry Pi PICO Advantages:

  • Unbrickable ROM bootloader
  • Drang&drop initial setup
  • Easy soldering
  • integrated power supply
  • onboard USB connector
  • testpoints for connect USB-A for as USB host
  • effective buck/boost powering
  • use Pico W with wireless without changes
  • Waveshare alternative Rp2040plus have lion charging + USB-C and double flash memory
  • Circuitpython with libraries for almost everything with tutorials and examples 

SWOT analysis


  • no competition with working pocket computer
  • compact encapsulated design
  • QWERTY keyboard, much user friendly than ABCD
  • officially supported Raspberry Pi PICO standard unmodified circuitpython
  • extremely simple just one easy solder module and buttons, cheap and low component count
  • low power consumption
  • native circuitpython apps, no monster OS behind
  • multiple apps on device and boot menu
  • GPIO for external sensors readings etc in school lab.
  • large 2.8"" all angles views IPS color graphics display 320x240


  • no community, no users
  • my programming knowledge is limited (I quickly learning)
  • display soldering need little more skills (semi-assembled kit may can help)


  • with good manufacturing plan it ca be very good education toy


  • I haven't caught competition in this segment, but if it appears with good marketing and a production plan may kill this simple idea
  • as everywhere, the main competition are touch screens and mobile phones

PYPRCA vs Numworsk

x-zip-compressed - 267.71 kB - 04/24/2023 at 21:50


View all 12 components

View all 5 project logs

  • 1
    Solder PICO module

    At first solder Raspberry PICO (or compatible) module, try apply power.

  • 2
    Install Circuitpython firmware

    Download Circuit python firmware directly from

    • connect to PC
    • hold BOOT button and shortly press RESET
    • free BOOT button
    • you can found new DISK drive on your computer
    • drag&drop downloaded file with uf2 extension
  • 3
    Solder LCD and related SMD parts

    Align LCD small corner columns to holes and solder FLEX cable

    Solder parts in BACKLIGHT section

View all 8 instructions

Enjoy this project?



fdufnews wrote 04/27/2023 at 13:02 point

You say that "the main competition are touch screens and mobile phones"

The shop you bought you display at has a variant of the display with the touchscreen option TFT HC28010-DCT it is a little more expensive but not too much. Didn't you consider using this one?

I think there is a mistake in the BOM DTS-64K seems to not exist.

There are DTS-644 or DTS-648 but these one have a square button not a round one.

7mm ones with a round button are DTS-63K

  Are you sure? yes | no

bobricius wrote 04/27/2023 at 13:10 point

yes but in this case it need create touch  "only" device, I not see sense to make hybrid touch and physical buttons. I watched on, currently I have no connector for this touch part and I have no touch driver, anyway I still love physical buttons devices, Also I want keep retro computer emulation. I will think about create touch only handheld. I am still confused with this touch and internet depended devices (smartphones phones) an I hear 10x per day (Do you have our app ????)

  Are you sure? yes | no

bobricius wrote 04/27/2023 at 13:13 point

yes, typo, you have true it is DTS-63K

  Are you sure? yes | no

alihamzagilitoo wrote 04/24/2023 at 23:05 point

Need help 😭 😭 

  Are you sure? yes | no

fdufnews wrote 04/27/2023 at 12:45 point

Maybe you can elaborate on this.

  Are you sure? yes | no

alihamzagilitoo wrote 05/03/2023 at 23:50 point

Plzzz hacke teenpatti because many money invest on this I am notal

  Are you sure? yes | no

fdufnews wrote 04/24/2023 at 22:26 point

Really interesting project.

Eager to see where it goes and maybe to make one.

  Are you sure? yes | no

John Hind wrote 04/19/2023 at 11:18 point

Adafruit have reverse-mount tactile switches which would allow this to be built on a single PCB (switch legends on the front of the board with switches soldered to the back).

  Are you sure? yes | no

bobricius wrote 04/19/2023 at 11:37 point

interesting idea, but I am afraid if there is enough space for wiring and also som doubts if hard press not cut switch from board and last if exist with 1N switch force.

  Are you sure? yes | no

John Hind wrote 04/19/2023 at 17:28 point

With standard PCB thickness, the switch actuator sinks flush with the PCB surface before bottoming out in the switch, so no stress on the solder pads. You can still have tracks on both sides so long as all the components fit on one side. Gives a cool techno look with tracks showing faintly under the switch legends! Some thought needed to make the display sit at the right level though.

  Are you sure? yes | no

M. Bindhammer wrote 04/17/2023 at 16:49 point

Does it support conjugate complex solutions for equations of the second to the fourth degree?

  Are you sure? yes | no

bobricius wrote 04/18/2023 at 06:13 point

no, currently it is only combination of text editor and internal python exec(), eval() functions + math library

  Are you sure? yes | no

zyndram wrote 04/13/2023 at 17:43 point

why python? why not ruby, mruby, haskell etc ;-)

( and please add network, for example irda )

  Are you sure? yes | no

John Hind wrote 04/19/2023 at 11:12 point

Does say it can use PICO-W which means WiFi and Bluetooth LE. Also I2C will allow use of the huge range of low-cost STEMMA and Qwiic breakouts for sensors (though a STEMMA-QT connector would be nice!)

  Are you sure? yes | no

zyndram wrote 05/14/2023 at 07:01 point

network must be interoperating, for any os, any medium, irda is very simple and working. Many BT version, zee etc is not flexible

  Are you sure? yes | no

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