Mod: Replacement Raduino

UBITX.NET RECOMMENDS YOU ONLY CONSIDER REplacing your Raduino if it is damaged or if you require a processor upgrade or more i/o Ports

Why replace your raduino?

There can be a number of reasons why you would want to replace your Raduino.   For some, it is because their Raduino has been damaged. For example, it is pretty easy to accidentally damage an I/O port on the nano.   It is also possible to hook up the 8 wire connector incorrectly (mixing up the audio and digital connectors).   Of course, is possible to replace damaged components (such as the nano) without replacement of the Raduino as a whole.

However, it is more common to replace your raduino because you want to add either:

  • a processor upgrade (such as an arduino mega or mega mini pro (embed), or even a Teensy 3.2)
  • data I/O expansion to achieving other modifications.

Due to demand for product currently faced by HF Signals, the Raduino is not available for purchase separately. It was previously available for purchase separatley (at US$25 each) from HF Signals.   It is hoped that they will be available to purchase as a separate item again shortly when the back log of µBITx orders has been dealt to!

A number of Raduino replacements are on the market, and each will be discussed in turn with pros and cons.   You can, however, replace the Raduino with discrete modules yourself, and we will cover this option first.

Making your own replacement Raduino from discrete modules

The Raduino is made up of three sub-components:

  1. an Arduino Nano processor (soldered to the daughterboard)
  2. a “1602” display unit
  3. a “daughterboard” that has three connectors (one 16 pin connector to the µBITx main board, one 16 pin connector to the display unit, and an 8 pin connector for connecting to peripheral components (encoder, CW jack, power supply, etc.).   The daughterboard also hosts a 5v regulator and the si5351a clock generator chip.

You can replace the Raduino yourself by using perf board or similar to mount an Si5351a clock module, a processor, and a regulator (or buck power supply) and possibly a 5v/3.3v level converter.  A level converter is possibly not essential (the Raduino doesn’t have one). The most commonly used option for the Si5351a clock module is the Adafruit module.  It has a built in level converter.

A Si5351A Synthesizer  is also available from

You can use a standard 7805 regulator, or you could use a cheap buck power supply.  Make sure it will take at least a 0.5A draw.  You will need to make sure that it does not generate hash.    If using a regulator it would be advisable to include a 10 ohm 3 watt resistor in series with the 12v power in, and probably provide for RF bypassing and smoothing with a couple of capacitors (0.1µF and 47µF or similar on the output side of the regulator.

Processor options will be discussed in a separate article.     Other than the power supply, it should be possible to connect up wiring  using “Dupont” style connectors from the processor to the si5351a Module and from the processor to the display and µBITx main board.   Most si5351a modules don’t include 0.1µF capacitors on the clock outputs, but these are required when connecting to the main board. Be sure to either mount the Si5351a module as close to the 16 pin main board connector as possible, or use shielded leads for the three clock signals.


Raduino UMax

Mike Hagen, WA6ISP has previously supplied Raduino X and Raduino XP alternatives to the builder community for the BITx40 units.  His Raduino UMax is intended for the µBITx and has some unique features.

He now has designed, built and tested a µBITx Raduino replacement.  This comes with the extra feature of having an i2c 16 port I/O expander on board. The Microchip Expander IC uses the Adafruit Library MCP23017 to create 16 more Digital Pins.

This replacement board is slightly bigger than the standard Raduino and has the Ardunio Nano facing towards the left rather than to the right.  It is intended to be attached to the original LCD.

Mike can provide it unpopulated, with SMD parts installed, or fully built up. Complete documentation is provided.  Write to him for more details.


The W0EB/W2CTX/N5IB “RadI2Cino” (pronounced rad ee too CEE no) is an I2C replacement for the Raduino and is sold by Jim Sheldon W0EB.These are only for the uBITX, not the BITX40 and other earlier models as the connectors are different.

This board is designed to utilize either a 1602 (16 characters by 2 rows) or a 2004 (20 characters by 4 rows) I2C LCD Display, instead of the parallel display originally included with the uBITX.  The display is NOT included.   In practice your existing display can be used with the addition of an I2C daughter board such as the one in the photo below:

The six digital I/O lines formerly used by the display can be used to run the CW keyer and a few other functions in a much more efficient manner (using software also supplied by W0EB/W2CTX/N5IB).

Current options available include:

  1. Bare Board (you supply the parts & you build it).
  2. Complete Kit of Parts (less the Arduino NANO, LCD display and display I2C controller) – you build it. (All parts except the NANO, display and display controller are included in the kit.)
  3. Completely assembled and tested RadI2Cino Including the Arduino NANO but less the display and I2C display controller.Assembled and tested RadI2Cino boards will be available by Special Order Only. They will require up-front payment by PayPal and up to a 1 week lead time to build and properly test).

All orders will receive the complete assembly manual which includes a full bill of materials, board layout diagrams and schematics in PDF form via email. The manual is available for download in advance of purchase.  The bill of materials, included in the manual, has ordering information for the parts. Parts suppliers are Tayda, Digi-Key and Mouser.

Email w0eb (at) cox dot net for ordering or further information.

Comparison of Raduino replacement options