Arduino Uno R3 Wiring Page

The choice of the Uno R3 was very simple --- it was in the junk box! I was not constrained by size since I had already chosen another junk box item, the 16X4, for the display. This has actually worked out well!

To interconnect to the Uno I used right angle pin headers that on one end plug into the Uno and then simply soldered the wires to the other end of the header. Actually if was necessary to swap Uno's there are four major header sections and they are easily plugged in or out. I used a very clever mounting method for the Uno. My approach used the mounting bolts for the 16X4 display and in place of a nut I used 1 inch threaded aluminum pillars. The standard hardware is 4-40 and in between the back panel and the display I fitted a 6-32 nut which acts as a spacer. I installed a 16 pin socket into the 16X4 display and it is into this socket that the I2C back pack plugs in. Thus only 4 leads go from the Uno to the display and these incldue th +5, Gnd, SDA and SCL. But the soldering of the socket means exposed solder connections on the front of the display that could otherwise short to the front panel.

So the install sequence is 1/2 inch long 4-40 bolt through the front panel. the 6-32 nut spacer, the display and then the 1 inch aluminum threaded pillar. The I2C backpack / socket combo is less that 1 inch high so fits with int the area of the pillar. Next I cut a piece of the wonderful Home Depot flashing galvanized metal and its size was big enough to hold the Uno and the Si5351. Thus the whole LCD Display/Uno/Si5351 is a unitized assembly. You will also need some spacers and pillars to lift the Uno/Si5351 off of the back plate..

For connections to the Si5351 I used some small cutoff pieces of aluminum angle stock and fitted one side with an RCA connector and on the opposing face there was a screw hole so that the bracket mounting bolt passed through the right angle stock through the sheetmetal backing plate into the backside of one of the four mounting pillars. The pillar on the upper right side (as seen from the back) serves as a mounting location for the small circuit board that reduces the amplitude and shapes the output of the 988 Hz TUNE Tone. The RCA connectors from CLK0 and CLK2 are visible in the left side of the photo. I2C backpack is right behind the UNO/backing plate.

BTW should you need to refresh the sketch code the input port is right at the top of the unitized assemblythus easily accessed. Now that is thinking ahead!

Wiring to the Uno

Pin #
VFO Select (Ground to Select)
Tone Pin Output
USB/LSB Select (Ground to Select)
TUNE Initiation (Momentary Ground)
Step Tuning Change (Ground to Select)
SDA ~ (Si5351 and LCD )
SCL ~ (Si5351 and LCD)
Si5351 and LCD
Encoder, Si5351, LCD, Vin & 3 Switches
9 VDC from 3 Terminal Reulator
MOX switch not connected to the UNO