My PiHPSDR MK II Project

My PiHPSDR Controller MK II rev 2 Project

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page last updated 09/19/2020


Latest updates 9/19/2020

Updates on my experiences and some minor errors that I found while getting PiHPSDR  to work.

The larger 38mm Rotary encoders [Enc-6] like the LPD3806-600bm-g5-24c.
These parts will short out the +5V for the Enc-1 if the Encoder Washer, below, or Kapton tape on the PCB,
is not used to isolate the large metal ring on the top of the encoder.  This gives the effect of a failed IC2
LMZ22005TZ and can ruin the IC2 and the PCB.  Also these encoders are specified to run from 5V to 24V
and of the 4 that I have they ranged from 5.05 - 5.1 Volts minimum.  Unfortunately my LMZ2205TZ
did not put out enough "+5V" to make them work.  My surviving IC2 puts out 4.99V subject to the
accuracy of my inexpensive DMM.  I ended up using a 5.6k Ohm resistor from the switched 13.8V to pin 1
of the encoders which was an easy solution. The math on the LMZ2205 data sheet would indicate
that the expected voltage would be between 5.06 and 5.12 VDC,  depending upon the inclusion of R7 or not.
For the board that I over reworked, I used a self contained Buck Converter module from Amazon
that has 5A adjustable output [3/$8] to replace IC2.  If you would like a description of how these encoders work,
follow the link that follows Rotary Encoder Teardown.  Be sure that you enable the pull-ups
for the Enc-6/1 and save the settings or the amount of excess "5V" will not make any difference.

There is an error in the instructions of the pihpsdr-install.pdf which indicates that you should disable I2C.
If you do disable I2C the new controller software will not start.  It will begin and then drop back to the RPi desktop.
So ENABLE I2C to get the software running.

After many false starts I have both PCBs functioning.  I was experiencing some unusual behavior so
I decided that a fresh clean install would correct some of my initial incorrect settings, which it did.
The units are behaving much better now.  To facilitate the update I made a text file,
, to eliminate the tedious typing of the commands in the terminal window.
Just put the file in documents and open it to copy and paste the desired command string in the terminal window.

I am now "printing" the side panels for the case.  There are 4 side panels that are needed
and each is 5 inches long.  They will be glued together to make two 10 inch sides.
Each piece takes about 3 hours to print.  If you are interested the stl file is below.
PiHPSDR_Side Channel_v4.stl
The large holes in the ends are for 4-40 brass inserts and alignment pins in the center where the glue will be applied.

New files: from 9/1/2020
Updated BOM: PiHPSDR_Controller_MK_II_rev.4_BOM.xlsx

3D Parts:
Note: Large encoder may short out +5V with out the spacer below

  for large encoder

New prelim Front Panel Files:
K9IVB PiHPSDR MKII FrntPnl Holes-prelim_6112020.xlsx

I have two functional units but have some difficulty getting the buttons and encoders configured.

It is suggested that you also look at the older info below for some explanations.

I do have a 3D printed side rail design to go with the faceplate.
It requires 4 pieces, two to a side that will need to be glued together

Current design files are available at 

The information below is a supplement based upon my construction approach. 
A commercial version of this unit will become available from:


Updates 6/2/2020

Below is the front panel I plan to construct, but with some different graphics.
Changed the rectangular push buttons to round to make home construction easier. 
There are two Front Panel Express design files in the
download along with an  X , Y drill file [PiHPSDR_FP_Holes_K9IVB_05032020.pdf]. 
I have not been able, so far, to reconcile the drill file for the Front Panel with the PCB drill file with any degree of accuracy. 
In the future I plan to glue a copy to a piece of cardboard and drill out the holes after I finish building up my 2 PCBs

I am planning to convert to all English  measurements: 10" x 5 1/2" to 6" panel, still subject to change.

* * * * * *

The attached [almost] fully sourced BOM and other preliminary information
will provide some choices between the rectangular pushbuttons and the round style
with some alternative case construction ideas.

Note: After putting down the 42 10K 0805 resistors on the "front panel side" [they do just fit]
of the PCB I have concluded that the parts should have been 0603 [Mouser #
Also missed counting R10 which is 0805 ! Will correct BOM after finishing assembly & test.

Two BOM errors
D2 should be BAS16J [Mouser # 771-BAS16J115] not BAS16W [wrong footprint]
L1,2,3,4 completely wrong part, should be Mouser # 623-2743021446 [last digit 6 is bulk 7 is T/R]

Another part error
R2 on Schematic is 620 Ohm and BOM is 680 ohm.
 620 Ohm is correct value to get 5V.

Still another error
The 2x20 header needs to be at least 13.58mm high so that the USB sockets clear the PCB


The BOM also has a choice of 4 dual rotary encoders or 4 single rotary encoders
which are interchangeable up until you solder them into the PCB.

* * * * * *

If a couple of zeros after the first significant digit of the Front Panel Express parts do not scare you off, you might consider ordering the parts from that vendor.  The DL2RMM design has a deeper case and provision for a Hermes-Lite 2 as well.
NOTE:  If you are using the large 38x35mm D encoder [ENC6] you will need the bigger Profile 2 extrusions.


My approach will be to use some hobby plywood [1.5mm / 0.062" thick] or some window acrylic type material which is much easier to hand machine than the aluminum, especially if you want the small rectangular pushbuttons. This material could be used for front and / or back panels and sides with the Front Panel Express Side Profile Extrusions.  Another alternative is to just get some 3/8" to 1/2" thick hardwood [256mm / 10.08" Long] from Home Depot for the sides.
I am also redoing the panel to be 10x6in [254x125.4mm] which will be easier to construct
in the USA and will permit the use of wood sides.
Note: 1.  the Left hand side of the actual PCB should be only 0.07874in [2mm]
                      inside the panel, so that there is easy access to the Raspberry PI outputs.
  2.  Leave some clearance at the top of the panel for the other Pi I/O
which also overhang the top edge of the PCB.

Home Depot has some "plastic" sheets:
Plaskolite Non-Glare Picture Glazing UPC #  074507996548    8"x10"x0.050" @ $3.68
Optix Acrylic Sheet UPC # 769125010218    0.93"x11"x14" @ $6.67
Also    0.25":x2.5"x24" Poplar Board UPC # 728927310285 @ $2.58

Also now considering making 3D Printing [.stl] files for the side panels to fit FPE & wood sides.

* * * * * *

The original gerber files are available from github.  See the link at the top of the page. 
I ordered my boards from JLCPCB and they had an issue with the file extensions..
These drill files have never appeared in any gerber file viewer that I have used, with out modifications.
Below is a copy of the gerber files that I used to order my boards. 
The only changes that were made were to the file extensions.
The Rev 2 artwork properly grounds the three address pins [14, 15,& 16] on IC1 the MCP23017

1. Any Gerber file is completely readable in any text editor.
2. They usually contain comments, with some descriptive information about the files. 
3. If you wish to decode the actual data, not in the comments, you will have to refer
       to  the Gerber and Excellon formatting documents [see links below].
5. Spec: The_Gerber_File_Format_specification.pdf
6. Excellon:


Free On-line Gerber Viewer:


* * * * * *

Stay tuned

You can contact me with QRZ info