Wednesday, September 5, 2018

CWTD.ORG Test Gadget mother boards

In the last CWTD.org podcast, we discussed 3 possible implementations of a standard 'Test Gadget' platform.  There seems to be a desire for a basic platform using a Nano and another more powerful version using either a Teensy or a ESP32.  One thing that is needed to be standardized is a common 'bus' configuration for the 'gadget' modules.  My original 'test gadget' platform, had started out as a test bed for evaluating the ESP32 as the primary processor I will use for some of my upcoming projects.  Later, after I saw the CWTD project I started building modules along that line.

Since I had a circuit board layout that would be workable with a few changes, I decided to modify it slightly.  This will bring out most of the available pins, that could be configured to closely match those available if using an Arduino Nano.  I came up with two board layouts and ordered 10 of each from a Chinese board house that I have been using for some time now.  After they arrived I started putting together the Nano version.  


Because of the memory available and processing power of the Nano, I decided to only have two connectors for the 'gadgets'. Everything is pretty standard for a simple Nano project, except that I added a separate 3.3 volt regulator instead of using the 3.3 volts from the Nano.  On the Nano the 3.3 volts is provided by the USB serial converter, and has limited current capability. The ESP32 is a 3.3 volt only processor, so I will power some of the 'gadgets' directly from 3.3 volts.  Since I want to be able to swap 'gadgets' between the Nano and the ESP32 system,  I added the additional regulator to take care of any 'gadgets' that need a hefty 3.3 volt supply.  The board has a connector that brings out the I2C signals and power for a I2C LCD display, could also be used with a small I2C OLED display if limited graphics are desired.  I also have pads for directly mounting a rotary encoder on the board.

While I was waiting for the boards to arrive, I had designed a case to hold the 'gadget rack' main frame.  And set my great new 3D printer to getting a home ready for the boards when they arrive.
It took a couple tries to get everything fitting the way I want them, but well worth the effort.  That is the thing I really love about using a 3D printer, the ability to make something that fits your project exactly, not just something you had to cobble up to make things kind of fit.

When I assembled the board I decided to mount the 'gadget' header connector on the side by the Rotary Encoder flush with the board instead of vertical like the other side.  This makes it easier to use the encoder, and allows any 'gadget' to be plugged in on either side without having to wire them up for a specific side.  

One thing I found was that the only I2C LCD display I had on hand was only a 8 x 1 display.  It worked for the initial test but have a couple 16x2 on order.  Now to get started on putting together the ESP32 version and then building a couple 'gadgets' to check them out with.

6 comments:

  1. DuWayne
    Great stuff. Are your mother boards available?
    Tks, Ron K6DNV/XE

    ReplyDelete
  2. I still have a few available. Contact me directly at duwayne@kv4qb.us

    ReplyDelete
  3. Hi Du Wayne
    Very good job. Please it's possible to send me Gerber files of this mother board ESP 32 and the mother board or Nano.
    Manu thanks
    73 QRO Gilles F1BFU French station in center of France

    ReplyDelete
    Replies











    1. here is a dropbox link to the gerbers
      https://www.dropbox.com/sh/1hpuddtcoixejzk/AAAtY7lUYRL9cXQrtuGK1Kdca?dl=0

      Delete
  4. Many thanks DuWayne. 73 QRO
    Gilles F1BFU

    ReplyDelete
  5. Hi Du Wayne

    I had the PCBs made from Gerbers files that you made available to me.
    Super FB and thank you very much.

    Can you do the same with the stl files to make the boxes.
    Is it also possible to have the gerbers for the VFO with ESP32.

    thank you very much

    Gilles F1BFU

    ReplyDelete