Level Shifting and Tablet Building …

circuitfloor1Figure 1: The new tablet uses re-purposed materials on the circuit board floor.

This project is more involved than a simple exercise in converting 3.3 and 1.8 volt logic levels.  It also involves building yet another homemade tablet.  I have four of them now (2 Pi2’s, a C1, and a C1+).  The fifth one (being this XU4) will be the most powerful of the bunch.  So, in figure two we can see I’m beginning to lay out the new tablet…

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Using a Pi SBC with Shortwave Radio

BUTTERWORTHON-16DIP-SOC-5New Orleans Coast Guard weather fax operates at 4.317  4.344 MHz, so it is far outside of the default (7 MHz CF) filter bandpass of the BPF that I have in the little sidecar SDR.

Currently, there is no bandpass filter switching arrangement within the sidecar, so I have to swap the different 14 pin dip sockets in and out as I change bands (each DIP is loaded with the correct combination of components for the frequencies I wish to use).  It’s  a little inconvenient to do it that way …

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Homebrewing a Board for the MCP3426 ADC

circuit3426-g-ccoolleerr2

Figure 1The simple connection from the USBIO to the ADC

The ADC devices currently in all three of my “homemade” tablets are a little under powered, so we’re upgrading all of them to use 16 bit Microchip MCP3426 ADC chips. The smallest reasonably hand solderable chip package is the SOIC. Most of the newest, fastest most glam chips are not even available with old-time DIP packages anymore. This is seriously bad news for oldish guys like myself.

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