PDF of a DIY Propeller Transformer board that adds ADC and I/O via ribbon cable.

LoopyByteloose

Hi all,
This is a single sided design in Eagle that can exploit the Propeller Quickstart or any other Propeller board with the 40pin header.

The design is spefically intended for DIY creation of a single sided board. If one were to use a double sided board, the size would be greatly reduced.

What I have done is to create an adapter that will allow either headers or ribbon cable sockets to populate the board, added an MCP3208 ADC interface, and options for additional +5 or +3.3 regualted power.

I am sure the concept can be improved on by suggestion. But the main idea is to enable new users to interface the Propeller Quickstart and other board easily and reliably at low cost.

LoopyByteloose

After sleeping on things for a night, I am beginning to have doubts that providing a +5VDC alternative for the MCP3208 in the way I have was a good idea.

A. Output from the MCP3208 to the Propeller when in +5VDC operation might require a current limiting resistor of 3.3K or more in order to protect the Propellers i/o
B. It might be simpler to just have the ADC restricted to a 3.3VDC operation and 3.3VDC be its maximum reference voltage. This would eliminate confusion with rank beginners over how to configure the ADC for voltages beyond 3.3VDC.
C. It might be nice to include resistors for each ADC input that create a voltage divider for higher than 3.3VDC input voltages. Not sure adding abilities to rectify AC would be also worthwhile.