Before we build PC boards the hardware design was tested on this
breadboard. We also used the breadboard to develop the software.
At the left is an IO-Expander-EVM for the TCA9539 chip. This connects
via a CAT5 Cable to a Temperature sensor module which has a DS18B2
device. At the right the Prototype board has a
Cat-5 tail, a Small
PJRC SD Adaptor and a
The wiring of this module is show on the
Processor Module Pinning page.
The Huzzah developement board uses an ESP-12
module which is available from
at a lower price.
ESP library documentation is available at:
There is an
that is available for $2.40. It is not clear if this module is
certified as an FCC modular device. They appear to be software
compatible with the ESP12-E modules from Adafruit.
It is also available from
is available for $2.50, $2 quantity 50 and less in larger numbers.
It carries an FCC logo and appears to be certified as a modular
device. Discusson on line at: