Nuts and Volts - September 2017

computer to the Uno USB port. Programming the ESP8266s (applies to ESP8266-01, Itead S20, and Itead Sonoff) will require use of a USB to serial (FTDI) adapter.

These are available from many sites, including

Bangood.com, SparkFun.com, Adafruit.com, and

Jameco.com.

Note that the ESP8266 boards all require 3. 3 VDC for programming and operation. The FTDI adapter you choose must have the option to operate at 3. 3 VDC because the read and write lines on the ESP8266 are designed for 3. 3 volts, and five volts will damage the serial port. The ESP8266 can draw up to 300 mA during operation, so your FTDI board must be able to supply 3. 3 VSC at up to 300 mA.

Most FTDI boards do not provide a voltage regulator that can handle the current demand of the ESP8266. If you have a low current FTDI board, you can use a separate 3. 3 VDC power supply to run the ESP during programming and testing.

To establish the programming mode on the ESP8266- 01, you need to energize the board with the GPIO0 pin momentarily grounded and all other control pins pulled high. Connect transmit from the ESP8266 to receive on the FTDI interface and connect receive on the ESP8266 to transmit on the FTDI interface. Connect the ESP8266 ground to ground or negative of the FTDI interface, and connect Vcc to + 3. 3 VDC. The FTDI interface you purchase must be installed on your computer for the Arduino IDE to be able to communicate with it.

To establish the programming mode on the Itead devices (S20 and Sonoff), momentarily press the

36 September 2017

Additional Details on X- 10 Communication Protocol

X- 10 sends the control signal to its modules over the power line. There are many potential causes for weak X- 10 signals. All rooms on one level meant longer runs of power wires to room outlets, and Ground Fault Circuit

Interrupters (GFCIs) were installed on many branch circuits.

GFCIs have bypass capacitors to minimize spurious tripping, but these capacitors shunt X- 10 signals to ground, preventing X- 10 functionality without repeaters.

Also, X- 10 signals become attenuated when they go through the power company transformer to reach the other side of your house wiring.

In addition, I have found that many home electronic components and uninterruptable power supplies contain bypass capacitors to minimize EMI and RFI interference, but these capacitors also shunt the X- 10 signal.

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