The design is using an opamp as a compined level converter and a schmitt trigger, in order to convert the HAN signal into a 3.3V compatible serial format. As the input levels on the opamp is much higher than our 5V supply, we are rectifying and smoothing the HAN signal to use for a supply here. (VDD)

As a power source, we've used a micro USB connector, providing 5V, just as this is cheap and easy. However, no part of the circuit will need any other power than the 3.3V, so any combination of power source and regulator that provides the 3.3V will do.

The ESP8266 setup is a rather standaraized setup and will allow for programming the ESP directly on the board, if needed. During programming, it might be neccessary to disconnect the incoming HAN.

Schematics

PCB

Componenet list

Name	Value	Part
C1	10uF/25V	P5148-ND
C2	100nF	BC1101CT-ND
C3	220uF/35V	1572-1706-ND
D1	1N4148	1N4148FS-ND
P1		609-4613-1-ND
P2	Female	S7004-ND
P3	Male	952-2262-ND
P4		609-1047-ND
Q1	BC337	BC33725TACT-ND
R1-5,10,11	10K	CF14JT10K0CT-ND
R8	100K	CF14JT100KCT-ND
R9	330R	CF14JT330RCT-ND
R12,13	47K	CF14JT47K0CT-ND
S1,2		450-1650-ND
U2	LM1117-3.3	LM1117IMPX-3.3/NOPBCT-ND
U3	LM358	LM358NGOS-ND

Note: The ESP8266 is not included here. It can easily be found on ebay etc