2 part video showing how to tie the TP4056 and MAX17043 boards together and to an arduino pro mini.
Part 1:
MAX17043 LiPo Fuel Gauge connects to Arduino via I2C #1 – 09:07
— Julian Ilett

Part 2:
MAX17043 LiPo Fuel Gauge connects to Arduino via I2C #2 – 07:29
— Julian Ilett

I am seeing the same as AWI, same version of Chrome on Windows 7. Not that noticable until you hover over the grid icon:

2 part video showing how to tie the TP4056 and MAX17043 boards together and to an arduino pro mini.
Part 1:
MAX17043 LiPo Fuel Gauge connects to Arduino via I2C #1 – 09:07
— Julian Ilett

Part 2:
MAX17043 LiPo Fuel Gauge connects to Arduino via I2C #2 – 07:29
— Julian Ilett

This is not a very easy thing to accomplish. You COULD wire the relay to replace one of the 3 way switches but the controller would not be able to tell what the state is of the other switch (or the light), just what the state of the relay is. The 3 terminals on the relay correspond to the 3 terminals on a 3 way switch. They are labeled Common, NC (normally closed) & NO (normally open). The Common would correspond to the terminal the hot or light is connected to (depending on which one you replace) and the other 2 would be the "travelers". However, any 3 way home automation switch has you replace BOTH switches, one with a master and one with a slave. The master is the one that actually controls the state of the light and the slave lets the master know to change state.

@naveen
You can use the analog pins as digital io. It should get you to 12 on the pro mini:
http://waihung.net/arduino-tip-turn-your-analog-pins-into-digital-io/

@Yveaux I've seen wiring diagrams for FTDI CTS either not connected at all or tied to GND. Sparkfun's tutorial on the pro mini 3.3V shows they tie CTS to GND. See the schematic of the Pro Mini v-11 right after the picture of their FTDI Basic Breakout about halfway down the page https://learn.sparkfun.com/tutorials/using-the-arduino-pro-mini-33v

I tried everything I could think of, including switching from version 1.0.5 of the Arduino IDE to version 1.5.7. Still get the same results, a conflict between my sketch trying to define the PinChangeInt functions and them already being defined in MyGateway.cpp. So I turned on verbose logging in the compiler and see it is hitting every .cpp file in the MySensors library folder. So I decided to try something else, compiling one of the example sketches. Well, it looks like the compiler is including at least something from MyGateway.cpp in every sketch. Here is what I found:

Compiled example sketch BatteryPoweredSensor -

With MySensors library folder as distributed:
Sketch uses 17,732 bytes (57%) of program storage space. Maximum is 30,720 bytes.
Global variables use 476 bytes (23%) of dynamic memory, leaving 1,572 bytes for local variables. Maximum is 2,048 bytes.

Removing MyGateway.cpp from the MySensors library folder:
Sketch uses 17,146 bytes (55%) of program storage space. Maximum is 30,720 bytes.
Global variables use 443 bytes (21%) of dynamic memory, leaving 1,605 bytes for local variables. Maximum is 2,048 bytes.

Compiled example sketch BinarySwitchSensor -

With MySensors library folder as distributed:
Sketch uses 14,766 bytes (48%) of program storage space. Maximum is 30,720 bytes.
Global variables use 436 bytes (21%) of dynamic memory, leaving 1,612 bytes for local variables. Maximum is 2,048 bytes.

Removing MyGateway.cpp from the library folder:
Sketch uses 14,190 bytes (46%) of program storage space. Maximum is 30,720 bytes.
Global variables use 403 bytes (19%) of dynamic memory, leaving 1,645 bytes for local variables. Maximum is 2,048 bytes.

So, the compiled sketch is using 586 bytes more storage and 33 bytes more dynamic memory when MyGateway.cpp is present in
the MySensors library folder. Both sketches seem to run fine compiled without MyGateway.cpp.

MyMQTT.cpp is a gateway for a different controller, right? That one has no effect on the size of the compile sketch whether it is present in the folder or not. So there is something strange about the way MyGateway.cpp is constructed, it puts something in the compiled sketch that doesn't seem to be needed but doesn't generate any compile errors if it not present.

I see there is an update to 1.4 that has been released. I have not tried that yet. What is the recommended method for installing the update? Just download the full zip and overwrite all the files?

@hek

Well, that was too easy! Now all I have to do is resolve the compile error I get when including the PinChangeInt library without removing MyGateway.cpp from the MySensors library folder, being discussed in http://forum.mysensors.org/topic/347/1-4-error-compiling-with-pinchangeint-h-library-file

@hek
Nope, just downloaded and installed PinChangeInt in the libraries separately and tried both including it in quotes and <>. I misread the error message originally, it looks like the compiler is looking at MyGateway.cpp while it is compiling my sketch and reporting the PinChangeInt functions are already defined in MY sketch.

The original way I tried to include it:

include "utility/PinChangeInt.h"
MySensors\MyGateway.cpp.o: In function PCintPort::enable(PCintPort::PCintPin*, void (*)(), unsigned char)': /utility/PinChangeInt.h:366: multiple definition of PCintPort::enable(PCintPort::PCintPin*, void (*)(), unsigned char)'
Battery_Powered_SceneController_Pin_Change.cpp.o:C:\Users\Paul\Documents\Arduino\MySensors\libraries\MySensors/utility/PinChangeInt.h:366: first defined here

Using the separately installed PinChangeInt libarary:

include "PinChangeInt.h" in my sketch:
MySensors\MyGateway.cpp.o: In function PCintPort::enable(PCintPort::PCintPin*, void (*)(), unsigned char)': /utility/PinChangeInt.h:366: multiple definition of PCintPort::enable(PCintPort::PCintPin*, void (*)(), unsigned char)'
Battery_Powered_SceneController_Pin_Change.cpp.o:C:\Users\Paul\Documents\Arduino\MySensors\libraries\PinChangeInt/PinChangeInt.h:366: first defined here

Using either include, I can get it to compile without error if I removed MyGateway.cpp from the MySensors library folder.

BTW, how do you wrap code fragments to display properly in the forums?

I have worked out the logic to use the PinChangeInt library to have multiple buttons wake a battery operated scene controller so I can make a MiniMote type clone. This sketch framework should also work to make a battery operated door/window sensor that can handle multiple switches. The only problem is I can't use the built in sleep function in 1.4, the interrupts that PinChangeInt generate doesn't cause it to exit. I have been able to port part of it out of the MySensor.cpp library. I found I can call LowPower.powerDown without having to do anything special but haven't figured out how to call RF24::powerDown().

I ran into a problem with the way the MySensors library folder is laid out. I am trying to modify a sensor sketch to use the PinChangeInt library located in the MySensors\utility folder. I am working on using it in the SceneController example posted in this forum topic http://forum.mysensors.org/topic/256/scenecontroller/9, but seeing it with any sketch. When I include the PinChangeInt library into the sketch using:
include "utility/PinChangeInt.h"
I get a bunch of compiler errors showing there are multiple definitions and saying they are already being defined in MyGateway.cpp. But I am not including that in the sketch. The only other includes are:

include <MySensor.h>
include <SPI.h>

I can get it to compile without errors if I move MyGateway.cpp & MyGateway.h out of the MySensors library folder.

Is the Arduino IDE trying to include everything that is in the MySensors library folder when it compiles? I also tried it on CodeBender and the same thing happens.

I've got another question about how the MySensor.sleep function works but I'll save that for a separate forum thread.