For my battery powered water leak nodes I wanted to add a clear lens to be able to see communication LED status on Arduino Pro Mini while maintaining reasonable water protection. The quick no cost solution was:

1. Drill small hole in node enclosure against LED location
2. Cover it from outside with masking tape
3. Put some amount of hot glue from the inside to cover the hole, wait till glue hardens, remove masking tape. And voila!!
   

sundberg84 Don't bother, I went through the hassle, downloaded Eagle and created readable PDF

@tbowmo Thank you, supercap idea works fine, my first experience with supercaps.

Sure, the curve is there. I am trying to make sense out of two points curve that is used in sketch for MQ2 sensor, CO gas. "point1: (lg200, 0.72), point2: (lg10000, 0.15)" while I see on the curve from datasheet (lg200, 5.2) and (lg10000, 1.3). That is why I am asking for help, sorry for not making it clear.

I think that it will be useful to put together some kind of functional guide pointing the user in which mySensors example the specific function or feature is implemented, for example: sending floating number, digital input debouncing algorithm, battery saving, node to node communication, GW to node communication, minimizing traffic between node and GW, etc.

Lack of support makes you think, so I figured out the "hidden" calculations in the sketch above and proposing the code modification to allow users to port the code to a different gas sensor using data taken directly from the sensor chart. Here are modified fragments of the code showing only CO curve for MQ2 sensor:

float CO2Curve[4] = {0.8,200,2.2,10};
//two end points are taken from the curve with two coordinates for each point
//in form of{Y1, X1,Y2, X2) where X is PPM axis, Y is Rs/Ro axis from the sensor chart for specifc gas
//then equation X=(Y-b)/m is used,
//where m is slope of the curve, b is Y axis intersept point
float Slope = (log(pcurve(1)-log(pcurve(0))/(log(pcurve(3)-log(pcurve(2));
float Y_Intercept=log(pcurve(1)-Slope*log(pcurve(3);

int MQGetPercentage(float rs_ro_ratio, float *pcurve)
{
{ return (pow(10,((log(rs_ro_ratio)-Y_Intercept)/Slope))); }
}

Does enabled myDebug and some Serial.print statements (with serial port disconnected) affect power consumption of the node?