DIY Voltage Sensor For FrSky Telemetry

My DIY voltage sensor on board

Frsky radio system with telemetry enable receiver have an/a couple of analog voltage inputs (for remote voltage measurements). The ER9X Tx software allows the assignment of alarm thresholds to these analog inputs. When the voltage alarm condition occurs a beeper in the R/C Tx sounds off. To use the analog inputs the Rx needs a resistor based attenuator to scale the voltage. The voltage applied to the analog input must not exceed 3.3V, which is the sole purpose of the attenuator.

The attenuator is actually a voltage divider circuit which produce an output voltage that is a fraction of its input voltage. In our case when our flight pack is fully charge (12.6V), the max output of our sensor is 3.3V and getting lower proportionally to our flight pack voltage.

My DIY Spider Quad

Here is my first quadcopter build. I love how the TBS Discovery looks in the air, but i can't justified it cost for me to get one. And there is Reptile frame which also looks nice in the air but again it still cost a lot for me. Then i started to look for a free plans of a TBS look a like on the internet with which i could build one for myself.
Lucky me i did find it here -http://www.rcgroups.com/forums/showthread.php?t=1706111. Nick_P don't just share his plan of a spider quad for free but included a complete guide how to make one yourself in writings and a series of youtube videos.
Here is what i come out with...

DIY Attiny45/85 Programming Shield

It is just something i made up to make my life easier and to sharpen my soldering skills.
Arduino is totally new to me after a friend sharing his rc plane navigation lights project. It is just interest me to give it a try. Since then i keep trying to learn something new out of it.
This thing really makes me thinking 'Why the hell i didn't pay attention to my electronics classes before?'. It is actually interesting to be able to build something electronicky.

FPV RC Rover Using Smartphones

I initially built a servo driven RC rover for my son to play with and because i found it to be something i have to try for myself. Who would guess the rover just been driven by two normal 9g servos. Thanks to rctestflight.
I just take it a little bit further by testing it for a ground FPV platform. Inspired by a friend who uses two smartphones as an FPV gear for his quadcopter, i dig out my old Galaxy Ace.

My Surmount Face Lift

It has been long since i first set sail with this model sailboat Surmount from HobbyKing. Although i got it as a second hand owner from my fellow rcer who got himself a new and bigger boat. It is fast becoming my favorite model for weekends. Since i got it, i have change the rigging, change the rudder servo and change the jib sail. But a friend of mine who recently bought himself a Surmount has shown me what have he done to his boat, which catch my attention to do something more to my boat.