Ornithopter Project - Circuit advice NEEDED.

Using Arduino Project Guidance
#1

I am a third year engineering student. My university project involves building a working ornithopter. Currently I am nearing end of my construction phase and moving onto circuit/coding phase of the project. Problem is I am not good with electronics and require some guidance and advice. I would really appreciate if you guys could help me out.

I am using Arduino Mini to be the microcontroller on my UAV. Other electronic parts that are part of the UAV include 2 high torque servos, a receiver and a battery pack(specifications of each components below).

So my main problem is how do I go about connecting the components, do I use a breadboard (adds more weight) or do I solder things directly to each other? If I do solder things directly would I require resistors in between the components?

Another question is what should the circuit look like? How do I connect the battery pack to servos, arduino and receiver? Since I am using 2S LiPo battery pack (7.4V), I know I can connect the battery pack directly to arduino but do I connect the servos in series to the battery or do I make 3 wires come off the battery pack and connect each component (servos, receiver and arduino)?

Another thing I have previously used Arduini UNO but never have used Arduino Mini, I know to upload the code I need the external USB to serial attachment, is there any other essential components I need (other than wires)?

It is a lot to ask but I would really appreciate any help since I am not an experienced with electronics.

My component specifications:

2 of these servos:
Torque @ 7.4V: 25 kg/cm
Speed @ 7.4V: 0.10sec / 60 deg at no load

Battery pack:
LiPO 2S 1000mAh 40C

Receiver:
Spektrum AR610C DSMX 6CH Coated Sport aircraft RECEIVER
Band: 2.4 GHz
Input Voltage: 3.5V to 9.6V

Arduino Mini

Transmitter:
Spektrum DX7S

#2

do u have access to a schematic capture and CAD program like CadSoft EAGLE??
start there and draw ur circuit, then layout a shield that fits ur UAV needs

#3

Most important is a single (main) power switch, so that power is supplied/removed to all components at the same time. After that switch you can use distinct + lines to every component (star topology), so that the currents on these lines don't add noise to the lines to other components. For the same reason all Gnd lines should be connected to the processor board Gnd pin. Use thicker wires for the battery and servo power and ground lines, the signal lines can be as thin (light) as you like. Keep together the lines to each distinct module, for best noise immunity.

Capacitors can/should be added to the components, to stabilize their power supply voltage. One of high capacity for heavy load changes (servo movements), and a fast (ceramic) capacitor for spike suppression.

You can add protective resistors (1-10k) to the signal lines, if you like.

A breadboard is fine during development, but once you got the circuit right the lines should be connected directly to the board. Breadboard connectors tend to wear out, lose parts or connections due to vibration of your device. Where "directly" does not necessarily mean soldering, I'd add connectors which allow to add/remove all the components to the processor board without an soldering iron.

#4