Wireless remote controlled rocket launcher with Atmel ATMega328 for Arduino - Version 2

Summary
This is the second version of the Rocket Launcher project. This includes improvements for safety, a microcontroller upgrade and additional features. With the maker community now so large this design will be based on the Arduino with custom hardware.

Improvement Summary

To improve the launcher design some items were considered.

1. Reverse Battery Protection
   Prevent false launches when a engine is fitted and the battery is wired in reverse
2. Igniter Connected
   Load (igniter) sense addition to show if the igniter is still connected
3. Low Battery A defined threshold and indicator showing the low battery condition
4. Alternative Transmitter and ReceiverAllow an alternative to the communications hardware
5. Improve User InterfaceAllow for interfacing to an LCD to provide more information and control
6. Upgraded MicroLarger microcontroller for the additional features listed above

Change Summary
Starting with the new Atmel microcontroller each of the improvements will be reviewed.

1. MicrocontrollerThe Atmel ATMega328P is featured prominently in Arduino designs and is a well established micro. This device lacks some of the features newer devices offer such USB interfacing on the 32U4, however it is also half the price
   

   

   ATMega328P (TQFP Footprint)

2. Reverse Battery ProtectionA high current diode with a low forward voltage (Schottky) added to the circuit to prevent reverse battery issues
3. Igniter Active
   Detection of the battery voltage on the the MOSFET drain to indicate that an igniter is connected, analog to digital (AD) conversion
4. User InterfaceLCD header integrated into the next circuit board with buttons for control and feedback
5. Alternative Transmitter and Receiver
   Multiple footprints for receiver hardware on the circuit board
6. Low Battery
   The Sealed Lead Acid (SLA) battery will be monitored with a Zener diode dropper with a resistor divider
7. Data Logging
   With all the new metrics being gathered it makes sense to add an SD card

Design Notes
Aside from the new micro some additional buffering will be added to protect against ESD and other forms of damage.

Part Selection
Up next the alternative transmitter and receiver, then handling the level translation for the SD card...