Reliant on every other system, the flash is EQUiSat’s centerpiece.
The flash circuit is currently being prototyped with several different models in consideration. Below is the most simplistic representation of the flash circuit:
The central microcontroller (here represented by an Arduino Uno) controls the gate of two FET switches. The circuit operates in two phases:
Charge Phase, during which the top switch (P-channel) is opened closed, allowing the central capacitor to charge up.
Flash Phase, when the top switch opens, and the bottom switch closes (N-channel) allowing the capacitor to discharge through the LEDs in a fraction of a second.
Problems currently being faced with the flash circuit include:
- heat sinking
- reduction of resistance between the batteries and the LEDs
- the production of a constant current through the LEDs
The microcontroller (MC) serves as the brains of EQUiSat’s system. EQUiSat will harbor no uplink capabilities, so all general housekeeping and flash control will be totally automated, preprogrammed on the microcontroller.
The MC is entirely programmed using an Arduino Uno. EQUiSat has no need nor space for the entire Arduino board, though, so the Uno’s central microcontroller ATmega chip has been transplanted into our circuit, using the peripheral circuit shown
This makes programming and implementation of the MC extremely simple and repeatable––far easier than working directly with Atmel products and software.
Below is an image of the Uno’s microcontroller transplanted into a breadboard equipped with the above peripheral circuit, controlling an LED:
Using the technique specified above, the Uno’s ATmega microcontroller will be pre-programmed and tested, and finally transplanted into EQUiSat’s flight model circuit.