Deployment Logic

Introduction

The activation of the Optical Deployment Sensor (ODS) can be triggered by either one of two independent deployment sensors on the CubeSat: the button and the photoresistor. The digital button is the primary deployment sensor but if a threshold value of 150 (0-1023 range) is reached on the photoresistor, this is registered as a deployment event and the photo capture sequence is initiated. Both values are read from the sensors through their respective monitors, with a short delay between the button and photoresistor monitors.

Before accepting either reading as evidence for a successful deployment, a validity check occurs, resulting in the following three states:

1. Both sensors are valid --> either sensor can trigger a photo, with the button being checked before the photoresistor
2. One sensor is invalid --> the sensor with invalid data is disregarded, and the other sensor becomes the primary deployment sensor
3. Both sensors are invalid --> in this case a photo is taken after a hardcoded delay

If a valid deployment reading is not detected by the end of both mandatory and regular burn modes, the photo capture attempt is aborted and the CubeSat returns to the Armed Transmit mission mode.

Diagram of camera activation logic