Old Camera Ideas and Documentation

Introduction

This page contains all of the camera research and development that was on the wiki before the final camera was selected. It has been moved to this location so as not to clutter the camera homepage, which contains information about the current camera. Dates of writing are shown wherever known, and the contents of each section are in chronological order.

Requirements

The system has to have two main stages - an optic, such as a lens, followed by a detector. The detector is a CCD or CMOS chip which picks up the focused light from the optic. Typically, previous missions have flown lenses, such as Aalborg.

Dr Bannister has suggested that for the MRR it would be best to have two possible designs, one for an in built lens and one for a pinhole system.

Lens Optic

  • Not conjugate imaging, as we require a minimum working distance

There are two possible methods of making the lens optic. The most simple, and preferable, would be to use Harsh Environment Lenses. However, these may not be space qualified. A possible maufacturer of useable lenses can be found here.

If these should not prove viable, the optics could be made using a doublet system of two archromatic lenses. There is a broad range available, offering a lower cost solution and freedom in method of attachments, but would require careful calibration.

Previous missions

To study the CMOS sensors used in previous missions, two particular examples were looked at. These were the Aalborg and Devitech Cubesat, and the University of Tokyo Program, Cutesat-1.7 and Sharp (#1 &#2).

CMOS Detector

To make the detector for the camera, the basic idea is to buy a simple, off the shelf CMOS detector, possibly a webcam, and repackage it. The most likely form of repackaging is going to consist of reconditioning the board that the components are on and possibly replacing a couple of the components to make the entire thing space worthy. The lenses may also have to be re-fitted. If they are housed in plastic they will have to be remounted in a metal casing instead. If the lenses themselves are plastic, then the HEO or achromatic lenses discussed below will be needed.

Quasar Electronics

Quasar Electronics' sole CMOS digital output camera, the C3188A is a digital output, 1/3" format CMOS, running on a 5V (+/-5%) input. There are data sheets available for the camera and the CMOS chip.

Figure 1 Figure 2 Figure 3
PLM-CAM-C3188Back-702-1
PLM-CAM-C3188Front-703-1
PLM-CAM-C3188Front2-704-1

Figures 1, 2 & 3: The back, front, and front minus the camera module of the C3188 respectively

Cypress

Cypress have two CMOS sensors that are designed specifically for the radiation environment of space, in their STAR-1000 range.

Two chips are specified, both being optical, monochrome CMOS sensors that are radiation hardened and treated specifically for the space environment. The STAR-1000BK7 is recommended over the STAR-1000 as the temperature range is better. This temperature range is improved by a glass cavity filled with N2 gas. This increases the the range from 0-60oC to -40-85^o^^C.

Information on STAR-1000 and STAR-1000BK7

CMOS Sensor Pixels Pixel Size (microns) Array Size (mm) Chip Size (mm) Pixel Output Rate (MHz) Radiation Tolerance (kRad) Temperature Range (oC) Voltage (V) Power Dissipated (mW)
STAR1000 1024 x 1024 15 x 15 15.36 x 15.36 12 >250 0-60 5 <350 with ADC, <100 without
STAR1000BK7 1024 x 1024 15 x 15 15.36 x 15.36 12 >250 -40-85 5 <350 with ADC, <100 without

Omnivision, 19/11/2008

Another CMOS chip has been found that is just $59 and is already mounted on a board that has an I2C interface and 16bit RGB imaging. The chip requries a 5V input, however. A specification document is available, but due to copyright issues cannot be linked to from or stored on the wiki.

Sensor Pixels Pixel Size (microns) Image Area (mm) Scan Mode Minimum Illumination Voltage (V) Power Requirements (mW)
OV7610 640 x 480 8.4 x 8.4 5.4 x 4 progressive
interlace
20 lux at f1.4 (3000K) ±5 200mW Active
100µW Standby

Initial Design, 17/10/2007

A pin hole camera will be designed, for a minimal reduction in mass and volume than a camera with a lens optic. From this model, it is assumed that the light will enter the aperture and leave at a maximum angle of 45o from the normal to the aperture plane.

Links

Camera homepage
Payload homepage

Pinhole or Lens Camera?
Previous Cameras
Other information concerning the camera includes an evaluation of the optical flux expected to reach the aperture of the camera is shown here. This is only gets to the point where light would enter the aperture of the specific camera used, but can be extended once a selection has been made:
Optical Flux Evaluation

Pinhole Camera
Optical Photon Flux
Pinhole Camera Dimensions
Pinhole Camera Ground Coverage

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