Fire-TICs A-Si Camera Project

Project 1 - Camera based on Raytheon 2000AS core

This project takes the Raytheon 2000AS core and builds a portable camera with it. The Raythen 2000AS was one of a number of imager cores made in the late 1990's by major sensor manufacturers that were self contained and suited to simple 'screwdriver' camera build. You simply put power in and video came out. At the time silicon detectors were not under export control, so this core was popular with manufacturers outside the US as it simplified a lot of paperwork. Buildng a basic camera with these cores was pretty much a case of put in the right voltage and hook up to an analogue video monitor and away you go. The imaging is 160 x 120 pixels at 20Hz, presented as a 30Hz NTSC standard video, although the 2000AS is monochrome. The detector itself was novel at the time in being wafer level packaged something that is only just turning up with other manufacturers such as FLIR. This was also the first camera core that did not have thermal stabilisation and also did not use a chopper wheel.

The images above show the 'Core Kit' as supplied to OEM builders showing the flexible arrangement of the optical block on the end of the flexi cable / PCB.
The datasheet and user guide for this core, Raytheon public documents.

It should be noted that the sensor and the PCB are a matched pair. it is unlikely that any sensor will work well with any other PCB.

The main parts come from an Argus P4466 (Argus 3 ASi, the blue one), although the only proprietary EEV/Marconi parts used here are some mounting mechanics and the connector leads to core and display. The Argus 3 had a lot more in it as it could save images, colour them and adjust the LCD settings. As a hand held camera it also had batteries and a charging circuit. Even so, as the Argus 3 case was built for the much larger Raytheon BST core, there was a lot of fresh air inside !

A small number of 2000AS are available for GBP 150 plus shipping. These were surplus stock and so are effectively new and supplied with full wiring harnesses. for further details. Note that these are ONLY available to the EU as the cores are in the UK and UK export controlled.

The 2000AS core, and the more recent AS3500 and AS4000 cores, were used in Bullard fire camera products (notably in the T3 series) and also Raytheon's own end products such as the X100 spotting scope. It is described further here

Parts Used

Raytheon 2000AS core (optical block and matched PCB set)

Cable for Core

LCD display (this build used the 4 inch LCD from the Argus 3 camera)

Cable for LCD

A box

Power socket

Video socket (BNC, phono or whatever suits)

On-Off switch (this build used a P4428 switch)

Batteries (this build used 4 x lithium cells)

Variations on this project could omit the batteries and switch if externally powered, or omit the display if intended as a fixed camera. A video transmitter could also be fitted, even one from an Argus3, but care should be taken not to break local laws on video broadcasting. Fire services may have been able to get a license when a private user would not. Equally a fully sealed unit could be built if the donor camera had an undamaged germanium window, and an IP box was used.
The original data sheet for the Raytheon core is here.

Build Pictures

At the simplest level it is a case of cutting out suitable holes and fixing the bits into the box ! In this case the optical block is fixed in place in the base with 3M adhesive tape while the PCB set is fixed on pillars. The grub screw was removed from the lens to allow focussing, and it focusses down to 25mm / 1 inch with no trouble

	Lens. The lens can be made adjustable focus by removing the grub screw. This allows focus down to about 20mm / under 1 inch. It also makes it easier to fit into the box. In the fire camera version the lens gives a 50° field of view with an 8.5mm focal length. It is f/1 aperture.
	Finished camera imaging a soldering iron.
	Rear View [1] On Off switch, switch and label from a P4428, mounted with parts from an Argus 1 [2] Charge / power input [3] Video out - NTSC 30Hz
	Base. This view shows the core PCB set mounted in the new case with the optical block to the left.
	Lid. This view shows the box lid with a video LCD mounted in it. The LCD is from Argus 3 but needed extra wiring to flip the picture round.

The core and 4" LCD require 300mA at 10V. The core alone can use different supplies including 2 x 'AA' batteries and uses 0.8W (on low voltage input) or 1.2W if using the high voltage input.

Videos

Some images and short videos taken with the 2000AS core

Hot router and room
Close ups of a soldering iron, focussed at about 25mm / 1 inch.	Of note is how this core handles very hot objects as it uses simple temperature to video brightness mapping. The soldering iron drives the rest of the room to black, until entering 'EI' mode - electronic iris, which is a low gain mode. The two sensitivities are shown in the video
Indoors, unlit night. Shows underfloor pipe runs.
Outdoors street scene, daytime
Outdoors street scene, unlit at night
PCB inspection

Core wiring data

The core has a 13 way connector (type ?? probably JST) although only 4 ways are needed. A lead was supplied with the core kits from Raytheon as shown below. The RS485 allowed very limited customisations such as a custom startup image in place of the RCI logo. It would be expected that there were further functions hidden to end users, probably including sensor calibration.

Pin	Function	Notes
1	Power in +	6 - 32V. DO NOT EXCEED 33V
2	0V	Ground
3	Low Battery	Shows a low battery logo when grounded. Software version dependant.
4	RS485+
5	RS485-
6	Ground	Ground
7	Shutter	Ground to force a manual shutter / flat field correction
8	Video Polarity	Ground to select black hot imagery
9	Low Voltage in	2.5V - 4V an alternative to using pin 1, typically 2 x AA cells. DO NOT EXCEED 5V
10	Power Out	Connected to pin 1 via a diode to aid wiring.
11	3.4 - 3.7V out	To drive a display, 250mA maximum
12	Video Gnd	Ground
13	Video	NTSC video

There is also a 5 pin connector for a Kopin LCD, but this was not used for the project as described here. Type JST ZHR-5. Leads were not supplied with the kits and details are in the user manual. This was would used in Raytheon end products such as the X100 camera which used these cores and directly drove a Kopin 0.25inch LCD.

There are a couple of features to note if building your own variation on the camera. The core can be powered either from a 'high' voltage or from 2.5V - 4V, and it also has power out. For basic use, simply provide one or the other power source.

Display wiring data

The display has a 15 way connector (Molex 53261-1590) although only 4 ways are needed. There is also a 7 way connector to allow adjustment of LCD contrast etc with pots connected across 5V, this can be left disconnected. The rest of the pinout is shown below. The display is an CCFL backlight LCD panel with driver board attached. Care is needed if handling while on as the backlight needs about 3000V which is present on the board itself generated by the transformer with the warning label on it. It hurts !

Pin	Function	Notes
1	Horizontal sync	optional timing
2	Vertical Sync	optional timing
3	NTSC / PAL	Pull low to force PAL, high for NTSC. Floating is auto select
4	Input select	Default composite (pin 5) Take high to force use of RGB in (pins 6,7,8).
5	Composite video in	Input video
6	Blue video in	Blue of RGB component video in
7	Red video in	Red of RGB component video in
8	Green video in	Green of RGB component video in
9	Power Ground
10	Signal Ground
11	DC in	10V-13.2V
12	Signal Ground
13	S-Video	Video input
14	LR	Ground to flip picture left-right
15	UD	Ground to flip picture top to bottom

Additional control connections

Pin	Function	Notes
1	Vcc output	5V
2	Tint	Tint adjustment 0 - 5V
3	Colour	Colour adjustment 0 - 5V
4	Brightness	Brightness adjustment 0 - 5V
5	Contrast	Contrast adjustment 0 - 5V
6	Sharpness	Sharpness adjustment 0 - 5V
7	Ground	Ground

More about the Core

	The optical block simply contains a solenoid to operate the calibration flag, driven by the red and black wires. It is a relatively large block of aluminium mainly to reduce the rate of temperature change. The lower image shows the sensor mounted directly on the flexicable.
	The first PCB, 'Processor PCB', looks like it dealt with sensor correction and has as main IC's TI TMS320VC5410 DSP and AD7472 12 bit 1.25MHz ADC and an unidentifiable clock generator IC (perhaps custom ?)
	The second PCB, 'Reformatter PCB', looks like it dealt with producing the NTSC video image and has power supplies (MIC4680, LTC3401) There is a 24MHz clock, TI TMS320VC5410 DSP, and AD9708 8 bit DAC. It has the 'public' user connections of J1 and J3.

Final Thoughts

A similar camera could be built with later sensors from the Raytheon ASi family such as the AS3500. These later cores offered colour video and greater interaction with user controls.
As the cores tended to survive firefighter use (abuse) quite well, they can often be found in othersiw wrecked cameras. As such there may be a few cores available from Fire-TICS or fellow camera enthusiasts to enable similar projects if unable to locate a suitable donor camera. However the cores are now classed as 'dual use' so fall under Wassenaar export controls from the UK. Cores in the UK cannot be sent outside the EU without a license. The best approach initially is to ask on the forum. Some excess stock of these cores and similar was being offered (Nov 2017) in the US by SPI Infrared but again export controls applied so limiting sales to within the USA.

Back Home