| Schematic | PCBs | Assembly |
The Polar BCAM Side Head (A2040) is single image sensor and dual laser driver circuit with two lasers mounted on the printed circuit board. The lasers can be the LDP65001E, DL3147, or any elecrically and mechanically equivalent device. The two lasers we name emit ruby-red light in a rectangular cone. The base of the cone is a tiny light-emitting surface roughly 10 μm by 50 μm. A BCAM is an optical surveying instrument (Brandeis CCD Angle Monitor) consisting of digital cameras and laser diodes acting as optical point sources. The A2040 image sensor is the TC255P. The A2040 provides connection to both lasers and the image sensor through a single twelve-way flex socket.
The following versions of the A2040 exist.
| Version | Description |
| L | Black Polar BCAM Side Head |
| R | Blue Polar BCAM Side Head (mirror image of A2040L) |
All varieties of the A2040 will work with any Polar BCAM Head (A2051).
The A2040 provides two laser drivers. Each driver takes a common positive voltage and a negative turn-on voltage. See the A2049 manual for more information about laser output power.
The A2040 provides connection to its image sensor in exactly the same way as a TC255P Minimal Head (A2016).
The A2040 connects the packages of its two lasers together, and so will operate when the lasers are connected together by a metal mounting plate with two holes in it. In BCAMs, we anodize the aluminum surface of the holes into which the lasers mount, so that the lasers are not in electrical contact with the munting surface. The A2040 connects both laser packages together, and provides connection to them on the two V+ pins of its flex connector. To turn on laser A, you bring the voltage of input LDA down to between six and twenty volts below V+.
Given a step input on the LDA of -10V with respect to V+, the A2040 will turn its laser on to full power within 5 μs. When LDA returns to V+ again, the laser turns off.
Note: All our schematics and Gerber files are distributed for free under the GNU General Public License.