Laser Radar

Laser Radar Design

1D: Based on NEATO design. Please see NEATO for duplication work. This radar design is characterized by using a high speed line imager to create a simple processing triangulation sensor with tunable reactions to multiple light sources and high speed pulses (up to 5000/s).

2D: This is a time of flight radar design theory.

Stage 1: build a single point time of flight sesnor.

The best, low cost methodology I can think of for a single module is adding analog trigger/response circuitry to a PIC24/DSPIC with CTMU. Multiple modules (with individual lasers and optics) could be stacked into an array. Alternately, a single optic and laser line module could possibly be used with multiple receivers.

Low cost option:PIC24F04KA201

Fast integrated comparator option dsPIC33EP32MC202. This option can also range down to the centimeter range due to 1000x charge current capacity. (0.55mA)

Reference circuit for doing ranging over COAX. This can be modified for our purposes.

And yet another time measurement circuit, this time doing pulse width measurement.

How to pulse a laser pointer at nanosecond rates.

I'm looking into duplicating some the CTMU with discrete hardware. I'd prefer not to, but I'd prefer to be able to do multiple measurements simultaneously and feed an ADC MUX. So, the capacitor would be the sample and hold buffer and this would have a discharge resistor (?), a precision current feed. I'd want to capture both the rising and falling edge of the laser pulse with this setup so I could average the readings to determine the pulse center. Some experimenting could be used to put together a color to range chart to allow me to interpolate the reflectivity of the object based on the detected edge points, allowing better compensation. L

Stage 2:
Expand the system to minimize components (single laser line, multiple recievers). Cost will be critical.

Laser detection can be done via PIN or APD. APD's are expensive, but there's a lot of $18 Hybrid APD's (?) on Ebay from Pacific Sensor. Item Datasheet.

VCSEL laser available from Digikey 1.8mW, OPV380.

Time of flight reference with custom chip (but originally Actel FPGA). His professional versions are definitely 300-800? Lightware in New Zealand

Possible components. TI OPA615 may be able to do sample and hold or integrating at this speed.

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