Lights Form Factor Concepting

Ownership

Form Factor DRI	Contributors	Project DRI
Adrian Au	Steven Poung	Adrian Au

Research

Reference images

	Notes:
	Illuminated “light strips” from audi concept Q7
	Tesla model X
	Lightyear One
	Tesla Model 3 Teardown

High-Level Lighting Layout Concept

Design Considerations

Try to maximize the amount of design re-use between all the various lighting locations. This includes maintaining similar construction techniques, PCB designs, LED spacing/pitch, etc. in order to make our lives easier.

Terminology

In regards to PCB dimensions:

Dimension
LED Pitch	Constant for all light elements A spacing of ~8 mm between each LED should help to facilitate better diffusion/minimize LED “hotspots” (https://www.waveformlighting.com/led-strip-lights) High Density LED strips use 120 LEDs per meter (8.3 mm pitch) Medium Density use 72 LEDs per meter (13.9 mm pitch) Low Density use 30 LEDs per meter (33.3 mm pitch)
PCB Length	Determined by desired light element length (number of LEDs), LED pitch, heat sync length requirements, and mounting hole locations Constrained by amount of available space on either side of the light element
PCB Width	Determined by width requirements for heat sync and/or connector Constrained by amount of available space above/below the light element
PCB Depth	Determined by depth requirements for heat sync and/or connector Constrained by available space behind the light element

Form Factor Concepting

Headlights

Screenshots

High-level headlight architecture consists of thermoformed polycarbonate lens mounting to the flanges on the front of the aerobody. Headlight housing (material tbd) will be mounted to the rear of the aerobody panel (mounting method tbd). Light diffusion elements for DRL and turn signal to be housed inside the headlight housing. Electronics to be housed inside housing/on rear of housing.

Tail Lights (Rear Brake Lights and Rear Turn Signals)

Screenshots of Proposed Layout:

The LEDs for the rear turn signals and rear brake lights will live on the same PCB. This board will need to be as narrow as possible due to the tight space constraints above/below the board. Due to the space constraints as well as limited airflow, it is proposed that heat pipes will be used to transport heat towards the front of the car (where there is more space and better airflow for larger heat sinks/fins).

Dimension	Value	Notes
Light Element Size	36mm x 4mm for Rear Turn Signal 48mm x 4mm for Rear Brake Light	Can be made thicker (i.e 6mm vs 4mm) depending on how well light diffuses
LED Pitch	12mm (centre-to-centre)	Constant for all light boards Spacing between Turn Signal LEDs and Brake Light LEDs is 18mm (centre-to-centre)
Number of LEDs	3 LEDs for Rear Turn Signal 4 LEDs for Rear Brake Light	Please don’t hate me for using a different number of LEDs for the turn signals. It looked funny when both turn signals and brake lights were the same size
Max PCB Size (Length x Width x Depth)	100mm x 10mm** x 25mm	Max depth includes height of all components (i.e LEDs, heat sync) Board width should be as narrow as possible (something closer to 6mm would be appreciated) Using a 10mm board width, there is only 2-3mm of clearance between the outer surface of the aerobody and the board All other dimensions negotiable

High Mounted Brake Light and BPS Fault Indicator

As per the ASC regulations, the high mounted brake light and BPS fault indicator will live in the same relative vicinity, sharing the same viewing angles (30° from center in both directions and 15° up from horizontal).

Screenshots of Proposed Layout:

The LEDs for the high mounted brake light and for the BPS fault indicator will live on the same PCB. The LEDs should be located as close as possible to the top edge of the board. This will allow us to maximize the viewable angle of the LED by placing it as close as possible to the outer surface of the car (prior to accounting for light diffusion material).

Dimension	Value	Notes
Light Element Size	95mm x 13mm for Brake Light 8mm x 8mm for BPS Fault Indicator	Don’t expect nor require entire specified area to be uniformly illuminated to regulation brightness
LED Pitch	12mm (centre-to-centre)	Constant for all light boards Spacing between Brake Light LEDs and BPS Fault LED is also 12mm (centre-to-centre)
Number of LEDs	8 LEDs for Brake Light 1 LED for BPS Fault Indicator
Max PCB Size (Length x Width x Depth)	150mm x 10mm x 25mm	Max depth includes height of all components (i.e LEDs, heat sync) LEDs should be located as close as possible to top edge of board All dimensions negotiable

References

Electrical Page: MSXIV High Mounted Brake Light

Array Layout Page: Final Array Layout

File links or locations

Design Journal

Date (YYYY-MM-DD)	Notes
2020-05-25	Layed-out initial CAD model architecture: Headlight Lens to be thermoformed polycarbonate and will be glued and fit to aerobody flanges (side panel, hood, panel, bottom panel) Headlight Housing to be 3D printed in sections (relatively large part) and will be fastened or glued to interior of aerobody
2020-06-05	Took screenshots of CAD and added to confluence. Came to conclusion that headlight has the potential to be really big (see poorly dimensioned “drawing”). Will need to determine what maximum feasible size of lighting elements are for DRL and front turn signal
2020-06-06	#LightingTaskforce meeting liked the “non-bulby” look. A common theme between “boring” headlights: looks too bulby. lol. Follow-up to investigate feasibility.
2020-07-03	Added tail lights section

Tail light Arrangement Concepting (Archive)