Wafer-thin High Output Rechargeable LED Flashlights
Wafer-thin High Output Rechargeable LED Flashlights
White Slice is a high output credit card-sized rechargeable LED flashlight, with a brightness of 45 lumens and thickness of 0.1".
White Slice is a high output credit card-sized rechargeable LED flashlight, with a brightness of 45 lumens and thickness of 0.1". Read more
This project will bring to market a credit card-sized rechargeable LED flashlight. The product has the same outline as a typical credit card, and the prototype is approximately 0.10” thick. The target maximum thickness for the production model is 0.105”. To put this in perspective, a credit card-sized gift card is approximately 0.03” thick, and credit cards are approximately 0.05” thick, so the flashlight is sized approximately 2 credit cards, or 3 gift cards thick. The flashlight uses a high power density lithium polymer battery, integrated circuit electronics, and 10 high output LEDs. Based on LED specifications, the flashlight emits 15, 30, or 45 lumens of light at a wide angle for superior flood light coverage.
This is not a beam-type light like some tactical flashlights. Please compare the following pictures not so much for brightness, but for light distribution. All pictures were taken with the same settings (ISO 400 F/2.0 exposure 2 seconds)
Because of its extremely small size, White Slice is not competing in the "may cause blindness" tactical flashlight arena. White Slice uses voltage and current regulation to deliver a constant illumination over the charge of the battery. Lower quality flashlights (that don't use voltage and current regulation) will claim higher light output, or longer runtime. This is because these flashlights can output more light- often for 10 minutes or less- and can run longer- at nearly zero light output.
White Slice is unique because it incorporates high light output in a very thin package. This light is the thinnest and also the brightness for the weight that we are aware of. It weighs 0.6 ounces (15 grams).
Most flashlights have a limited resistance to impact, measuring drops from 3 feet/1 meter. The White Slice design has extreme impact resistance! We threw it out a third story window onto asphalt; no damage. Between the light weight and flat form factor, we conjecture the final product will have better drop protection than any flashlight made to date.
Battery and Electronics
We've chosen to use a lithium polymer battery because the technology is top-of-the-line, holds a lot of energy, and can be charge hundreds of times. The battery is rated at keeping over 80% capacity after 300 charges, which is exceptional for a rechargeable battery. To maintain the life-cycle of the battery, it needs to be carefully charged and discharged. To make this sensitive process simple, the electronic circuit includes a controller to manage the care of the battery. So, there is no risk of over overcharging, over-depleting or otherwise damaging the battery!
The LED driver circuit automatically adjusts voltage to the LEDs to maximize battery life and maintain brightness. When the battery is low, the LEDs flash to let the user know it is time to recharge.
White Slice uses two fail-proof switches! Have you ever had a flaky flashlight switch? It's the worst. The switches are electronic and have no moving parts! Additionally, during production the printed circuit board is immersed in liquid gold, so the switches are gold-plated. Gold has great corrosion resistance, so you can count on the switch pads working perfectly for a very long time.
How many flashlights in this box were accidentally left on? The only certainty is that the White Slice is not on. White Slice will only operate when you are holding it, so it is not possible to be left on by mistake.
Through the prototyping phase, we determined that we need a fairy rigid case to protect the electronics and battery. To get the rigidity, we determine the need to use special materials in the case(not typical plastic as used in the prototypes). The most cost-effective way to make a specialty material case is by creating molds and injecting the liquid-hot material into the mold. We haven't decided which materials to use yet; but we are currently working with the experts to determine the best material for the application.Two designs in one! Introducing Green Slice!
The White Slice was designed to support a second flashlight model using the same printed circuit board and injection molds. This alternate configuration does not use the bottom of the printed circuit board and doesn't use the bottom of the injection molded case. Hence Green Slice was born! Green Slice is thinner and lighter. It has half the LEDs (5), therefore half the brightness and twice the run-time. For Kickstarter only! We will do an injection molded plastic run in Kickstarter green for the Green Slice case.
The bottom of Green Slice has a vinyl sticker (shown above left in black), but the production vinyl sticker graphic will be created by a backer! If you are or know an artist, have them submit a design! Green Slice recipients will choose their preference from the submitted designs.
To date, everything has been designed, prototyped, and assembled in the USA! We desperately wanted to have this product made 100% in the USA, but have determined that it just isn't cost-feasible. We have conceded to have the printed circuit board (PCB) electronics made (and populated with electrical components) overseas. The rest of the product will be designed, made, and assembled in the USA.
Two different electrical prototypes have been created in order to work through any design issues and prepare for product launch.
V1.0 was 22 lumens and 0.10" thick. We experimented with different cover materials, such as carbon fiber (very strong for the weight), and acetron, a fairly rigid but easily machinable plastic. V2.0 has the same thickness, but doubles the light. This sacrificed the rigidity of the case, which is shown here in acetron and polyethylene (another plastic). Rigidity, and production speed, are the main reasons for creating an injection-molded case.
- Oct-Nov: Kickstarter
- Nov: Send out short-leadtime rewards (shirts, etc)
- Nov-Dec: manufacturing of final PCBs. Creation of injection molds.
- Dec-Jan: first case components injected, molds perfected. Production parts injected.
- Jan-Feb: All parts in-house, assemble and distribute product.
The flashlight case is the longest leadtime item, but there are several other items that will be procured simultaneously:
Orange Slice Polos, USB Cable, Packaging, and stretch goals, as applicable.
Thanks in advance for helping to make this project a reality!
Risks and challenges
Technical risks and challenges are minimal, due to the proof of concept through a series of working prototypes. A challenge we face is securing a timely production schedule with the injection molding company. Preliminary discussion with several companies has demonstrated that the mold creation process takes about 5-8 weeks. Securing a production timeline for the printed circuit boards (PCB) is less of a risk, as the lead and turnaround times can be very quick.
There is always a risk of unforeseen incidents such as a lost shipment and other manufacturing delays. We will make very effort to minimize delays and deliver on schedule.
- (30 days)