[Arduino #12] LED helmet research

1. Which LED strip?

I figured out that there are many kinds of LEDs and many brands who make LEDs. Some stripes have digitally-addressable pixels, some don’t.

1). 144 LED/m Technical specs:

  • Maximum 5V @ 60mA draw per LED (all LEDs on full brightness)
  • 35 Watts max(about 7 Amps @ 5V). Max means on full white. On average about 1/3 to 1/2 the max current. Works only on a microcontroller faster than(>=) 8MHz.(Teensy seems to be fine with this criteria.)
  • 5VDC power requirement (do not exceed 6VDC) – no polarity protection!
  • Connector: 3-pin JST SM
  • Weight: 35.42g

Screen Shot 2014-09-22 at 9.01.34 PM

60 LEDs/m Technical specs:

  • Maximum 5V @ 60mA draw per 0.65″ strip segment (all LEDs on full brightness)
  • 18 Watts max(~3.5 Amps @ 5 V)

Screen Shot 2014-09-22 at 9.01.47 PM

30 LEDs/m Technical specs:

  • Maximum 5V @ 60mA draw per 1.3″ strip segment (all LEDs on full brightness)
  • 9.5 Watts max (~2 Amps @ 5V) per meter

Screen Shot 2014-09-22 at 9.02.02 PM

I found an European shop:

http://www.cooking-hacks.com/led-rgb-strip-addressable-sealed-1m

http://www.cooking-hacks.com/rgb-led-waterproof-flexi-strip-60-led-1m

Here are some info about watt:

AAA batteries can be measured using voltage for the most part. They are rated at 1.5 volts each and depending on the battery will depend on how much wattage is produced from those volts. It seems on average that AAA batteries have a measurement of a bit less than 2 watts per battery. This can go up or down, however, based on the amp level that the battery operates at.

Description of a Watt

A watt is a unit of measurement for the output of energy. It is also used in equations for the process of conversion to other energy sources. One watt equals one joule of energy or power second.

Formula For Figuring Wattage from Voltage

In order to accurately figure the wattage of a battery from the voltage of said battery you would also need to know the amps that the battery runs at. You can find this information online or from the manufacturer of the particular battery you are testing or using. Once you have that information the formula is; watts divided by amps equals volts or amps time volts is the total watts.

To accurately asses the question presented you would need to know at least two variables. Once you have two of the variable you can find the third.

Read more: http://www.doityourself.com/stry/how-many-watts-are-in-aaa-batteries#b#ixzz3E4NiKvNP

Here is a comparison of Energizer battery capacity and a possible candidate.

energizer

Screen Shot 2014-09-22 at 9.33.29 PM

This Lipo from Adafruit looks better than energizer. its spec is:

4.2V when completely charged to 3.7V. Capacity of 2500mAh. for a total of about 10 Wh.

Adafruit managed to place the battery like below. I don’t know how that’s gonna stay in actual riding. And when a helmet is suppose to keep you safe, I’m skeptical if it still holds the point.

flora_citibike-helmet-15

2. Board

Arduino is out of my concern due to its size. Teensy and Flora will be my choice.

3.Helmet

I first thought that I won’t buy Carrera foldable helmet but just use an ordinary helmet.

Screen Shot 2014-09-22 at 10.07.38 PM

Then I read this:

Screen Shot 2014-09-22 at 10.06.23 PM

Since I’m really trying to make something I would use daily, the safety is the most important thing that I can’t negotiate with….. Well, people mount Gopro on their helmet and do crazy stuff so I guess it won’t matter.

4. Wireless communication

Here’s a teensy tutorial:

Screen Shot 2014-09-22 at 10.23.19 PM

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