Lokking for help with Boushh helmet lights (LED's)

[klmscott12]

I am looking to install the lights in my wifes Boushh helmet, but I am a bit dazed at how to go about this.

Heres what i would like to do.
Place two rows of 15-18 green LED's (one on top and one below).
Get the rows to blink on and off for 1 second each alternating.
Use 2-4 9v batteries (2 if possible) housed with in the helmet.

I have gone through the RPF site search on wiring LED's and found some good ideas, but none that cover blinking. I know that I will need to use resistors on the neg line and have been to the calculator site below and even tried a few things to get an idea of which parts might be needed.

http://metku.net/index.html?sect=view&n=1&path=mods/ledcalc/index_eng

Using the GURU option at the bottom I entered the following values;
Supply Voltage

18 VOLTS (for 2 9v batteries)
Voltage Drop Across LED

2.2 VOLTS
Desired LED Current

30 MILLIAMPS
How many leds connected
30

This resulted in a diagram of 3 rows of 8 and 1 row of six and suggested theses;

Calculated Limiting Resistor R1
13.33 OHMS
Nearest higher rated 10% resistor
15 Ohm

Calculated Resistor Wattage
0.01 WATTS
Safe pick is a resistor with power rating of
0.02 WATTS
Calculated Limiting Resistor R2
160 OHMS
Nearest higher rated 10% resistor
180 Ohm

Calculated Resistor Wattage
0.14 WATTS
Safe pick is a resistor with power rating of
0.24 WATTS

All of this I can wrap my head around (sort of), I just have no idea how or where to insert a "blinker". I am not looking for super bright lights, just something to complete the helmet. I have also looked at this for options

http://www.ledshoppe.com/Product/led/LE5033.htm

and would be willing to go this route if anyone knew of something closer to the screen cap above.

Any help on this would go a long way in making life smoother.

Thanks in advance,

Mike.

 

[boushhfan]

Great pic. Where did it come from?

Regards
Boushhfan

 

[exoray]

My advice is to simply use one 9volt battery and a voltage regulator, rather then 2 9volts... And if you use 2 9volts wire them parallel so you stay at 9volts and have the extra run time, since you really don't need any more volts... Green LEDs are low power and a single 9volt will give you many hours of operation...

That aside there are a ton of blinking circuits online if you Google you just need to replace the load with your LED groupings...

If you are looking for a finished product that you just need to install feel free to PM me back and I can make you one to your specs... Something this simple won't be costly...

 

[ShackMan]

If you're wanting to make the entire row blink at once (vs each LED IN the row blinking), it would be a very simple circuit. I'd like to offer a couple fo recommendations to your design:

1) Don't use a voltage regulator, as it would be a waste of power (through heat disspation). The regulator wouldn't hurt anything, but is overkill for this type of circuit.

2) Run the LEDs at 20mA (maybe even 15mA) for longer battery life. LEDs are typically rated for 20mA, and the difference in light output from 20 - 30mA will not be worth the extra power used (on typical LEDs anyway).

Put as many LEDs in series as possible, to reduce current drain. 9V can drive 4 standard LEDs in series, so 16 LEDs would be 4 strings. At 20mA each string, you're talking 80 mA ... not bad (should last a few hours per battery, and you only have one to replace each time).

Good luck,


ATM
ShackMan

 

[klmscott12]

Thanks for the tips. I am sure I am not the only one out here with this project and this might just be the info needed to help some of the others to install lights as well.

 

[jackdoud]

I'll be doing this same project in the near future for a friend of mine. I was planning on using a 555 chip and 2 transistors, one NPN and one PNP. The output of the 555 would go to both transistors and alternatly trigger them. It's gonna be atleast a month until I get around to it but I'll post what I've got when I do.

 

[Fetthunter]

What happened to ShackMan? I've PMed him here and on TDH, but no response. :confused

Shoot me a PM if you read this, Alan!


J

-------

:::EDIT:::

Call off the hounds! He's been located!