Here is a video of a man Overboard light I made using a Arduino Nano a 1w LED driver, Mercury Switch and battery pack
Here is a parts list and the arduino code along with some photos
Parts
LED Driver
DC5-35V 1W LED 350MA LED Driver PWM Dimmer Step-down Constant Current Module
https://www.amazon.com/DC5-35V-Driver-Step-down-Constant-Current/dp/B0183KF6MK
http://www.ebay.com/itm/2PCS-3W-5-35V-LED-Driver-700mA-PWM-Dimming-DC-to-DC-Step-down-Constant-Current/191827304101?_trksid=p2060778.c100290.m3507&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D40954%26meid%3D0e4235b05e91490ca3cc2930103c7610%26pid%3D100290%26rk%3D1%26rkt%3D1%26sd%3D191827304101
US $2.94
Description
1. 5-35V input range
2. Output 350mA?20mA drive 1-10 pieces 1W LED
3. Close support PWM dimming high output low on output.
4. Buck mode LED guarantee total pressure is lower than the input supply voltage 2-3V to work.
5. Ultra-small size design (length 3.6cm * Width 2cm), low noise, safety features.
6. High-efficiency, low consumption, stable chip to achieve energy saving and environmental protection projects.
7. Constant output current, low ripple. LED used to ensure security, stability, improve the LED light effect, reducing the lumen.
8. Overload, short circuit, overcurrent protection, to ensure the supply security.
9. Wide input voltage, VIN+ and VIN- is the input power input positive negative.
10. LED connected to the anode of LED+, LED- connected LED cathode.
LED
1W High Power Cool White LED Light Emitter 6500-7000K with 20mm Heatsink
http://www.ebay.com/itm/251373119457?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
$0.19
Mercury Switches
Glass Electric Mercury Tilt Switch 0.5A/20V PZ-101 Work Angle Sensor 10°
http://www.ebay.com/itm/10Pcs-Glass-Electric-Mercury-Tilt-Switch-0-5A-20V-PZ-101-Work-Angle-Sensor-10-/321813289401?hash=item4aed9119b9:g:xVQAAOSwT6pVr2zb
$0.31
Arduino Nano
Mini USB Nano V3.0 ATmega328 5V Micro-controller Board For Arduino-compatible WP
http://www.ebay.com/itm/Mini-USB-Nano-V3-0-ATmega328-5V-Micro-controller-Board-For-Arduino-compatible-WP-/122179553820?hash=item1c72780a1c:g:GJ0AAOSw8w1X~t-8
$3.95
Total Cost without housing $7.39
Arduino Code
int led=3;
int dot=250;
int dash=750;
int offTime=250;
int letterPause=1000;
int pause=6000;
void setup() {
// put your setup code here, to run once:
pinMode(led,OUTPUT);
}
void loop() {
// put your main code here, to run repeatedly:
digitalWrite(led,LOW);
delay(dot);
digitalWrite (led,HIGH);
delay (offTime);
digitalWrite(led,LOW);
delay(dot);
digitalWrite (led,HIGH);
delay (offTime);
digitalWrite(led,LOW);
delay(dot);
digitalWrite (led,HIGH);
delay (letterPause);
// now dashes:
digitalWrite(led,LOW);
delay(dash);
digitalWrite (led,HIGH);
delay (offTime);
digitalWrite(led,LOW);
delay(dash);
digitalWrite (led,HIGH);
delay (offTime);
digitalWrite(led,LOW);
delay(dash);
digitalWrite (led,HIGH);
delay (letterPause);
// now dots again:
digitalWrite(led,LOW);
delay(dot);
digitalWrite (led,HIGH);
delay (offTime);
digitalWrite(led,LOW);
delay(dot);
digitalWrite (led,HIGH);
delay (offTime);
digitalWrite(led,LOW);
delay(dot);
digitalWrite (led,HIGH);
delay (pause);
}