Introduction: Safety Lamp for Helmet Cycling

About: Electronics Professor Retired.
This project presents the more simple and cheap way to make a small lamp of safety into the back of a helmet for cycling.

This lamp is very useful for, in addition to lights of security that should bring the bike under seat, cyclist have again in the back of the helmet on his head, and thus better their identification by drivers and other transport.

It requires that the person who wants to build this device, have basic electricity, electronics and safety knowledge, as well as, you possess a soldering iron pen, welding and solder paste, an arc with blade and a hand drill.

Electronic devices and the small 12V battery you can get in a store of electronics (such as STEREN, for example), the tube and PVC covers is achieved at any hardware store.

Step 1: Parts

The following materials are required to build this small security lamp:

• Electronic and hardware:
3 LED 5 mm flashing
1 switch SPST miniature
1 100 ohm resistance
1 battery 12V type 23A
1 ½ " pipe 3 cm long
2 ½ “ cover PVC
Wire breadboard
Solder and paste
1 drill 3/32 "
1 piece of sandpaper

• Tools:
1 soldering pencil
Tip tweezers and screwdriver
Small hand 1 drill
Bow with hacksaw

Step 2: Cut Tube and Caps

PVC  caps and tube cutting arc with blade is cut a piece of 3 cm in PVC pipe, and the edges of the tube are matched with the sandpaper. In addition, should be cut tops two rings approximately half a centimeter. In addition, there chipping the edges of PVC pipe ends with the sandpaper.

Step 3: Drill Pipe PVC

With a hand drill and drill bit, drill pipe PVC, making three holes on each side symmetrically.

Must also make 3 holes of the same diameter for the pins of the switch (although we will only use 2 terminals, the third gives a better locking switch miniature).

Step 4: Weld the LEDs and the Switch

Weld  the LEDs, the resistance and the switch. Put the 3 LEDs in parallel, taking into account the polarity of these light-emitting diodes are placed. Normally the longer terminal is positive (or anode) of the device.

They are welded according to the presented diagram.

Step 5: Installation of the Battery in the Lamp.

Installation of the battery in the lamp. In the next step, is placed the battery with the positive pole facing the switch cover, where it will be a wire into a loop as a contact.

You must move the switch to check that the LED’s  works correctly.

Step 6: Put the Lamp in the Helmet.

Finally, we set pressure helmet lamp in one of the holes that normally have on the back of it. We could add tape double-sided for a better fixation. 

IMPORTANT NOTE: In case of not knowing how to use the hand drill or the soldering pencil and the bow with hacksaw, please consult with any person who knows about it to handle, to avoid an accident in your person.

Good luck in making this lamp, and I invite you to hop on your bike and pedal on the night walks that surely are organized in your city, to keep us healthy and happy.