Many times. I used the bicycle in the night and I dont have a lights!. So i decided a make a circuit that blink leds with few components and also very easy.
I also want the light, once installed, to be invisible and the back part of the seat offered a small space
Step 1: Choose the Retroreflector
I have 2 retroreflectores so I decided to use the biggest one that allows me to leave the pcb embedded and it is also red!
Step 2: The Circuit and Materials
since my goal was to use few components, use a ne555 ic as a hysteretic oscillator with which I achieve approximately 7 Hz. I used a 555 ic because works with low voltages like those of a li-ion battery.
I used the following materials:
- ne555 smd
- 1 10k resistor 0603
- 1 10uF 6.3v capacitor
- 5 red led 0805 smd
- 5 220 resistor 0805
- 1 old battery from smartphone
- 1 small pcb 1x2.4 in
Step 3: Make the PCB and Connect Wires
I had never made a circuit with smd components, first soldered the LEDs and their resistors and then the ne555 ic, the 10k resistor and the 10uf capacitor.
Finally, solder wire to the pcb.
Step 4: Solder Connectors and Works?
solder some connectors to the wires of the battery and the pcb.
just need to close the circuit, will it work?
Step 5: It Works!
it works! :D
Step 6: Install in the Seat
just remain install all it, the pcb and the battery.
the pcb hold it at pressure by the retroreflector.
the battery is hold it with 2 zip ties to the back of the seat
Step 7: All Done!
the led light finished and running in the bicycle.
Step 8: Final Note
I did not use any switch so when I do not use it, I disconnect. But it would be a good idea to place a switch to avoid connecting it backwards and damaging it.
The pcb in principle I did it with a marker, but then I made a pcb in eagle that is seen in step 2, here is
Participated in the
LED Contest 2017