The mode button is also mounted externally by wiring
a second SPST momentary switch at the end of the vent.
This makes it much easier to change modes while riding.
For those of you who would like a less permanent
installation or would like to have the option of moving the
light from helmet to helmet, you can easily mount the
circuit board, battery, and LEDs in a small box as shown in
Photo 7. The DS18B20 is in the lid just left of center, and
the yellow and orange wires go to an externally mounted
mode button. You will also note that the positive lead
from the circuit board goes directly to the metal case as
do the anodes from the six LEDs. This simplifies wiring as
the only leads that come back from the LEDs to the circuit
board are those from the cathodes. The SPDT toggle
switch turns the unit on and off. When the switch is off,
the rechargeable battery connects to a charging plug
(hidden from view in the photo) so that you cannot
inadvertently apply charging voltage to the circuit.
The next revision of the circuit board will control each
of the two MOSFETs with a separate pin on the PIC. This
will allow independent control of the front and back LEDs.
This would allow a mode, for example, that would leave
the back red LEDs flashing while the front white LEDs
could be on constantly so that you could read a map or
perform repairs. I’m sure that additional modes of
operation will come to mind, as well.
I am also considering — at the request of a non-cycling friend — making a solar powered unit with only
one LED. It will be placed in his garden to continuously
report the outdoor temperature. He reasons that it will
give a better outside reading that a thermometer close to
the house and he will be able to read it without putting on
I have made a number of Bike Blinker +Plus+ units for
personal use and for friends. I encourage you to do the
same. I think you will find that it can add to your visibility
and may provide some fun, as well.
Try this: Leave your helmet flashing on the bike when
you go into the local coffee shop. Invariably, someone will
tell you that you forgot to turn the light off. Watching their
reaction as you relate how it is giving you temperature
reports is an added benefit that is sure to make
you smile! NV
A complete kit to go with this article can be
purchased online from the Nuts & Volts Webstore
at www.nutsvolts.com or
call our order desk at 800-783-4624.
■ PHOTO 7. Blinker in a box.
August 2010 37