Maker Pro
Maker Pro

bike light riddle

I have a bicycle light, Opticube, standard unit,
single button, uses 2 AA batteries.

operation:
1. Push button, light on.
2. Push again, hold 2 seconds, off.

or:
1. Push button, light on.
2. Push again, blinking mode.
3. Push again, hold 2 seconds, off.

But when the batteries are low, the
'hold, then off' time lengthens to 5 seconds.

What's the timing circuit?
 
J

Jasen Betts

Jan 1, 1970
0
I have a bicycle light, Opticube, standard unit,
single button, uses 2 AA batteries.

operation:
1. Push button, light on.
2. Push again, hold 2 seconds, off.

or:
1. Push button, light on.
2. Push again, blinking mode.
3. Push again, hold 2 seconds, off.

But when the batteries are low, the
'hold, then off' time lengthens to 5 seconds.

What's the timing circuit?

pronbably a 4 bit microcontroller.
 
M

Michael Black

Jan 1, 1970
0
pronbably a 4 bit microcontroller.
I thought he was asking about why he had to hold the button down longer
when the batteries are getting weak.

Michael
 
Could be.
But I thought a microprocessor, with its support
components, would be overkill, too costly, for a
cheap consumer item. Especially with such simple function.

I thought he was asking about why he had to hold the button
down longer when the batteries are getting weak.

Both.
 
J

Jasen Betts

Jan 1, 1970
0
Could be.
But I thought a microprocessor, with its support
components, would be overkill, too costly, for a
cheap consumer item. Especially with such simple function.

there's plenty of microcontrollers that'll run on anything between 1.8
and 3.3V and need no external parts, eg: ATTINY4-TSHR or
PIC10LF320-I/OT under a buck in small quantities, much cheaper in lots
of 100000 as bare dice for chip-on-board construction.
I thought he was asking about why he had to hold the button
down longer when the batteries are getting weak.

"what's the timing circuit"

It's a microcontroller, the clock is probably the on-chip RC clock,
it's slower to turn off possibly because the designer intends that
behaviour as a warning that the batteries are low. it's better (and
easier) to warn of low batteries at turn-off
 
there's plenty of microcontrollers that'll run on anything
between 1.8 and 3.3V and need no external parts, eg: ATTINY4-TSHR
or PIC10LF320-I/OT under a buck in small quantities, much cheaper
in lots of 100000 as bare dice


It's a microcontroller, the clock is probably the on-chip
RC clock, it's slower to turn off possibly because the
designer intends that behaviour as a warning that the batteries
are low. it's better (and easier) to warn of low batteries at turn-off

Deliberately? Possible, but seems odd.

These chips require no external oscillator?
How does it know the battery is low?

It will drive a FET switch (for the bulb) without
a buffer? What are the minimum necessary external
components?
 
M

Michael Black

Jan 1, 1970
0
Deliberately? Possible, but seems odd.

These chips require no external oscillator?
How does it know the battery is low?

It will drive a FET switch (for the bulb) without
a buffer? What are the minimum necessary external
components?
Chances are good that it may be some dedicated IC in there. If someone an
cook up enough demand, it's simpler for a dedicated IC than everyone
working on their own.

I have some single LED "bicycle lights" that are smaller than a 9v battery
and you attach to the handlebars with the included elastic. They cost
$3.75 Canadian. The first one I bought, it had slow flash, fast flash and
steady on, you'd press the button and advance the mode, then another press
ona off. The mroe recent ones do away with one of the flash modes, so
it's only continuously on or flashing. At that price, you can't spend
much time adding parts to a circuit board, so chances are good it's
dedicated to it. For all I know, it may be what's used in the bigger LED
bike lights, which of course have a similar ability to flash and stay on,
and use the on/off button for the same function.

So if it's a dedicated IC, chances are good as much as possible goes in
the actual IC (which would just be an expoxy blob).


Michael
 
K

Kevin McMurtrie

Jan 1, 1970
0
I have a bicycle light, Opticube, standard unit,
single button, uses 2 AA batteries.

operation:
1. Push button, light on.
2. Push again, hold 2 seconds, off.

or:
1. Push button, light on.
2. Push again, blinking mode.
3. Push again, hold 2 seconds, off.

But when the batteries are low, the
'hold, then off' time lengthens to 5 seconds.

What's the timing circuit?

The controller clock might be driven from the switching power supply
signal, either intentionally or not.
 
Top