Ultra PicoKeyer
27 January 2017 (Firmware V2.2)
Page 6 of 21
Battery and External Power
Note that your Ultra PicoKeyer does not have a power switch! The microprocessor “brain” of the keyer will go
into a low-current sleep mode after about a second or so with no inputs from either paddle or any of the buttons. In
sleep mode, the keyer chip draws so little current – a few microamperes -- that the internal battery can last for
years. As soon as you touch a paddle, the chip instantly “wakes up” and continues its normal operation. You won’t
be able to tell the difference when the keyer goes to sleep; the transition from power-saving sleep to operating is
instantaneous and requires no action from you.
The battery in your Ultra PicoKeyer should last for a long time – anywhere from several months to several years.
Battery life depends on a few factors:
Frequency of use. Obviously, the more you use the keyer, the shorter the battery life will be. Even with
regular use, you shouldn’t have to replace the battery more than once a year or so.
Sidetone. The sidetone speaker draws more power than the rest of the keyer functions. Using the sidetone
speaker will reduce battery life – but you should still only have to replace it once in a great while.
Beacon mode. The keyer does not sleep between messages while in beacon mode. If you use your
PicoKeyer to control a beacon full time, you should use an external power source. This can be as simple as
a pair of series AA or AAA alkaline cells. Remember to remove the coin cell before connecting an
external power source, and never allow the external source to exceed 3.3 V – and of course, double-check
the polarity before applying power!
Battery replacement is straightforward – just remove the two screws from the cabinet bottom, remove the keyer
circuit board from the cabinet, slide the coin cell battery out of its holder and install the new battery. All of your
settings and messages will be retained even with no battery power.
If you should need to replace the battery in your keyer, you will need a CR2032 or equivalent lithium cell. These
are very common and are used in many devices from garage door openers to car remotes to thermometers and
medical monitors. You can order high quality CR2032 cells from
. Don’t use any battery
or power source that exceeds 3.3 volts.
Straight Key Mode
The Ultra PicoKeyer can detect and use a properly wired straight key. During its power-on program, the PicoKeyer
checks to see if either paddle input is grounded. If one input is shorted, the other input is assumed to be a straight
key. This way you can plug in a straight key wired to a mono plug and use it without any changes or adjustments.
Be aware that while the setup menu will still function and you can send messages, you will not be able to record
messages while using a straight key.
Of course it’s not always convenient to pull out the battery when you switch between a paddle and a straight key.
To detect paddles or a straight key, just press buttons 2 and 3 (the middle two) at the same time. It will
automatically re-scan the paddle inputs and determine whether or not a straight key is plugged in (you will hear “P”
if a paddle or no key is detected, or “K” if a straight key is detected). If you use a straight key with a stereo plug,
you may find it more convenient to switch between paddles and a straight key using the
K
menu setting.
Sidetone
The PicoKeyer’s sidetone is a square wave audio signal generated by the microprocessor. Sidetone can be turned
on or off, and the audio frequency can be changed from the setup menu. There is a very noticeable peak in the
response of the on-board speaker at roughly 2 kHz; if your PicoKeyer is installed in the plastic cabinet you’ll
