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circuit easily as well. You will need a suitable battery to power the Eggtimer (two AAA
batteries work well if you chose the "3V" option, and a 9V battery works fine if you are using
the regulator) and optionally a separate battery for deployment testing (a 9v battery works
fine).
IMPORTANT: You MUST match your choice of battery to the voltage option that you chose
when you assembled your kit. If you chose the "3V" option WITHOUT the regulator, the
Eggtimer is designed to be connected directly to a 3V-4V battery, such as two "AAA"
batteries, a 3.7V 1C LiPo battery, a 3V lithium battery such as a CR123 or CR5, or a 3.6v
NiMH battery pack. It will NOT work with a 9V battery. If you configured your Eggtimer's
power jumpers for 3V and connect the Eggtimer to a 9V battery, you WILL damage it
irreparably. If you are using a variable-voltage power supply for testing, make SURE that
you are using a suitable voltage. Damage due to high voltage is not covered by the Eggtimer's
Limited Warranty. If you chose the "9V" option using the regulator, you can use any power
supply from 4.5V all the way up to 30V. A 9V battery or a 2S LiPo battery is ideal.
You will need to use an USB-TTL interface cable, conveniently the Eggtimer comes with one.
The header is pinned for a standard FTDI-type 6-pin connector, but you can also use a cable
with individual pins (TX, RX, GND) by simply plugging those pins into the corresponding pin
on the connector. You will need to install the driver software for the USB-TTL interface that
you are using on your computer before you can use it. The one that comes with the Eggtimer
uses a Prolific PL2303TA USB-serial chip, your operating system may already have the
drivers installed for it but if it does not you can get it at
http://www.prolific.com.tw/US/ShowProduct.aspx?pcid=41&showlevel=0041-0041
They have drivers for Windows (x86 and x64 versions), MacOS, and Linux. Since the
Eggtimer uses a serial terminal interface, this means that you can use just about any computer
you want with it. See the Eggtimer Users Manual for suggestions on suitable terminal
software, many of them are freeware.
The USB-Serial cable that comes with the Eggtimer has three separate wires rather than a 6-pin
FTDI-standard header. You need to connect it to the Eggtimer as follows, depending on the
colors of your cable's pins (we have several suppliers and the colors are unfortunately not
standardized.
Black – Green – White Cable:
BLACK - Eggtimer "GND" pin
GREEN – Eggtimer "RX" pin
White – Eggtimer "TX" pin
Plug the serial interface into a USB port, and confirm that your OS assigns a serial port to it.
Set the serial port to 19,200 baud, 8 bits, 1 stop bit, no parity, and no handshaking. Open up
your terminal program, select the serial port that your OS assigned to the USB interface, and
connect. Connect power to the Eggtimer, after a few seconds the IND light should come on, it
should start beeping, and you should see the programming screen:
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