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DATASHEET

Technical details for those technically inclined.

DIMENSIONS



Total weight is 34 grams.
Four 4-40 screw holes make mounting onto your robot easy.

DOCUMENTS


Axon schematic
ATmega640 Datasheet
USB to UART Bridge Datasheet and App notes
Axon printout (a 1:1 ratio printout of the Axon)
ATmega640 pinout quick reference

VOLTAGE TOLERANCES

The Axon is designed to be fully functional from a single battery source, although you can easily plug in additional parallel batteries to the power bus.

Absolute minimum required voltage is 5.35V, while the recommended battery voltage is 6V to 7.2V. Maximum voltage at 20V, however most servos cannot handle above 7.2V before being damaged.

There are two power buses. ADC pins 0 to 15 are regulated at 5V, while all other pins are directly connected to your battery. There is also a 3.3V output pin (see current tolerances).

The Axon has polarity protection features, meaning that it is designed to protect itself if you accidentally plug your battery in reverse. However, it will NOT protect any external component connected to the unregulated battery bus.

This is how the pins are set up in terms of power and signal. Refer to your Axon board for pin numbers.



Pins	Voltage
E2-E7	battery
H2-H6	battery
Bat	battery (input)
A0-A7	battery
J6	battery
C0-C7	battery
0-15	5V regulated
3.3V	3.3V (output)
G	ground
+	battery
-	ground



CURRENT TOLERANCES

All ADC power bus pins get power from the 5V LDO voltage regulator with maximum allowable current of 1.5A. Adding a heat sink to the regulator can raise this amount depending on various environmental factors. See the FAQ for more on heat sinks.

The Axon has been tested to handle at least 5A on each power bus, but can in theory handle ~13A. Placing your high current draw components near the battery can up this number. This limitation is entirely based on power bus tracing thickness, meaning that if you require higher currents you must make your own separate power bus.

Individual I/O pins can supply about ~20mA power, each. Exceeding this number could damage the I/O pin.

The Axon also has a special regulated 3.3V output connector if you have any components or sensors that require this voltage. This pin cannot supply more than about 73mA, or 90mA if you aren't using USB. If you find that USB becomes unstable or fails to work when using this output, make sure you aren't overdrawing current and place a 4.7mF tantalum capacitor (polarized) between 3.3V and ground.

You must also keep in mind the current tolerances of the included Hitec 572125S on/off switch. These are the limits they quoted it at:
"A conservative estimate would be in the 10 amp range for the 572125S and 16 amp range for the 54407S. But again these are just estimates."
- Hitec Sales Manager

NOISE SUPPRESSION

All electronics creates electronic noise and sudden voltage spikes/drops that can potential cause problems. The Axon has been intentionally designed to minimize this noise, and in fact during extensive tests I found no detectable (non-negligible) noise. However, your needs may be different. If you find you are using highly sensitive sensors, I recommended attaching additional noise suppression ceramic capacitors in parallel to the regulated power bus.

CAD FILES

Feel free to contact me if you would like to share your CAD files for the Axon.

Axon: AutoDesk Inventor CAD Files (612kb)

Axon: Google Sketch CAD
if that link Sketchup link ever fails, download a hardcopy directly (4.2mb)

If you'd like to create your own CAD, feel free to download the Axon texture images.

If you have a SolidWorks design of the Axon, let me know!