This Tech Arts development kit is compact and has relatively meager power requirements for a microcontroller board running at 24 MHz. In addition, the devkit uses a LM1086 Adjustable LDO Voltage Regulator and provides a jumper (JB1) to conveniently switch between 3.3V and 5.0V operation. I loaded up the basic "helloworld" example from Part 1, and measured the power consumption at both voltages with and without a serial cable connected:
- 3.3V, 16.7mA w/o serial port
- 3.3V, 68.0mA w/ serial port
- 5.0V, 17.6mA w/o serial port
- 5.0V, 76.2mA w/ serial port
Left/Top: 5.0V operation (JB1 open), Right/Bottom: 3.3V operation (JB1 closed)
While hacking code in the lab, using a wall-wart is fine, however, the low power requirements of this devkit give you a variety of options when taking your project on the road. I've powered my board using the following:
A standard AA battery pack provides around 6800 mAh - 12,000 mAh of battery life.
A generic 3.7V, 0.2W solar panel, which gives you a laaaarge number of mAh.
Remember to set jumper JB1!
Cell-phone battery packs are great sources of power. This is an
old Envoy 3.7V 900mAh Li-Ion cellphone battery pack I had lying around.
I use the Sparkfun MAX1555-based charger to recharge the battery pack.
The usual warnings about Lithium-based rechargables apply!!!