Thursday, January 17, 2013

LiPo powered Arduino Esplora Game Platform

The Arduino Esplora plus Display handheld gaming device gets a portable power supply in the form of an Adafruit LiPo battery, charger, and Mintyboost to power up to 5 volts.
A nice flat LiPo battery powers the Esplora in this version
In my last post, the Arduino Esplora was mated with an Adafruit 1.8" TFT color LCD display and a ball-level bounce game by R0d0t made the Esplora a portable gaming device.  Sort-of.  As stated, the Esplora power cord was cut using an Energizer cell phone battery eliminator, a bulky, non-ideal solution.
The previous battery into the USB port was a stopgap
Researching how to power the Esplora in an elegant way, I found the Adafruit LiPo battery and charger board.  This solution will only power out 3.6 volts or so.  The Esplora is a 5 volt board so we need a way to boost the voltage.  Not easily done.  Adafruit also has their Mintyboost which boosts 3 volts to 5 volts for USB devices.  Perfect.  The combination of the LiPoly battery, charge board, and Montyboost gives the Esplora a relatively flat battery capability.  When I completed the mounting, I wished to power the board via the Tinkerkit connector instead of the USB port (it frees the USB for programming and provides a slimmer profile for gaming).  Triple-checking the polarity, I placed the 5 volts from the Mintyboost into the positive and negative terminals (observe polarity!) and it worked fine.
The battery is mounted and non-conductive foam placed on the Esplora back
The components are mounted on the Esplora via non-conductive foam to separate the PC board contacts to prevent unintended contact.  The connectors up top are standard 3 pin Molex connectors like the ones often used on PC fans.  Sparkfun also carries these.  The pinout of each looking below is (left to right): +5 volts, signal, ground.
The finished Esplora+Display Game obtains power via the left Tinkerkit  "output".
The Tinkerkit output pins are Digital 3 and 11 which we use for send and receive to a wireless radio.
The XBee is wired to the signal lines fron the two Orange Tinkerkit connectors.  These map to digital pins 3 and 11.  These pins can communicate with the radio via the Arduino Software Serial library.  This frees the display header pins to control, er, a display.  Those pins are the only free pins (the two white Tinkerkit connectors are inputs and are multiplexed into the Esplora so using them via a standard Arduino library is near impossible).
The red Sparkfun XBee Regulated can take nearly any radio that has a "Bee" pinout
You will see a socket between the LiPo battery and the power boards.  This is a Sparkfun XBee Explorer Regulated board which will power a radio in the XBee pinout via 5 volts and ensure the 5 volt signals of the Arduino will not harm a radio expecting 3.3 volt signals.

I have four types of radios - the XBee series 1 and 2 (Zigbee), a bluetooth radio in Bee pinout and a Sparkfun WiFly wi-fi radio also in Bee pinout.  This makes connecting the Esplora via radio a matter of plugging in the desired radio.

The only thing now would be a custom case, probably via 3D printing but I rely on my readers to discuss this as I do not have a printer and making one to the Esplora front and the battery back would be quite a task.  Possibly if it could be 3D scanned then input to a printer it would work.