Shetland Attack Pony. Copyright 2005 Phil!


Chips required...

Function		Id		Proto Pack	Final pack

Magnetoresistive Z	HMC1001		SIP???		SIP - fine wire spacing...
Magnetoresistive XY	HMC1002		SO-20 (296mil)  SO-20 (296 mil)
?xAccelerometer		LIS3LO2AS4	SO-24 (296mil)	SO-24 (296 mil)
xUSB charger		MAX1811		SO-8  (150mil)	SO-8  (150 mil)
xLi-ion protection	DS2764		TSSOP16		TSSOP16 #do not interfere with charger...
LED Display		HCMS3962	DIP12W		DIP12W
xUSB UART		FT232R		module		SSOP28
xMicrocontroller	PIC16F687	DIP20		DIP20




Prototyping - look on e-bay, and get some stuff internationall from china... probably cheapest way...

Sensor choices

Honeywell Magnetoresistive Sensors

HMC1001 216-6297
HMC1002 216-6304

Accelerometers - try digikeys one...
LIS3L02AS4 497-4128-5-ND

Also try digikey for laser modules... - actually just get a laser pointer and break it; use a 3V reg as well...


Battery - RCR123A - LI-ion rechargable 600mAH 16x16x33mm 

Management chips
MAX1811 - charger and USB power detector...
DS2764 - battery protector and fuel gauge...

needs some MOSFETs

USB - UART = FT232BM - seems like a good bet...



PIC requirements...
16F687 - 18 IO pins, USART, SPI, 12x10-bit ADCs - should be enough
Use SPI to drive LED driver - should work fine... and saves me having to program it...
6 analog ins for each sensor



EUART		For USB serial connector needs 2 ports - Tx and Rx.
Just make sure that we can keep up...

may be able to multiplex these over the LED driver ports as well...


MagSense Calibrate  - to reset the offset values for current env.
         Also turn on self test mode in the acceleromete

CHG_EN		} MAX1811

USB_OK		}
USB_IN		} FT232
USB_OUT		}

CALIBRATE	} Sensors
Gx		}
Gy		}
Gz		}
Mx		}
My		}
Mz		}

Clock		}
Data		} LED Driver, HCMS 3962 496-5282
Reg Select	}
Chip enable	}
RESET           }

SPI_CLK		} DS2764
SPI_D		}

LASER		} LASER modulator

Power in

Ground

19 pins reqd. Toss. Possibly 20 if add in an eeprom... mutter
21 if add in clever control over Max722 stuff for reset.

Options...

Connect USB_OK and CHG_EN directly together; just use a transistor and pull-down resistor...
	- saves 2 pins

Use LED Driver chip enable to limit data in/out on DS2764
	- saves 2 pins

Combine RESET and Calibrate functions
	- saves 1 pin