Jeff's brain-dump for January 31, 2012

nerdkit

I'm currently borrowing IXR's nerdkit:
  • Atmel atmega168-20 microcontroller
  • breadboard that perfectly matches their instructions
  • 4 line 20 character LCD
  • USB to serial adapter cable (the prolific chip's in the USB plug)
  • LM34 temperature sensor and other parts


I found the perfect case for it
(can we prototype it? YES WE CAN!)

I put all the tech info on a USB flash drive in the kit

tackle box-o-parts

A friend uses ONLY these Plano tackle boxes for all his parts because
  • they're see-thru, sturdy and stack nicely
  • the partitions are adjustable
  • They are available in 2 depths.
  • They are sold in many stores: Lowe's, Home Depot, Sears, sportings goods
Be sure to choose ones with 3 hinges and real latches
(other brands have cheap flex-hinges that will eventually fatigue and break
or latches that don't hold tight or pop open)


What's in my parts box this week?
Mostly tiny modules and their connectors & wires.
  • The Bus Pirate open hardware tool for JTAG and other serial protocols.
  • 3: Xbee Zigbee modules
  • 1: Xbee adapter board
  • bluetooth adapter board
  • USB to TTL serial adapter
  • SD card adapter board

Teeny helpful PCB

These tiny boards help with breadboarding by giving complete circuits with surface mount chips.

The top one's a MAX-232 chip which converts between RS232 (the DB9 connector) and TTL levels.
The MAX232 series chips replace the vintage 1488 Quad Line Driver and the 1489 Quad Line Receiver chips (which require +12 and -12 volt power supplies) by integrating on-chip voltage boosters with the receivers AND transmitters.

The center one's the $14.75 Adafruit FTDI friend featuring the FTDI FT232RL chip that does all the work of converting USB to TTL serial.
A friend notes that the $12.99 Gravitech FT232RL USB to UART Breakout Board gives ALL the chip's signals as used by bit-bang mode for microcontroller programming.
[The Prolific technology PL-2303 USB to Serial Bridge Controller is nearly identical to the FTDI FT232RL chip, but lacks the on-chip EEPROM to save settings. Both are 28 Pin surface-mount SSOP package ]

The bottom one's a SD card socket with not much more.
A friend found others with better support and access to more signals:
SparkFun MicroSD shield
Gravitech SD/MCC adapter
Above the ruler: Travis Goodspeed's GoodFET:
an open-source JTAG adapter using the TI MSP430 and FT232RL chips.
It remains a bare board until I have access to proper surface mount soldering equipment.

Below the ruler: The Sandbox Electronics Bus Pirate which comes pre-assembled
with a set of clips and firmware & driver & software
for a variety of protocols: JTAG, SPI, I2C, MIDI and others.