I am considering a simple, low cost logging dongle for use in harsh environments:
HW
- uProc with UART
- RS-232 transceiver (max232)
- USB and Serial connectors
- regulator
- 1Mbyte SPI flash
- Marcell recommends MMC. In an epoxy-potted case it can be soldered without a socket.
Software
- Identify VEMS when attached and issue data dump requests - log resulting data stream
- Accepts commands when connected to host (PC or PDA) to dump data
- On board USB rechargable coin cell or host powered (5V on VEMS DB9 or USB on PC/PDA)
Conclusion
BoM, board, assembly and testing = cheap
Firmware = easy
Podded in epoxy for ruggedness
Anyone interested, please chime in. Cost for members should be kept in the $20 range.
Notes
- The group effort has (long-pending) plans on the following:
- firmware support for v3.x MMC logging GenBoard/LoggerIntegration is a bit confusing. See GenBoard/LoggerIntegration/MMC
- arm-boost is the codename of the low-cost (no fancy connectors) potted board (under development; 90 ARM uC-s are ordered for it and come in 2006 March) that is mostly sensing / networking / logging (but very restricted when it comes to power outputs). Useful for surprisingly many applications, logging is one. I suggest you join the development - first the MMC firmware _code_ than this.
- It's possible to roll an even smaller board (than arm-boost, perhaps with a different uC to save another $1 with only $900 of development task) but probably only justified if >500 can be sold.