# AltusMetrum
-<p>
+
This is the design that started it all! Bdale got frustrated with existing
commercial altimeters and decided to build his own. This project was
presented in talks at LCA, SCALE, OLS, and Debconf in 2008.
-</p>
-<p>
-Here are photos of the front and back sides of the version 0.1 prototype PCB.
-</p>
+
+Here are photos of the front and back sides of the version 0.1 prototype PCB,
+which was 100% auto-routed on 2 layers using the
+[gEDA](http://www.gpleda.org)
+schematic and pcb tools.
+
<a href="hpim2581.jpg"> <img src="hpim2581-thumb.jpg"></a>
<a href="hpim2582.jpg"> <img src="hpim2582-thumb.jpg"></a>
* NXP LPC-2148 Processor (ARM7TDMI-S)
* 512k Flash memory, 32k RAM
* USB plus lots of analog, digital, and serial I/O
+* Microchip 24FC1025 CMOS serial EEPROM
+ * 128k x 8
+ * I2C interface
+* Various Sensors
+ * Freescale MP3H6115A pressure sensor
+ * Freescale MMA7260QT 3-axis accelerometer
+ * Microchip MCP9700A temperature sensor
+ * (Honeywell 2-axis magnetic sensor left out of v0.1)
+* Software Features
+ * Written mostly in C with some ARM assembler
+ * Runs from on-chip flash, uses on-chip RAM, stores flight data to
+ serial EEPROM chip
+ * USB serial emulation for "console" interface
+ * Uses GCC, newlib, FreeRTOS, LPCUSB
+ * Based on a demo package written for the Olimex LPC-P2148 eval board
+ by J C Wren
+* Licenses
+ * The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
+ * The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
## Problems ##
## Artifacts ##
+The best version of Bdale's [Peace Love and Rockets](AltusMetrum.odp)
+presentation about this hardware generation was given at the Ohio LinuxFest
+2008. Note that there are many photos included, so this is a HUGE file!
+
The version 0.1 design had enough issues that Bdale decided not to publish
it. Work on an 0.2 revision is mostly complete at the schematic level, and
some printed circuit board artwork updates were made, but a second run of
boards was never attempted. This design is now mostly of historical interest.
+
+## Futures ##
+
+If we decide to do further work on this design, a number of changes seem
+potentially appropriate for the next board revision, in addition to just
+fixing bugs found in the turn-on of the initial boards.
+
+* The LiPo battery support from [TeleMetrum](../TeleMetrum) should be copied
+ into this design, replacing the battery screw terminals with a standard LiPo
+ 2-pin battery connector.
+
+* The [SparkFun](http://www.sparkfun.com) folks have produced
+ a [USB bootloader for the LPC2148](http://www.sparkfun.com/commerce/tutorial_info.php?tutorials_id=94). It
+ requires an SD card for temporary storage of code to be
+ flashed. Replacing the current external SPI memory chip with a microSD
+ socket could make sense. The socket size is under a cm square, and ones
+ that have a fold-up locking top are about $2, vs over $6 for the current
+ memory chip. The cards themselves are getting very cheap, too, and can
+ store much more data than the current 128k memory chip. This would require
+ moving ADC_Vbat to a different ADC input so that pins 27, 29, 30, and 31
+ would be available for the microSD socket.
+
+* Consideration should be given to changing the accelerometer for a higher-G
+ single axis unit as in [TeleMetrum](../TeleMetrum) if we want to be able to
+ use it for motor characterization.
projects / web / altusmetrum / blobdiff