This is a recording dual-deploy altimeter for high power model rocketry
with integrated telemetry link.
+<a href="loadedpair.jpg"> <img src="loadedpair-thumb.jpg"></a>
<a href="rawfront.jpg"> <img src="rawfront-thumb.jpg"></a>
<a href="rawback.jpg"> <img src="rawback-thumb.jpg"></a>
* Recording altimeter for model rocketry
* Supports dual deployment (can fire 2 ejection charges)
* 70cm ham-band transceiver for telemetry downlink
-* Primary operations based on pressure sensor
+* Barometric pressure sensor good to 45k feet MSL
* Temperature sensor
* 1-axis high-g accelerometer for motor characterization
* On-board non-volatile memory for flight data storage
* Serial port for attachment of GPS module
* USB for power, configuration, and data recovery
* Integrated support for LiPo rechargeable batteries
-* Designed to fit 29mm airframe coupler tube
+* 2.5 x 1 inch board designed to fit inside 29mm airframe coupler tube
### Developer View ###
* 32k Flash
* 4k RAM
* USB 2.0
- * analog, digital, and serial I/O
+ * 6 12-bit analog inputs (11 bits with single-ended sensors)
+ * 2 channels of serial I/O
+ * digital I/O
* [Microchip 25LC1024](http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en520389) CMOS serial EEPROM
* 128k x 8
* SPI interface
* Runs from on-chip flash, uses on-chip RAM, stores flight data to
serial EEPROM chip
* USB serial emulation for "console" interface
- * USB mass storage emulation for data recovery
* Tools Used
- * [gEDA](http://geda.seul.org/) for schematic capture and PCB layout
+ * [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
* [SDCC](http://sdcc.sourceforge.net/) compiler and source debugger
- * [FreeRTOS](http://www.freertos.org/) kernel
* Licenses
- * The hardware is licensed under the TAPR [Open Hardware License](http://www.tapr.org/ohl.html)
+ * 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 ##
+## [Production History](production) ##
+
+## [Flight Logs](flightlogs) ##
-* The CC1111F32 is a 36-pin QFN package, which necessitates reflow soldering.
+## Problems ##
-* Since we needed to reflow solder anyway, and because TI used them in their
- reference design, we went a little crazy and used 0402 passive parts
- everywhere. That means working under a microscope to place parts!
+* The CC1111F32 is a 36-pin QFN package, which necessitates reflow
+ soldering. Since we needed to reflow solder anyway, and because TI used
+ them in their reference design, we went a little crazy and used 0402
+ passive parts everywhere. That means working under a microscope to
+ place parts! Without an inspection microscope, loading and testing these
+ boards might be impossible.
+
+* The v0.1 artwork has the USB connector footprint placed wrong, so that the
+ connector hangs out over the edge of the board instead of being flush with
+ the edge.
+
+* The v0.1 artwork has two issues that require cuts and jumps. The first is
+ that we need chip select on the SPI memory. To fix that, we give up the
+ ability to put the accelerometer into self-test mode and use that GPIO line
+ to pull chip select on the memory. The second is that the igniter sense
+ circuits each need a second resistor to complete the voltage divider so our
+ 3.3V CPU ADC can read the 5V ejection voltage. This is fixed by changing
+ two resistor values, and tacking two additional resistors onto the board
+ with jumpers to ground.
## Artifacts ##
The hardware design current gEDA files are available from
-[git.gag.com](http://git.gag.com).
-
-As of 6 January 2009, the raw boards are here, so we're nearly ready to try
-building our first prototype! Stay tuned for updates, and note that
-Bdale will be giving an update in his session at Linux Conference Australia
-in late January...
-
+[git.gag.com](http://git.gag.com) in the project
+[hw/telemetrum](http://git.gag.com/?p=hw/telemetrum;a=summary).
+
+The 'working-v0.1' tag on the master branch indicates what we're actually
+flying right now. The v0.1 PCB artwork, and schematic updated to include
+the parts Bdale loads for a functional board including the two cuts and jumps
+and two added resistors plus ground leads required as rework. The 'nextcut'
+branch is work towards our next PCB revision. The 'ground' branch has a
+cut-down schematic used to generate the BOM for partially loading boards
+to use in the matching [TeleTerra](../TeleTerra) ground station design.
+
+For those who don't have ready access to the gEDA suite, here are pdf snapshots
+of files in more easily readable form. These are all as of the working-v0.1
+tag:
+
+* [schematic](telemetrum.pdf)
+* [pcb artwork](telemetrum.pcb.pdf)
+* [bill of materials](telemetrum.bom)
+
+
+We have firmware that is working well enough that we're starting to allow
+TeleMetrum to fire ejection charges. Keith has also written a ground station
+program called aoview that logs telemetry to disk, displays current and max
+values for key parameters during flight, and even includes voice synthesis
+during the flight so that our eyes can stay on the rockets! The source to all
+this is available from [git.gag.com](http://git.gag.com) in the project
+[fw/altos](http://git.gag.com/?p=fw/altos;a=summary). This repository includes
+sources for the firmware, ground station program, and related utilities. Note
+that actually building these sources requires a modifified version of sdcc,
+for which we have not published diffs since they are in the process of being
+accepted upstream. Watch this space for more details.
+
+## Future Plans ##
+
+Work is underway on a second revision of TeleMetrum with the following changes:
+
+* stretch board length by 0.25 inches
+* adjust USB connector position to be flush with edge of board
+* eliminate beeper
+* eliminate temperature sensor, since baro sensor is already compensated and there's a sensor on the cc1111
+* eliminate serial port connector
+* integrate MN5010HS GPS receiver and chip antenna on-board
+* change debug connector to 4 pin 1.25mm connector as was used for serial port
+* add 7 pin 1.25mm connector for companion board interface
+* use v_lipo as pyro power, eliminating the huge 1000uF capacitor and instead
+ adding ballast capacitors on the 3.3V rail to prevent brownouts
+* add a rectangle of silk screen material for improved serial number labeling
+
+We hope to build and fly prototypes of this version in late 2009. If it works
+out as well as we hope, this version may be made available in assembled and
+tested form to others in the rocketry hobby who have expressed interest.
projects / web / altusmetrum / blobdiff