# TeleMetrum
This is a recording dual-deploy altimeter for high power model rocketry
-with integrated telemetry link.
+with integrated GPS and telemetry link.
-<a href="rawfront.jpg"> <img src="rawfront-thumb.jpg"></a>
-<a href="rawback.jpg"> <img src="rawback-thumb.jpg"></a>
+These are photos of our current version,
+which includes an integrated GPS receiver and patch antenna:
+
+<a href="v0.2/cimg5164-cropped.jpg"> <img src="v0.2/cimg5164-thumb.jpg"></a>
+<a href="v0.2/cimg5171-cropped.jpg"> <img src="v0.2/cimg5171-thumb.jpg"></a>
+
+And this is a photo of our original board with serial port for off-board GPS,
+without the big off-board 1000uF cap from the original ejection circuit:
+
+<a href="v0.1/loadedpair.jpg"> <img src="v0.1/loadedpair-thumb.jpg"></a>
## Motivation ##
using a different part in the same TI series, that integrated a transceiver
and CPU on the same chip.
It didn't take us long to realize that with such a part we could combine and
-simplify things by building a new altimeter with integrated RF link!
+simplify things by building a new altimeter with integrated RF link! And
+after gaining some experience in 2009 with a first version, we realized we
+always want GPS on board, which lead to our current second generation boards.
## Features ##
* 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://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](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) ##
-* The CC1111F32 is a 36-pin QFN package, which necessitates reflow soldering.
+## [Flight Logs](flightlogs) ##
-* 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!
+## Problems ##
+
+* 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!
+[git.gag.com](http://git.gag.com) in the project
+[hw/telemetrum](http://git.gag.com/?p=hw/telemetrum;a=summary).
+
+Work on the next version proceeds on the master branch, with occasional
+temporary branches created when Bdale is making some major / speculative
+change. The 'v0.2' and 'v0.1' branches document what we're actually flying
+right now on the two respective PCB revisions. The 'ground' branch has a
+cut-down schematic used to generate the BOM for partially loading v0.1 boards
+to used on the ground. We call the on-the-ground version 'TeleDongle'.
+
+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 from the v0.2 branch:
+ * [schematic](v0.2/telemetrum.pdf)
+ * [pcb artwork](v0.2/telemetrum.pcb.pdf)
+ * [bill of materials](v0.2/partslist.csv)
+* These are as of the working-v0.1 tag:
+ * [schematic](v0.1/telemetrum.pdf)
+ * [pcb artwork](v0.1/telemetrum.pcb.pdf)
+ * [bill of materials](v0.1/telemetrum.bom)
+
+We have firmware that works well enough that we now routinely allow TeleMetrum
+to control flights by firing ejection charges. We've flown v0.1 boards in
+rockets exceeding 50g acceleration, above Mach 1, and to altitudes greater
+than 12k feet AGL with great results. Keith wrote a ground station program
+called
+ao-view 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! We have post
+flight analysis software that makes it easy to extract data from the board,
+analyze it, and even generate KML files for viewing flights in GoogleEarth!
+More details on the software, including full source code and pre-built packages
+can be found on the [AltOS](../AltOS) page on this site.
+
+## 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 temperature sensor, since baro sensor is already compensated and there's a sensor on the cc1111
+* eliminate serial port connector
+* integrate SkyTraq Venus GPS receiver and patch antenna on-board
+* change debug connector to 4 pin Tyco MicroMaTch
+* add 8 pin Tyco MicroMaTch connector for companion board interface
+* use v_lipo as pyro power, eliminating the huge 1000uF capacitor and instead
+ adding ballast capacitance on the 3.3V rail to prevent brownouts
+* move all connectors, beeper, and GPS patch antenna to the "other side" of the board from the surface mount parts
+* add a rectangle of silk screen material for improved serial number labeling
+
+As of early December 2009, the layout work for v0.2 is done and we're busy
+verifying it and deciding exactly how we're going to build them. We hope to
+have first prototypes to test in time to show the new version at LCA in late
+January 2010. If it works out as well as we hope, v0.2 may be made available
+in assembled and tested form to others in the rocketry hobby who have
+expressed interest sometime in 2010.
projects / web / altusmetrum / blobdiff