X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=TeleMetrum%2Findex.mdwn;h=9f8f09e69ce78bd0e3c0f11179da5ce29787c1ac;hb=a389d0d0562197a31e556553853707c8f8bc3feb;hp=04b543fd88f454b8363a691ea8d7bcadc101b03e;hpb=6fdcada095218ae4566ccff3bbc78af4e2ed83f0;p=web%2Faltusmetrum diff --git a/TeleMetrum/index.mdwn b/TeleMetrum/index.mdwn index 04b543f..9f8f09e 100644 --- a/TeleMetrum/index.mdwn +++ b/TeleMetrum/index.mdwn @@ -3,6 +3,8 @@ This is a recording dual-deploy altimeter for high power model rocketry with integrated telemetry link. + + @@ -26,7 +28,9 @@ Another friend at the same conference showed us a board he was working on 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 ## @@ -35,14 +39,14 @@ simplify things by building a new altimeter with integrated RF link! * 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 ### @@ -52,7 +56,9 @@ simplify things by building a new altimeter with integrated RF link! * 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 @@ -65,27 +71,96 @@ simplify things by building a new altimeter with integrated RF link! * 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) ## + +## [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 March 2009, the first two boards are loaded, and we're about to start -turning them on and testing things! +[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.