Lassen IQ Breakout PCB

Introduction

The lassen IQ is a great GPS for ballooning, relatively cheap (£20-£30) and is known to work above 18km altitude. There are 2 problems with the module, firstly it doesn't have great sensitivity (unlike a ublox for example) and also it has a tiny connector on the base! I therefore designed a pcb to breakout the lines from the tiny connector to nice 0.1” and also added a backup battery (coin cell) to allow for warm rather then cold starts. I got 5 boards made by Seeedstudio for $30 (and an additional $12 rebate once i open source the design), the quality is excellent though they do take quite a while to get from Hong Kong (probably not helped by the postal strike).

Schematic

Pinout

RXAHEADER

  1. VCC
  2. TXA (TSIP)
  3. RXA
  4. PPS
  5. GND

RXBHEADER

  1. VCC (Top pin)
  2. TXB (NMEA)
  3. RXB
  4. GND
  • To use TXB/RXB you need to put a 1K resistor in on the RXBPULLUP, to use TXA/TXB on the RXAPULLUP
  • To connect the lassen to the board a smd connector is required Toby

Final Board

GPS Antenna

  • For this flight I'm using the Antenna GPS Ultra-Compact Embedded HFL for Lassen IQ. Its nice and small with quite a short antenna cable. The antenna is greatly improved with the addition of a ground plane, this just needs to be a bit of metal connected to the base. With this in place the time to a fix is a lot shorter. I found a bit of scrap metal and soldered it to the base.
 
missions/ballasthalo/lassenbreakout.txt · Last modified: 2009/11/29 09:23 by jamescoxon
 
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