- Mon Mar 26, 2012 8:14 am
#141883
So this is weird. My Venus won't start under certain conditions. I'm not entirely sure why.
Don't know if anyone's smart enough to figure this out
I have a Venus638FLPX breakout board (GPS-11058).
When I plug the Venus into a mini breadboard (PRT-08800) and connect up a 3.3V FTDI breakout board (BOB-00718) the Venus LED lights up briefly then goes solid after a brief interval and the GPS works. But....
When mounted to a home etched carrier board (below) the led lights briefly, then nothing.
The carrier board uses a cut down 28-dip socket. The Venus has standard 0.1" pin headers, gold plated.
Also, when I connect the mini breadboard to my mbed baseboard (also home etched) which breaks out UART TX/RX plus 3V3/GND, the Venus won't work if the mbed is powered by USB but will work if I power it off my 2400mAH 2S LiPo. Finally, after wiring Vcc, GND, RX, TX wires directly onto the Venus breakout, and connecting to mbed baseboard, Venus does work ok from USB-derived power.
Possible causes
[*] Flux residue: cleaned the carrier board with acetone, no help. Baseboard was cleaned too
[*] Solder bridge: doesn't explain non-working USB+mbed baseboard. I've inspected visually and with DMM, board checks ok
[*] Carrier board Vcc trace too thin (see line above): I spliced in a 24ga wire, no dice. Added solder blobs to ground, no dice.
[*] Supply path resistance too high, voltage drops too low (datasheet says min voltage 2.?? V), assuming massive startup current spike
Curious to see if anyone can figure this out.
I need to mount this thing to my mini AGV asap... I'd much rather have a tidy carrier board but for now I'll mount with mini breadboard and hot glue on the wires until I or someone can figure out what is going on.
Thanks in advance,
Michael
Don't know if anyone's smart enough to figure this out
I have a Venus638FLPX breakout board (GPS-11058).
When I plug the Venus into a mini breadboard (PRT-08800) and connect up a 3.3V FTDI breakout board (BOB-00718) the Venus LED lights up briefly then goes solid after a brief interval and the GPS works. But....
When mounted to a home etched carrier board (below) the led lights briefly, then nothing.
The carrier board uses a cut down 28-dip socket. The Venus has standard 0.1" pin headers, gold plated.
Also, when I connect the mini breadboard to my mbed baseboard (also home etched) which breaks out UART TX/RX plus 3V3/GND, the Venus won't work if the mbed is powered by USB but will work if I power it off my 2400mAH 2S LiPo. Finally, after wiring Vcc, GND, RX, TX wires directly onto the Venus breakout, and connecting to mbed baseboard, Venus does work ok from USB-derived power.
Possible causes
[*] Flux residue: cleaned the carrier board with acetone, no help. Baseboard was cleaned too
[*] Solder bridge: doesn't explain non-working USB+mbed baseboard. I've inspected visually and with DMM, board checks ok
[*] Carrier board Vcc trace too thin (see line above): I spliced in a 24ga wire, no dice. Added solder blobs to ground, no dice.
[*] Supply path resistance too high, voltage drops too low (datasheet says min voltage 2.?? V), assuming massive startup current spike
Curious to see if anyone can figure this out.
I need to mount this thing to my mini AGV asap... I'd much rather have a tidy carrier board but for now I'll mount with mini breadboard and hot glue on the wires until I or someone can figure out what is going on.
Thanks in advance,
Michael