I was able to successfully calibrate the TeleDongle with my specan so
now I'm back to the original issue of troubleshooting intermittent
telemetry from the TeleMetrum. I was finally able to duplicate the
problem when in Idle mode.
Here's what the altos debug window shows normally every few seconds:
s
RSSI: -32
set_radio_frequency 434.550 (freq true) (set true) 5696589
c F 434550
start remote 434.550
set_radio_frequency 434.550 (freq true) (set true) 5696589
c F 434550
c T 0
c c K5RLW
p
E 0
g
Date: 20/09/26
Time: 20:18:02
Lat/Lon: 0 0
Alt: -17
Flags: 0x20
Sats: 1 32 22
done
A
ADXL375 value 8 7 -23 self test
1392 min 1104 max 1537
B
Pressure: 6064364 97929
Temperature: 8438740 3063
Altitude: 286
a
tick: 8064 drogue: 806
main: 807 batt: 3379
stop remote
~
After letting it sit for a while in Idle mode (with my other 1W 900 MHz
transmitter on), it started to fail in the same way as I've seen. The
Age seems to make it up to around 20-22 before an update occurs. Here's
some of the debug output from altosui:
s
RSSI: 0
set_radio_frequency 434.550 (freq true) (set true) 5696589
c F 434550
start remote 434.550
set_radio_frequency 434.550 (freq true) (set true) 5696589
c F 434550
c T 0
c c K5RLW
p
E 0
g
A
B
a
stop remote
~
Quitting and restarting altosui makes the TeleMetrum start transmitting
(as seen on the specan) but the serial debug output and UI don't show
any activity. I also can't connect to the TeleMetrum using Configure
Altimeter anymore. Debug output when starting altosui and switching to
Monitor Idle:
m 0
c s
f
v
Config version: 1.24
Frequency: 434550
Callsign: "K5RLW"
Radio enable: 1
Radio cal: 5696589
Telemetry rate: 0
Syntax error
manufacturer altusmetrum.org
product TeleDongle-v3.0
serial-number 5177
program-space 28672
software-version 1.9.5
set_radio_frequency 434.550 (freq true) (set true) 5696589
c F 434550
start remote 434.550
set_radio_frequency 434.550 (freq true) (set true) 5696589
c F 434550
c T 0
c c K5RLW
p
E 0
m 0
c s
f
v
This problem didn't occur when I had the TeleMetrum USB cable connected,
only when running on battery. I power cycled the TeleMetrum and the
beeps reported 4.0V. Idle telemetry also started working correctly
after the power cycle. Do you think RF from the other transmitter being
coupled into the battery leads could be the issue?
One observation - it appears that when in Idle mode, the TeleMetrum only
transmits packets when altosui is up in running in Idle mode, at least
what the specan shows. Is that expected behavior - a query/response
arrangement?
If you recall our conversation about the ADXL375 permanently failing
when near a 1W 900 MHz transmitter, I'm seeing some interesting data in
the serial debug output from altosui. The self test values being
reported every second or so seem to indicate the accelerometer readings
are in range. However, when connecting to the TeleMetrum over the
serial console, it reports 4086 and 4129 for the Accel cal +1g and -1g
points respectively at bootup. Maybe the self-calibration feature of
the accelerometer is what got damaged being near the other transmitter?
I commented out the accelerometer in my firmware as we discussed to make
it a baro-only device so I don't keep blowing out accelerometers and
having to send boards back.
I have one other question for you about the recovery outputs. I'm using
an external optoisolator based circuit to bridge the TeleMetrum output
channels with my other custom flight computer. So the load is just a
820 ohm resistor and the LED from a VO14642AT optoisolator instead of an
igniter. The TeleMetrum reports 3 dits when on the pad so it thinks the
outputs are good. Also, manually testing the outputs with the UI
properly actuates my external circuit. However, the UI indicates red
for the igniter status (the voltage is 3.1V). Will the firmware still
fire the outputs in this condition during flight?
Thanks,
-Bob
On 9/25/20 12:08 AM, Bdale Garbee wrote:
Yes, that's so still how it's done, but note that TeleDongle doesn't
store the cal in flash, it gets embedded in the binary. So once you
have a working cal value, re-flash the firmware providing the correct
cal value to complete the process.
Bdale
On September 24, 2020 8:40:17 PM MDT, Robert Watzlavick
<[email protected]> wrote:
Bdale,
My frequency counter only goes up to 100 MHz but I have a 3 GHz spectrum
analyzer and a 10 MHz GPSDO reference. Assuming I can get the RBW low
enough, do you think that would be sufficient?
I found this post in the archives:
https://lists.gag.com/pipermail/altusmetrum/2018-August/001364.html
I was able to get into the board with a terminal so assuming these
instructions are still valid, I can try that.
-Bob
On 9/24/20 12:54 PM, Bdale Garbee wrote:
Robert Watzlavick <[email protected]> writes:
Can you provide the radio calibration value for TeleDongle
S/N 5177?
Unfortunately, the cal value for 5177 seems to have been lost
in a hard drive failure here. If you have access to a
frequency counter, I can talk you through re-determining the
value. If not, I'll be happy to issue you an RMA and re-cal
the unit for you at no charge.
Keith - I'm very certain the TeleMetrum is not still
beeping when the problem occurs now that I think about
it. A power cycle fixes it. Are there any timeouts that
make it shut down after a while on the ground?
No, a board in either idle or pad mode will continue operating
until the battery is discharged. Bdale
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
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