[amsat-bb] Re: APRS & Twitter

PA3GUO pa3guo at upcmail.nl
Tue Jul 9 23:52:16 PDT 2013

Hi Rizwan,

First of all: we are all very interested in your CAPE-2 project. 
Would you be able to share some more information on CAPE-2 ?

In case you involve radio-amateurs in capturing telemetry/data from your satellite you will have an huge increase in coverage, as we are spread across the entire globe. We do have the APRS system up-and-running, and NO-44 (PCSAT-1) and ISS-APRS data packets for example are monitored and automatically forwarded to the internet already.

On messaging to twitter email:
In case of a malfunction or wrong software setting the satellite may not be able to change its transmission pattern, when it is in space and cannot be reached anymore (e.g. up-link broken). Alternative would be to break it up in two steps:

Step 1
Transmit a status in APRS format, and have that captured/received as regular packets. Here is for example how all the ISS data (real-time) looks like: http://www.ariss.net, and here is how NO-44 looks like: http://www.findu.com/cgi-bin/pcsat.cgi

Step 2
Have a software program running that looks at the the received APRS telemetry, and derive from that a Twitter tweet (every hour, every day, ...). For example if the telemetry says: "CAPE 012000105" this could mean I am alive and battery voltage is 10.5 volt and temperature is 12 degrees Celsius. The tweet could be: "Hi this is CAPE-2 in space, I feel cold (12C) and my battery is good (10.5V)".

Just a thought.

Regarding APRS email: http://www.aprs.org/aprs-messaging.html explains how to do this.

Here is an example on how this worked on ANDE-1:
ANDE-1 digipeat:
!T 12:26:38 PA3GUO-8>APRS,ANDE-1*,qAO,PE1ITR::email     :pe1itr at spamsat.org  Hi ROb
!S 12:26:36 :email     :pe1itr at spamsat.org  Hi ROb

Here an example on how this worked on ISS:
TNC settings an email to PE1ABC (pe1abc at spamsat.org) via ISS (RS0ISS-3):
BTEXT  :EMAIL     :pe1abc at spamsat.org Hi there!

The result (the email received by pe1abc):
From: ksproul at rci.rutgers.edu
Date: 25-02-2004 08:00

To: pe1abc at spamsat.org
Subject: APRS Message from PA3GUO-5
Hi there!

Please let us know if this helped & success with CAPE-2!

Henk, PA3GUO

>Greetings AMSAT!
> I am one of the software engineers on the CAPE-2 Cubesat project at
the University of Louisiana at Lafayette. I am interested in
information on how to set up our satellite to tweet over APRS to a
specific twitter account.

For example:
If i want our satellite to tweet once a day what our satellite's
status is, and have it be posted to a CAPE-2 twitter account, how can
i make this happen? We've seen other groups do it, and we are
wondering how to replicate this.

Thanks for your help!

Rizwan Merchant
Call Sign: KF5BNL

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