Monday, March 14, 2022

More pagers

Just received my lot of 9 Motorola Advisor Gold pagers, which were sold as untested. Of them, one doesn't power up, one has a faulty backlight button, and one has a faulty LCD which still works, but displays random lines across the screen. While I don't have much use for these specific pagers, I wanted some that I could use for testing, practice changing crystals in, etc, and this lot of 9 was cheaper than most individual pagers, so I won't feel bad if I kill any of them ;) And these ones all have their capcodes on the label, so I was able to send a quick test to one, and it works! :)

Saturday, March 12, 2022

Hack the Planet!

As mentioned ealier, Hackers is one of my favorite movies. Inspired by the folks at Hackers Curator, I decided to build my own replica prop. But I plan to go one step further, and make mine at least somewhat functional. So, I've obtained a supposedly functional Motorola Advisor, plus a Motorola Bravo Encore to match Kate Libby's, plus several Motorola Advisor Golds for testing, since they were really cheap for a lot of 9. But before any of that came in (so far, the Advisor came in), I worked out how I was going to make it functional. Here is my plan:
  • Test all the pagers and figure out their capcodes.
  • Forward my Google Voice SMS to Gmail
  • Create a filter in Gmail to label SMS messages (I recommend SMS, which is in my .fetchmailrc below)
  • Allow imap in Gmail
  • Use fetchmail and a custom script to download/convert the SMS "folder" to a Raspberry Pi.
  • Use instructions here to transmit those messages to my pager, at least within range of my Pi.
So far, I've received the Motorola Advisor and made sure it powers on and holds time. I do not know the capcode, so I am working out how to find it. I have ideas, though ;) I've also configured fetchmail on my Raspberry Pi and written a custom script which leaves just the From and text of the SMS in a file on the Pi. Here's my fetchmail config.

protocol IMAP
user "" with password "" mda "/home/pi/"
folder 'SMS'
fetchlimit 1
FilenameUniqueId=$(date +"%Y%m%d_%H%M%S_%N")
echo "" > $TmpFile
while read x
#echo $x
echo $x >> $TmpFile
while read line; do
if [[ $line =~ From ]] ; then echo $line > $OutputFile; fi
done < $TmpFile
sed '1,//d;/To respond to this text message, reply to this email or visit Google Voice./,$d' $TmpFile >> $OutputFile
rm $TmpFile
Once I have the capcode of the pager, I will add code to */home/pi/* from the link above to actually transmit the text of that file to my pager. **UPDATE:** I wrote a quick script to go through all possible 7-digit capcodes:
for i in {0..99}
for num in {0..99999}
# printf -v cap "%02d%05dn" $i $num
# echo $cap
printf -v cmd 'echo -e "%02d%05d:CAPCODE %02d%05d" | sudo rpitx/pocsag -f "929037500" -b 3' $i $num $i $num
bash -c "$cmd"
sleep 30s
My pager frequency is labelled as 929.0375 Mhz, 929037500 above represents. That script sends "CAPCODE nnnnnnn" to every possible capcode on that frequency, sleeping 30 seconds between each. I do this for two reasons. First, so that when the last pager I have receives its capcode, I can break out of the script. Second, to keep it from completely spamming the frequency. I don't plan on running this without a bandpass filter and the output power is pretty low, but even so, I'd rather be a good neighbor and not interfere with anyone else. Considering the Pi outputs almost-square waves, the harmonics can be pretty nasty. Even though they're low power, a highly-tuned antenna could pick up a harmonic and piss someone off. Best to do what I can to mitigate that, and to stay within FCC part 15 rules. And the reason for the nested for loop... From 0 to seven 9's is just too much for bash on the Pi to handle via a single loop. Splitting it into two nested loops makes it begin execution much more quickly. I got tired of waiting when it was a single loop, and even only doing is to size 9's caused a significant delay on execution.

Wednesday, March 2, 2022

Russian warship, go fuck yourself!

The exchange between Ukrainian defenders on Snake Island and Russian invaders has been on my mind a lot. I won't link the clip here, since it's easily found, but how powerful is it to hear a soldier ask, presumably a superior, "Should I tell them to go fuck themself?" followed by, louder, with more authority, and directly addressing the aggressors, "Russian warship, go fuck yourself." This is quite possibly the most powerful thing I will hear in my entire life.