nexttrain

rpi box that tells me when the next metro is coming

• next_train_term.py: prototype that displays train info in the terminal
• next_train_lcd.py: raspi 16x2 character lcd version

Added to /etc/rc.local - run in the background. using python3 -u to not buffer the log file, in case there are transient errors i want to check on

disabled gui in raspi-config. should save some cpu/mem.

requirements.txt is way too much - just copied user env over to sudo env. but fine for now.

circuit notes

• PFET to turn on backlight. this maximizes the brightness when on but does mean it's active low - i.e. when program not running, backlight on.
  • default pull up maybe? added gpio=10=op,pu to /boot/config.txt. didn't seem to do anything.
• trimpot for contrast
• should move schematic/board into here eventually.
• first solder-up didn't work because i mounted the transistor, and the raspi pin headers, backwards.

todo maybe

• improved logging if errors
• press and hold for debug? inet connectivity, etc.

first case print notes

• button is tight but that's fine. Not really room to screw in the collar.
• need a bit more vertical room for the rpi. should be LOOSE to slide in.
• display
  • vertical: is 26mm, needs to be 26.5
  • horizontal: is 71mm, needs to be 71.4
• adjust USB

Wifi

After moving, needed to update the wifi! and forgot how... This did it:

Create wpa_supplicant.conf:

country=US
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network={
  ssid="WIFI NAME"
  scan_ssid=1
  psk="WIFI PASSWORD"
  key_mgmt=WPA-PSK
}

and copy to the SD card boot partition.