The receipt printer

A Raspberry Pi, an 80mm thermal receipt printer, and a Telegram bot. New as of July 2026, in daily use since.

What is it?

  • A little always-on printer in the corner of the room. I message a Telegram bot (or hit ⌃⌥Space on the Mac) and a styled paper chit prints
  • Six typographic styles depending on the job — there’s a ‘god ticket’ style for the big stuff and a ‘ledger’ style with little trend charts for money
Photo: a chit printing

What it prints each morning

  • My calendar for the day (08:15)
  • A workout heatmap, steps, and weight trend (08:10)
  • Net worth, Mondays and Thursdays (08:25) — daily turned out to be more paper than I actually glanced at
  • The ‘ugh field’ — a list of the tasks I’ve been avoiding, merged from both the Mac and the Pi, printed where I can’t ignore it
  • While saving for a Lisbon trip it also printed the trip-pot balance every Saturday
Photo: a morning’s chits lined up

Why paper

  • A chit is the anti-notification: it doesn’t buzz, doesn’t update, and doesn’t have other tabs. It just sits there curling at me until I deal with it
  • There’s also a quiz mode (/grok) that prints questions about something I’m learning, so I can test myself on a walk and check the answer key at home

How it’s built

  • Pi 3B+ on the LAN, python-escpos, systemd timers
  • A warm HTTP daemon so prints land in about a second — a cold start cost ~5 seconds, which was somehow unbearable
  • USB-brownout retry logic, learned the hard way (cheap thermal printers brown out the bus mid-cut)
  • The Mac’s only job is rsyncing money data over each morning; everything else runs on the Pi

← the stack