https://github.com/werediver/pico-badge-rs

A quick weekend project of a simple electronic badge
https://github.com/werediver/pico-badge-rs

hardware

Last synced: about 1 year ago
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A quick weekend project of a simple electronic badge

• Host: GitHub
• URL: https://github.com/werediver/pico-badge-rs
• Owner: werediver
• License: mit
• Created: 2022-11-07T12:25:46.000Z (over 3 years ago)
• Default Branch: main
• Last Pushed: 2022-11-07T19:55:34.000Z (over 3 years ago)
• Last Synced: 2024-10-19T07:53:18.417Z (over 1 year ago)
• Topics: hardware
• Language: Rust
• Homepage:
• Size: 12.7 KB
• Stars: 1
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

          
# Pico badge, made with 🦀 Rust

A quick weekend project made for a Rust event. Here is a little [video demo](https://odysee.com/@werediver:d/Pico-badge-demo:8).

## Power source

The badge is designed (mechanically, mostly) to be powered off a CR2032 battery. This is a poor choice, because CR2032 capacity heavily regrades under heavier loads (heavier than a fraction of a milliampere, see [High pulse drain impact on CR2032 coin cell battery capacity](https://www.dmcinfo.com/Portals/0/Blog%20Files/High%20pulse%20drain%20impact%20on%20CR2032%20coin%20cell%20battery%20capacity.pdf), Figure 3: CR2032 coin cell continuous discharge patterns).

A better—yet still very limiting—choice would be the bigger CR2450.

After all the optimizations, the badge draws around 13 mA from a 3.3 V source, which is way too stressful for these batteries. The badge operates for around 35 minutes on a single battery, than the MCU (RP2040) ceases it's activity, but the OLED continues to display tha last frame for at least another half an hour.