# Note-emu - a drop-in virtual notecard library for note-c and note-cpp \[community project\] **URL:** \ **Category:** Firmware\ **Created:** [July 24, 2026, 5:49pm UTC](https://discuss.blues.com/t/note-emu-a-drop-in-virtual-notecard-library-for-note-c-and-note-cpp-community-project/3605 "2026-07-24T17:49:38Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![mdma](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/mdma/32/1836_2.png) [@mdma](https://discuss.blues.com/u/mdma)\ **Post date:** [July 24, 2026, 5:49pm UTC](https://discuss.blues.com/t/note-emu-a-drop-in-virtual-notecard-library-for-note-c-and-note-cpp-community-project/3605/1 "2026-07-24T17:49:39Z")
Hi all 👋 Following on from [note-cpp](https://discuss.blues.com/t/note-cpp-a-type-safe-c-library-for-the-notecard-community-project/3579), I’d like to share **note-emu** — a virtual Notecard you can use before your hardware arrives, or as part of your integration tests once it does. It’s a drop-in transport for [note-c/note-arduino](https://github.com/blues/note-arduino) and [note-cpp](https://github.com/m-mcgowan/note-cpp) that speaks to Blues’ cloud-hosted Notecard simulator (“softcard”) over HTTP. Your firmware calls the real Notecard API from day one; only the transport underneath is virtual. The [readme](https://github.com/m-mcgowan/note-emu) includes links to online Wokwi projects for `note-c` and `note-cpp`. Both Wokwi projects are ready to run once you add a Notehub personal access token - see `secrets.h` in each project. **What a run looks like** — same request/response pattern you’d see on real hardware, only the bytes go to `softcard.blues.com`: ```auto note-emu: resolved account UID: 00000000-0000-0000-0000-000000000000 === iteration 1/5 === note-emu: POST /v1/write (46 bytes) -> rc=0 http=200 [685 ms] note-emu: POST /v1/read -> rc=0 http=200 bytes=384 [132 ms] version = notecard-11.1.1.1301 ``` That `notecard-11.1.1.1301` is a real Notecard firmware version. If your `hub.set` supplies a `product`, events reach your Notehub project through the same schema, routes, and event stream you would use with a physical Notecard. The only difference is that they are attributed to a softcard virtual device. **The whole idea is that switching to hardware is a transport swap without having to rewrite your notecard calls.** Transport setup with note-emu: ```auto // Virtual: WiFi → softcard note::emu::Arduino softcard(NOTEHUB_PAT); softcard.begin(wifiClient); note::emu::SerialHal hal(*softcard.instance(), millis, delay); note::link::SerialFramer<> framer(hal); note::Protocol transport(framer); note::Notecard nc(transport); ``` Against a real Notecard, the application is unchanged, just rewire the transport: ```auto // Physical: I²C to Notecard Notecard nc; nc.begin(Wire); ``` Everything after `nc` — `nc.hub.set()...`, `nc.card.version()`, `nc.note.add()` — is unchanged. **A few things I think make it nice:** - 🌐 **Zero-install prototyping** — Wokwi browser sim + PAT → your first `note.add` in ~2 minutes - 🧩 **Works with both note-c and note-cpp** — pick your API. Umbrella headers make integration one line - 🖥 **Native builds too** — a libcurl backend for desktop tests and CI; great for regression tests that hit softcard without any hardware in the loop - 🔌 **Transport-level swap** — plugs in at the serial-hook interface (`NoteSetFnSerial` for note-c, `note::link::SerialHal` for note-cpp). Same application code all the way to production - 📦 **Standalone** — no external deps beyond your chosen HTTP backend - 🧪 **Examples for everything** — Arduino sketches (note-c and note-cpp), PlatformIO projects, Wokwi projects, a native/libcurl demo **A note on scope:** This is an independent community project — not affiliated with or supported by Blues, and “Notecard” is their trademark. It’s aimed at prototyping, testing, and integration. The README has a “Should I use this in Production?” section on why the physical Notecard beats software (cellular, power budget, security, edge reliability); but for the “waiting for hardware” and “keep our CI honest” cases, it’s a solid tool. Repo, docs, and examples: [GitHub - m-mcgowan/note-emu](https://github.com/m-mcgowan/note-emu) Feedback, bug reports, and “I tried it on X” reports are all welcome. 🙏 ---
**Author:** ![mdma](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/mdma/32/1836_2.png) [@mdma](https://discuss.blues.com/u/mdma)\ **Post date:** [July 29, 2026, 7:22am UTC](https://discuss.blues.com/t/note-emu-a-drop-in-virtual-notecard-library-for-note-c-and-note-cpp-community-project/3605/2 "2026-07-29T07:22:54Z")
Small update since posting — the transport setup and integration surface both got simpler in note-emu 0.3.3, so the code in the OP no longer matches what the linked Wokwi projects are running. Two things changed: 1. **Transport is a one-liner now.** `installNoteCpp()` (or `installNoteCppBridge()` when using note-c and note-cpp together) builds the whole streaming chain internally, so the explicit `SerialHal` / `SerialFramer<>` / `Protocol` / `Notecard` wiring in the OP isn’t needed anymore. 2. **The library also supports note-c directly, and both APIs side-by-side.** The OP only showed the note-cpp path. There are three ways to wire it now, depending on which API you’re using: **Using note-c** ```cpp note::emu::Arduino softcard(NOTEHUB_PAT); softcard.begin(wifiClient); softcard.installNoteC(); J *rsp = NoteRequestResponse(NoteNewRequest("card.version")); ``` Wokwi: [wokwi.com/projects/465203727626487809](https://wokwi.com/projects/465203727626487809) **Using note-cpp** ```cpp note::emu::Arduino softcard(NOTEHUB_PAT); softcard.begin(wifiClient); auto &nc = note::emu::installNoteCpp(softcard); auto rsp = nc.card.version().execute(); ``` Wokwi: [wokwi.com/projects/469739119860047873](https://wokwi.com/projects/469739119860047873) **Both together** (for incremental adoption of note-cpp in an existing note-c sketch) ```cpp note::emu::Arduino softcard(NOTEHUB_PAT); softcard.begin(wifiClient); softcard.installNoteC(); auto &nc = note::emu::installNoteCppBridge(softcard); NoteRequestResponse(NoteNewRequest("hub.set")); // note-c nc.card.version().execute(); // note-cpp ``` Wokwi: [wokwi.com/projects/470467610960276481](https://wokwi.com/projects/470467610960276481) The physical-Notecard side is the same swap the OP shows, just with the modern note-cpp type name: ```cpp note::arduino::Notecard nc; nc.begin(Wire); ``` Everything after `nc.begin()` — `nc.hub.set()...`, `nc.card.version()`, `nc.note.add()` — is unchanged from the virtual `installNoteCpp` / `installNoteCppBridge` versions above.