GoKawiilOpen-source RotaryCell kit turns vintage rotary phones into LTE devices via ESP32-S3
A hobbyist project called RotaryCell adds internal electronics to an unmodified rotary telephone, letting it place calls over LTE using an ESP32-S3-based LilyGO board, a battery, and the AG1171 ringer chip, while keeping the original handset, dial, and hook intact. The current release is a documented, hand-wired working prototype on firmware v0.10.4, with new integrated PCBs already ordered from JLCPCB but not yet assembled or validated.
GoKawiil's interpretation of the reporting above, not reported fact.
The project shows how modern cellular modules can be paired with decades-old analog telephone hardware without permanent modification, appealing to retro-tech tinkerers and preservationists who want vintage phones to remain functional on today's networks. Because it's shared as an open engineering archive rather than a polished kit, it also serves as a real-world case study in prototyping challenges like wiring density and component fitment inside constrained enclosures.
- RotaryCell lets a classic rotary phone work over LTE without drilling or altering original parts.
- The current build is a hand-wired prototype; custom PCBs are ordered but not yet tested.
- Full wiring diagrams and firmware (v0.10.4) are published for others to replicate the build.
LilyGO T-SIM7000G ESP32 LTE Module — This is the kind of ESP32 cellular dev board that makes projects like RotaryCell possible — an ESP32 paired with an LTE modem and SIM slot on one compact board. Drop in a SIM and a battery and you have the brains for turning a vintage Model 500 into a portable phone.
See LilyGO T-SIM7000G ESP32 LTE Module on Amazon → Affiliate link — we may earn a commission on purchases, at no extra cost to you. Product picked by AI based on this article; it is not a tested recommendation.Source: github.com, 2026-09-01
Published there as: “RotaryCell: Making an unmodified rotary phone work over LTE with an ESP32-S3”
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