Maypole Adapts microSD Cards to WiFi and USB

Turn any USB port into a hub for wireless collaboration.

James Lewis
3 months ago β€’ Internet of Things

UPDATE (2020-12-13): The Maypole campaign is now live. Prices run $29 (plus shipping) for a standalone Maypole or $35 (plus shipping) for a Maypole with a battery. There is also an option with an attached programmer.

The original article continues below.

Hardware developer Akshar Vastarpara is about to launch a Crowd Supply campaign for an open source product called Maypole. It's an ESP32-powered device that shares a microSD card over USB or WiFi, or both at the same time.

"Suppose, for example, you have a printer with the ability to read files from a USB flash drive," Vastarpara explains. "By plugging Maypole into that USB port, you can allow anyone on the local network to send print jobs."

Maypole's concept sounds familiar to full-sized SD cards which implement WiFi. However, those devices tend to be closed source and require an SD card slot. Maypole works with devices that support USB mass storage devices, is an open design, and includes support for Bluetooth and BLE.

Either the USB host can read/write to the files on the microSD card or a WiFi client can access the files through the ESP32. The example Vastarpara gives is for printers. We got to thinking that this device could be useful for test equipment like oscilloscopes. Most save screenshots to USB drives but do not include WiFi (or even Ethernet) support. Maypole would eliminate the need to shuttle USB sticks around the lab.

An ESP32-PICO-D4 offers connectivity like 2.4 GHz WiFi, Bluetooth 4.2, and BLE. There are two options to power Maypole β€” one is, obviously, a host USB port, while the other is a LiPo battery for stand-alone wireless operation.

Being an open project, Vastarpara plans to provide sample code and more documentation when the project launches. As of this writing, Maypole is in the pre-launch stage on Crowd Supply. Join the Maypole announcement list for updates and a notification when the campaign goes live.

James Lewis
Fan of making things that blink, fly, or beep. Oscilloscopes for R&S, host on element14 Presents,, AddOhms, and KN6FGY.
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