PressurePen: An open source, pressure-sensitive stylus |

PressurePen: An open source, pressure-sensitive stylus

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Charles Mangin, a web developer and consultant based in Raleigh, NC, hoped to recreate the drawing-tablet experience (such as that with a Wacom device) on what we today think of as tablets (like iPads and Android tablets)--and to do it as open hardware. The result is now on Kickstarter: the PressurePen.

Tablets are the perfect form-factor for on-the-go digital art. But very, very few of them come with a stylus, and the earliest third-party styluses made for them couldn't adjust performance to pressure.

PressurePen uses a tablet's microphone port for input to maximize its compatibility and reusability across devices. It adjusts its signal to the tablet based on how hard you press, which could apply to drawing apps in the same way that adjusting your pressure on a pencil would, or to a gaming app by changing speed or intensitiy of an interaction.

It's not the first such product to hit Kickstarter--a similar device called JaJa raised more than $65,000 on the site in February. And another called Jot Touch is expected to be available soon as well, although date and price are unavailable.

Why PressurePen then? In the case of JaJa, there's not yet a working model, although production is scheduled for this month, and their site says they'll be shipping in 12 weeks. Mangin adds, "Their ultrasonic technology is a real innovation, and thus protected by patents. The complexity of their initial offering means it's hard to know if there will end up being interference problems with ambient noise or other real-world issues, though I'm excited to see it working."

PressurePen JaJa Jot
Levels of pressure est. 1,000 1,024 200
Connection Wired to audio port Patented high-frequency sound technology Bluetooth
Shipping date Unknown; working prototype ready for production est. late June-early July possibly available later this month
Price $50 on Kickstarter, ultimate retail price unknown $89.99 around $100

Of course, the big up side to the PressurePen for open source enthusiasts is that both the hardware and its software will be open. Magin writes on Kickstarter:

The pressure sensing code will be released under an open license, and the schematics, circuit diagrams and 3D parts files will be available to anyone who wants to make or modify their own. My hope is that this will encourage more creative applications, improvements and compatible add-ons to future versions of the PressurePen.

That said, Mangin does note that he has begun the process to patent the device in order to "keep his options open"--essentially ransoming the PressurePen in the same way that some writers have done with their work on Kickstarter before releasing it Creative Commons.

Those who pledge $50 or more on Kickstarter can choose to receive the retail version of PressurePen before it's publicly available or the "maker version," which includes the prototype kit, unassembled.


About the author

Ruth Suehle - Ruth Suehle is the community leadership manager for Red Hat's Open Source and Standards team. She's co-author of Raspberry Pi Hacks (O'Reilly, December 2013) and a senior editor at GeekMom, a site for those who find their joy in both geekery and