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The SonarPen is a battery-less and pressure sensitive smart pen that turns all iPad, iPhone, Android and Windows PC into a professional creative canvas. Shipping now.
The SonarPen is a battery-less and pressure sensitive smart pen that turns all iPad, iPhone, Android and Windows PC into a professional creative canvas. Shipping now.
2,357 backers pledged HK$ 724,129 to help bring this project to life.
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SonarPen: World's most affordable Smart Pen project video thumbnail
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SonarPen: World's most affordable Smart Pen

HK$ 724,129


What is a prototype?

A prototype is a preliminary model of something. Projects that offer physical products need to show backers documentation of a working prototype. This gallery features photos, videos, and other visual documentation that will give backers a sense of what’s been accomplished so far and what’s left to do. Though the development process can vary for each project, these are the stages we typically see:

Proof of Concept

Explorations that test ideas and functionality.

Functional Prototype

Demonstrates the functionality of the final product, but looks different.

Appearance Prototype

Looks like the final product, but is not functional.

Design Prototype

Appearance and function match the final product, but is made with different manufacturing methods.

Production Prototype

Appearance, function, and manufacturing methods match the final product.

Project supporting material callout image

Prototype Gallery

These photos and videos provide a detailed look at this project’s development.

SonarPen is a battery-free smart pen that's packed with smart features. Just connect it to the 3.5mm audio port on the iPad, iPhone or Android. Your professional creative canvas is now ready for you.

All of this, at the price of 5 cups of coffee.

The pen is one of the first tools we learn to use as a child, so creating with a pen is second nature to us. Using SonarPen, we can do all these tasks easily like using a real pen:

Cause SonarPen let you control the strokes on the screen by sensing the pressure from your hand.

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Current smart pens on the market are expensive. Some only work with the latest iPad Pro models. This bothered us for a very long time, so we created a smart pen that's more financially accessible for everyone.

The SonarPen has the same features as a smart pen, including palm rejection, shortcut button and pressure sensitivity. Our innovative design lowers the amount of materials used and we're passing the cost savings to you.

SonarPen is the most affordable smart pen for virtually all iPads, iPhones and Androids.


Many smart pens are powered by a built-in battery. Within a year or two, the smart pens will stop working since the battery can no longer hold its charge. This creates more unnecessary e-waste.

Our innovative design makes the SonarPen a battery-free device so you'll never have to discard it. It will also works with all iPad models produced over since March 2011 (all except iPad 1st gen).

Just like the pen and paper belonging together, we've developed a pen holder that attaches you SonarPen to the iPad. This way, you won't have to hunt for your SonarPen in your bag.

The magnetic pen holder attached to the back of your iPad with a piece of 3M double side tape. Installation is super easy and it doesn't leave any dirt on the iPad when you remove it. 


To suit everyone's style choices, cables come in a range of colors. Choose a color that suits you!

SonarPen will be available with 6 cable colors; black, white, Red, Blue, Purple and Neon-Green. The rest of the color options will be unlocked as stretch goals are reached.

** Actual colors may vary**

We've spent over 2 years developing the technology and putting our manufacturing process in place.

When you back this project, your contributions will go to the initial production costs. We're very excited to mass produce the SonarPen.

We developed over 24 prototypes for the SonarPen. We finally settled on the best design that we think you deserve for your smart pen. 

Photo of some of the SonarPen prototypes that we built, grandpa SonarPen is on the right.

We are working with many developers to add support of SonarPen and allow users to take advantage of all the SonarPen's smart features.

Zen Brush 2, the popular water color painting app, is the first official app that supports the SonarPen. Other apps will be supported soon. If your favorite app is not listed, feel free to let us know.

Check out the SonarPen at the makers' event and see for yourself how easy it was to use.

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 More goodies will be unlocked when the stretch goals are reached. 

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 Here is our master plan, we follow it tightly to avoid delay.

Q1. Does the SonarPen work with iPhone?  

A1. Yes, SonarPen works with iPhone 4S and newer.   

Q2. What happen if Apple removes the 3.5mm audio port in the future? 

A2. We aware of the chance that Apple may remove 3.5mm audio port from all its future products. But We are happy to tell you that SonarPen works with iPhone that only has a lightning port (iPhone 7, 7+, 8, 8+, X), just connect the two with the conversion dongle that comes with the phone. 

Q3. Any plan for SonarPen to support Android and Windows devices? 

A3. SonarPen is designed to work with Android and Windows. However, we have no resource($$) to start the driver development for these platform, that’s why we are here to crowdfund. Your support will definitely speed up the development process for these two platforms.

Q4. Is there a figure for the number of pressure levels supported by the SonarPen?  

A4. SonarPen is the first analog smart pen for the iPad. Its supported pressure level is not predefined by us the designer, because it doesn’t contain an analog-to-digital converter that governs the number of pressure levels. SonarPen uses the iPad's built-in ADC it connected to do the conversion. Generally speaking, ADC in the iPad has higher resolution than the ones found in all smart pens, which means SonarPen detects more pressure levels. Although SonarPen beats the others in pressure levels, but we are not trying to play up the number game, so you don’t see us brag about it.

Q5. Can you post close up video of how the pen draw?

A5. Here is a speed drawing video of a crowded subway cabin in Hong Kong. (by @fatlundraw with SonarPen and iPad 2017 on Zen Brush 2)

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Q6. Will the SonarPen work in XXXX app?  

A6. SonarPen works as a smart pen when the apps that officially support it (like Zen Brush 2, ZoomNotes). For all other apps (like Safari, the default email app), SonarPen will still works as a regular (dumb) stylus. Here is a video:

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 Q7. I am a professional artist, I like to know does SonarPen has parallax effect like those really cheap 1.9mm narrow active stylus from China?

The disc nib on SonarPen gives you on the spot writing/drawing experience. The ink always appear at the center of the disc. See it for yourself. NO PARALLAX.


 The SonarPen team is small but we are very good at what we do.

From the team: Thank you so much for checking us out. Drop us a message if you have any questions and we hope to have you on board soon. :)


Big thanks to Wayne, for his help on produce the wonderful video. I recommend him to anyone.

Last but not least, music used in the video is: 
Drops of H2O ( The Filtered Water Treatment ) by J.Lang

This campaign is promoted by Backercamp. Since 2012, Backercamp has helped over 5,000 creators make their projects a reality.

This project is promoted by Green Inbox
This project is promoted by Green Inbox

This project is promoted by Green Inbox Partner Program which includes risk free Facebook ads and press coverage.

Risks and challenges

As this is our 3rd crowdfunding project working with stylus products, we've minimized the project risks when compared to other new smart stylus projects.

During the development phase, we've asked creatives to test the SonarPen. By listening to their feedback, we're highly confident that the SonarPen is the smart pen that people want.

We believe in making reputable products that last. Equally, it's a way to continue building a sustainable long term business. To keep things transparent with our backers, there are some project risks that you should be aware of.

1) Procurement risk: to minimize delays with our suppliers, we've sourced parts form several suppliers. The quality from each supplier is consistently high.

2) Shipping risk: There may be a delay depending on the customs requirements for each country. This is unlikely to happen as the SonarPen does not contain any parts that needs any specific certifications.

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Funding period

- (45 days)

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