We mentioned in the previous update that the iPad model will be tested in the Apple’s authorized lab. The testing result came back 2 days ago as shown below with confidential info deleted: 


During an audit, this sample was found to have the following issue:

-The following error message is coming in the ATS log


Accessory did not stop drawing high power within 1 second after being notified to switch from Intermittent High Power mode to Low Power mode

MFi Spec Reference  

File:Accessory Interface Specification R14 Section: Exiting Intermittent High Power Mode


The good news is that the testing result only has one minor issue, and we just fix the bug and prepare the sample for testing again. Once Apple approves iPen 2, we will be able to begin production in few days. In the meantime, we’re also filing the FCC and CE certification for iPen 2.

The iMac model

After extensive calibration testing, we have to switch to higher resolution sensor for accuracy because the 27” iMac screen is 4 times bigger than the iPad screen. Unfortunately, there is no existing sensor available, so we have to build it from scratch. We expect the new sensor will take 45 days to complete. By upgrading to the new sensor, we want to ensure iPen has the excellent performance on iMac. Due to the increasing production cost, we also have to increase the retail price to $219, but it will not affect your original pledge. The new sensor is our last challenge for the development. We will let you know once the new sensor is complete.



We’re very close to the release date, and we’re confident you will enjoy the excellent performance of iPen 2. The iPen 2 goes to Apple for initial MFi approval next week. During this initial testing, Apple will test the iPen 2 for voltage consumption, third party app compatibility, and safety. We expect the initial app integration will be ready this week, and will send out the sample to Apple between April 8th and April 10th. After we pass the initial testing, we expect to send the retail unit to Apple for final approval between April 14th and April 25th. It should take 2 to 3 weeks to get the final approval. If all goes as planned and Apple’s approval process adheres to the time table, we should ship out the iPen 2 for retail sale by mid to late May.

In the meantime, iPen 2 has to be approved by the FCC and earn standard safety certifications. We are also working with our existing app partners (e.g. Goodnotes, ibisPaint, Noteshelf, Sketch, etc.) for further integration. Once our initial integration is complete, we will send an evaluation kit to other app developers such as Adobe, Procreate, and Sketchbook. If you would like your favorite apps to work with iPen, you can ask your app developer to access our public SDK here.

The iMac Model Progress

We have finished the revised mechanical design for the iMac model, and will start to build the engineering sample very soon. Once this sample is complete, we will issue an update. We expect to release the iMac model in this July.

As we near mass production, our confidence in our product grows. Our hard work for these past 23 months has resulted in an outstanding stylus, far superior to the competition. While a design that fit the iPad case would have been ideal, we are pleased that our revised design allows for superior performance. Due to the Chinese New Year, we will review our T0 sample (iPad model) this week, and expect to have the T1 sample ready by February 26th. The following are our main production milestones:

  • February 19th SMT/PCBA Testing (revised version) 
  • February 24th Engineering Run Assembly/Test
  • February 27th - March 13th MFi Review I
  • March 14th - March 17th Possible Revision after MFi Review I
  • March 26th Production Run Assembly/Test
  • April 1st – April 8th MFi Review II
  • April 9th – April 11th Mass Production

We are actively mitigating risks inherent to mass production. Cregle is now building several customized testing tools and software to control quality in the assembly line. We’ve learned that each receiver must be manually adjusted in the assembly line, due to the precise angle necessary for the sensors on the receiver, and we are taking steps to make mass production as smooth as possible.

The iPen 2 will release with 2 additional apps: Calibrator and Showroom. The calibrator app will allow users to calibrate the iPen 2 and configure other settings; and with Showroom, users can try iPen 2 with potential features that are available to app developers to integrate through our public SDK. The following videos are taken with our engineering sample. We will release more videos when our T1 sample is ready.

We are excited that the iPen 2 performance is far superior to that of our competitors. Its accuracy, palm rejection, and ability to write on non-touch screens validate our efforts and your support. We’re pleased to report that development for the iMac model is progressing nicely. Your patience will pay off. Thank you for continuing to give us the time to focus our attention on finishing what we started, and bringing this product to the world.

Warm Regards,


We have decided to upgrade the performance of our iMac receiver by converting it from the original wireless design into a wired version. The new wired version has far superior battery life and a much more pleasing aesthetic.

We are working on finalizing the customized cable for the iMac receiver. This special design cable will have six interior wires for power and communication between the iMac and iPen. Once we ascertain the exact dimension of this customized cable, we will finalize the iMac receiver design; a design which will not only allow for optimal performance, but will be sleek and attractive as well (as the receiver does not house a battery).

Below you’ll find the stylus stand and charger for the iMac model, which will allow for easy storing and charging of your iPen. We look forward to bringing you the next update which will include our progress and images of our newly designed receiver.

Warm Regards,



Our primary focus is, as ever, the iPen 2. While we have been beset with delays, and incurred significant additional costs - we made the decision from Day 1 that we would rather delay the release of the iPen 2 than to compromise quality. We greatly appreciate your continued patience and support.

We launched the Cregle ‘ink’ for the following reasons:

  1. To raise additional funds to support the continued development of the iPen 2
  2. To gain brand awareness among general users
  3. To take advantage of technology we had already perfected
  4. To take advantage of the market awareness for general use fine-tipped styluses following Adonit’s release of the Jot Script

This month marks the 20th month that the iPen 2 has been in development and we are now within striking distance of our goal. The iPen 2 tests head and shoulders above other styluses on the market. Other brands, like the Jot Script, have less accuracy and no pressure sensitive. We can’t wait to show you, our faithful supporters, and the market where our long journey has taken us.

An additional infusion of capital will help us run this race faster as we sprint to the finish. We are tapping every last resource to complete this project, and to complete it right. Any help you can provide in directing potential partners or investors to us on AngelList at https://angel.co/cregle would be greatly appreciated.    

“Winners get up one more time than they are knocked down.” We are rising to our feet for the final time and would be grateful for a helping hand.

Additional Receiver Holder for iPad Model

As we mentioned in Update #27, we have re-engineered our receiver to add extra support and ensure peak performance. The images below show how the receiver now comes with a transparent supporting enclosure that securely attaches to the iPad. The iPad 4 and iPad Air model will use the identical receiver with a different replaceable enclosure.

The 30-pin receiver, on the other hand, is different from the Lightning connector and requires a completely different mechanical design and tooling, which will cost an additional $50,000 to develop. The 30-pin iPad models will require a Bluetooth receiver which we will build as our business grows or with an infusion of additional capital. The overwhelming majority of those with 30-pin models have switched to the iPad 4 and iPad Air which our current designs accommodate.

Revised Stylus Design for Better Charging

During our continuous testing with the iPen 2, we found that inappropriate placement of the stylus into the charging chamber would result in an unsatisfactory charge. To ensure the proper charge of the stylus, we revised the pen cap design as shown below. This final design provides a cleaner look and will further optimize the user experience.

Stylus Charging Chamber

iMac model Development

Our development with the iPad model is mostly done, and we are now picking up our pace with regard to iMac model development. We will update you as soon as we have any news ‘fit to print’.


From all of us here at Cregle - Happy Holidays to you and to yours.


We remain committed, as ever, to delivering the best product possible to our customers and the market at large - and are sincerely disappointed that the iPen 2 is not yet ready for delivery. In balancing the priorities of full functionality of the promoted features with the timely production of the iPen 2, we made the decision that we would rather produce the 'right' product late than the 'wrong' product on time. We thank you again for your continued support which makes the ongoing re-engineering process possible.


Understandably, many customers are interested in the details surrounding the delay - so we will provide you with details throughout the remainder of this update. The nature of the delay is mechanical, and we were compelled to revise our mechanical design to ensure the iPen 2 would perform as promised. Furthermore, our efforts hinge on our ability to acquire necessary components from Apple, which have furthered the delay.


Mechanical Design


Specifically, we made changes to the receiver mechanical design. The receiver is equipped with a pair of camera sensors. The sensors can triangulate the exact distance from the invisible light emitting from the pen tip to the writing surface. In order to reduce interference from other light sources, the sensor has a viewing window set to 3 degrees. (see Fig 1) Because of its tiny sensing window, the sensor will only see the pen tip if the receiver is perfectly still - in other words, if the writing surface (iPad) is resting on something solid like a table. Because so many of us used to rest our iPads on our knees, rest them on uneven surfaces, or hold them in our hands - we needed to make a critical adjustment keeping in mind the following: 1. that the receiver must attach firmly to the writing surface (iPad/iMac), and 2. that the receiver must stay slim so it can blend into the whole aesthetic iPad/iMac body.

Fig 1


The original design of the iPad receiver was to embed the sensor, circuit board and pen slot into the iPad protective case, which is approximately 9.4" high by 7.5"wide and 0.08" thick (see Fig 2) It turns out that our selected manufacturers cannot warrant this design for mass production because of two concerns. First, the ABS injection molding will be twisted in making such a big iPad case, resulting in compromised performance. The sensor will only see the pen tip if the molding case is uniformly flat. Second, implanting the receiver chamber into the case also reduces mechanical strength. This left us with the only viable alternative - using a dongle receiver similar to that used with the iPen 1.


Fig 2


The dongle design will accommodate different models of iPad with a 30-pin or a Lightning connector. To ensure the dongle can safely secure to the iPad, and fit to the Smart Cover as we claimed - we fashioned a receiver that attaches to the iPad (Fig 3) through the Lightning connector. Adding to the delay is the fact that Apple released a new type C12 Lightning connector last month. It's likely that the C11 will get discontinued, rendering our original design obsolete. So we started to integrate this new connector into our design as soon as we received the sample. Fortunately, the C12 connector is better for production assembly and will make the receiver much smaller. In Fig 4, you can see the receiver with the C11 connector, and the other smaller receiver with C12 connector.


Fig 3


Fig 4


Our Commitment


Our commitment to you is not only to deliver the iPen 2, but to deliver the best possible iPen 2. Our production of iPen 1 reinforced our belief that while both performance and aesthetics are critical, performance is paramount.  Our new and improved design bypasses the notion of the Smart Cover support, and ads additional mechanical support from the iPad screen to prevent sensor displacement and compromised performance. See Figure 5 for an example of sensor displacement.


We also decided to use the C12 connector instead of the C11 connector. (See Fig 6) By using the C12 connector, it's easier to modify the revised mechanical design with the 30-pin connector, and allows for a smaller receiver. That said, the 30-pin model will have similar ID design to the Lightning model.


Fig 5

Fig 6


iMac Model


We will release the iMac and iPad models together. Our current focus is on the iPad model. Because there is little deviation between the two models, our mechanical engineer and electrical engineer will complete the iMac model promptly after iPad model design is complete.


Release Date


It's going to take 4-6 weeks to complete the modified receiver. The lead time for the C12 connector is 8-12 weeks based on Apple's supplying notice. This is depressing news, but the actual delivery date of the iPen 2 is going to be in the late Feb or early March of 2014, assuming we receive the C12 connectors when promised.


iPad Air & iPen 2 Bluetooth Models


The iPad Air is smaller than the previous iPad. We will make the iPad receiver compatible with iPad Air but this is not our current priority. We will also work on the Bluetooth iPad Receiver when we complete the iPad and iMac model production.


Refund Policy


We thank you again for your patience, and are confident you will be pleased with the improvements we're making to the product that have delayed its delivery. Based on our terms, we will honor your request for refund if we are unable to deliver iPen 2. Your patience and support will be rewarded many times over upon delivery of a now superior product.



Our resources are limited, but your support makes all our work possible. We wish we had enough manpower to test various designs simultaneously to meet the schedule, but we are operating on a shoe string budget. We can assure you, however, that the promoted features of the iPen 2 such as Angle Agnostic Writing, Lightweight Inking, Palm Rejection and Speedy Writing Performance are all built into the end product. The mechanical design issues were unforeseen, but we are glad we caught them in time to make the necessary product revisions. In this lengthy update, we hope our supporters can appreciate our efforts, and continue to support this project.


We share in the frustration of those eagerly awaiting the rollout of the iPen 2. We thank you for your persistent interest in our development and production schedule. If you think of any additional features that will add value to our line of writing products, we are all ears. Our goal is, as ever, to make the best iPen 2 possible, and a product you are proud to have supported and to own.


We understand everyone is anxious to receive iPen 2, and the unexpected delay is making all of us frustrated. Now we have the final design with several benefits. First, the stylus is much easier to hold with enlarged rubber strip. And we adjust the side button to half inch higher to avoid accidental click. Second, the new receiver design can fit into many of your existing iPad case. It is very likely to fit into the incoming iPad 5. The new design will also be compatible with iPad mini, but we will release a smaller receiver exclusive for iPad mini in near future. This design change is the most difficult decision we have to make, but its versatility is a cost-benefit merit to all of us. For iMac model, please expect a totally new ear-plugged design soon. We intend to have the new miniscule receiver blend perfectly into your iMac screen and other glass screens.


The tooling will take 45 days to commercialize iPen 2. With the following required tasks, we can only expect to deliver iPen 2 (both iPad & iMac models) by this November:

  • Send demo samples to app developers for evaluation and integration by September 30. Those app developers include Adobe, Art Studio, Good Notes, ibisPaint, Noteshelf, Notes Plus, Procreate and Sketchbook.
  • Submit final MFi process by October 17 for Apple approval.
  • File FCC by October 17.
  • Complete final testing by October 31.

Drawing on ibisPaint

August 11, 2013

ibisPaint   iPen 2   video  

Here is the drawing video in ibisPaint. With improved SDK, the drawing performance is much better than capacitive stylus. The black stylus you see on the video will be replaced with anodized aluminum body and customized fine pen tip. We are very sorry for the production delay, but your patience will be worth it. We will have updated release schedule coming out soon.

In previous update, we talked about the iPen 2 calibration app, calibrator, which is built based on iPen 2 SDK.  So if we want to debug iPen or test its performance, the best way is to observe its drawing behavior inside calibrator, and then deal with foreseeable problems. And once the problems are resolved inside calibrator, the SDK is fixed at the same time. It’s like both calibrator and SDK have the same engine. In the past few months, we had observed the drawing lag in calibrator, and tried to fix it with several hardware and software modifications. We’re glad we finally have the answer today.

The following videos show no lag during drawing test. You will also notice the stylus draws dots, instead of lines for demo purpose. In order to kill the lag and optimize drawing stroke, we have to increase the number of PPS (packet per second) sent from iPen receiver, and make sure iOS can catch those packets on time. Generally speaking, each packet represents one single dot. iPen 2 can generate 100 dots per second if we set PPS = 100. iPen 1 has only 30 PPS due to hardware restriction; and iPad touch event has around 60 PPS based on our calculation. This means iPen 2 has  potential to draw faster than finger touch or any capacitive stylus. However, this is a complicated subject. We will explain it later on.

Live long and prosper \\ //


iPen 2 straight line testing in calibrator dot mode - no jitter


iPen 2 angle agnostic testing in calibrator dot mode


iPen 2 pressure sensitive testing with calibrator in dot mode

Today, we would like to talk about the new iPen calibration app, calibrator. It is the standalone app for iPad, iMac and future compatible devices. And it is the only place to calibrate iPen 2. In releasing calibrator and SDK, we make the app integration so easy that app developer won’t need to deal with calibration again. In fact, we tried to integrate third party sample app with iPen 2 last week, and it only took us 10 minutes to get it done.

In the following screenshot, you can see 4 sections on the left: {Try Here}, {Calibration}, {Side Button} and {App List}.


In {Try Here}, you can test iPen 2 to see if it works. The bottom semi-circle will show you the values of coordinate (X, Y) and pressure in real time during drawing.


This is where you can calibrate iPen 2.


In {Side Button}, you can customize what side button does for you. The ON & OFF means you can either activate or disable the side button. If you activate the side button, you can customize the button to Redo, Undo, Erase and Save inside the iPen 2 supported apps… but only if developer adopts this feature.


After we release iPen 2, you can see all the supported apps in the {App List}. This section will be updated on a regular basis to exhibit all our app partners.

Have a great weekend :-)