DIY OLED Smart Watch

OLED DIY Smart Watch

What is better than making your own smart watch? Making one with an OLED display. This is exactly what [Jared] set out to do with his DIY OLED smart watch, which combines an impressive build with some pretty cool hardware.

When building a DIY smart watch, getting the hardware right is arguably the hardest part. After a few iterations, [Jared's] OLED smart watch is all packaged up and looks great! The firmware for his watch can communicate with the PC via USB HID (requiring no drivers), contains a “watch face” for telling time, includes an integrated calendar, and support for an accelerometer. His post also includes all of the firmware and goes into some build details. With the recent popularity of smart watches and wearable electronics, we really love seeing functional DIY versions. This is just the beginning. In the future, [Jared] plans on adding Bluetooth Low Energy (BLE), a magnetometer, a smart sleep based alarm clock, and more! So be sure to look at his two older posts and keep an eye on this project as it unfolds. It is a very promising smart watch!

With Android L including support for smart watches (in the near future), it would be amazing to see DIY watches (such as this one) modified to run the new mobile OS. How great would it be to have an open hardware platform running such a powerful (open source-ish) OS? the possibilities are endless!

The iFind Kickstarter Campaign Was Just Suspended

A little more than one month ago we featured a Kickstarter campaign that was raising quite a lot of eyebrows and over half a million dollars. This particular product was a battery-free tag meant to be attached to anything you may lose in your daily life. It was supposed to communicate with Bluetooth Low Energy (BLE) devices and have a 200ft (60m) detection range.

The main claim was that the iFind could harvest enough power from existing RF fields inside a typical home environment to operate for centuries. As Kickstarter just cancelled its funding a few minutes ago it seems that the basic maths Hackaday did a while ago were correct and that the project was in fact a scam. We’ll direct our readers to this particular comment that sums up all the elements pointing to a fraudulent campaign and show you the email that the backers received:

A review of the project uncovered evidence of one or more violations of Kickstarter’s rules, which include:

  • A related party posing as an independent, supportive party in project comments or elsewhere
  • Misrepresenting support by pledging to your own project
  • Misrepresenting or failing to disclose relevant facts about the project or its creator
  • Providing inaccurate or incomplete user information to Kickstarter or one of our partners

Putting aside this news, this campaign’s cancellation raises a bigger question: why didn’t it happen before and how could we control Kickstarter campaigns? On a side note, it’s still very interesting to notice the nearly religious fervor of the sunk cost fallacy that such campaigns create in their comments.

Thanks [Rick] for the tip!

Ask Hackaday: Can Battery-Free Bluetooth Item Locating Tags Exist?

iFind Tag

[Vishak] tipped us about the iFind Kickstarter campaign, a 1.25×1.06×0.09″ (32x27x2.4mm) tag meant to be attached to anything you may lose in your daily life. This device communicates with Bluetooth Low Energy (BLE) enabled smartphones, has a 200ft (60m) detection range and a loud alarm. What is interesting to mention is that this device doesn’t need any battery to operate as it

recycles electromagnetic energy and stores it in a unique power bank.

As you can guess, this particular claim intrigued the Hackaday team given that we never featured so small energy harvesting devices. The ‘closest’ thing that comes to our minds is the Allsee project, a simple gesture recognition device that uses existing wireless signals (TV and RFID transmissions) to extract any movement that occur in front of it. However the antenna was quite big and very little power was extracted.

A quick Google search let us know that Bluetooth Low Energy solutions usually consume an idle current of around 10uA @ ~3V. The (very) successful Sticknfind campaign which promoted the same battery-enabled product claimed a one year autonomy with a CR2016 battery and a 100ft range, leading to a ~90mAh/24/30.5/12 = 10.2uA idle current. As we’re not expert on the subject, we would like to ask our readers if they ever came across such energy harvesting performances (3V*10.2uA = 30uW) in a normal home environment. Our very bad maths indicate that if one would like to extract power from a typical Wifi router located 2 meters from you emitting 0.5Watts of power (in a perfect vacuum environment) with a 32*27mm = 864mm = 0.000864m² tag you’d only be able to get 0.5 * (0.000864/(4*pi*2*2)) = 8.6uW.

It is therefore too bad that we can’t see in the presentation video what is inside the iFind, nor more details about the patent pending technologies involved. We hope that our dear readers will enlighten us in the comments section below.

Sending data over Bluetooth Low Energy with a cheap nRF24L01+ module

nRF24L01+ modules like the one shown above are a great way to send data wirelessly between your projects. They can be found on many websites for less than $1.50

a piece and many libraries exist for them. After having thoroughly looked at the Bluetooth Low Energy (BLE) specifications, [Dimitry] managed to find a way to broadcast BLE data with an nRF24L01+.

Luckily enough, BLE and nRF24L01+ data packets have the same preambles. However, the latter can’t send more than 32bytes in a packet and can’t hop between frequencies as fast as the BLE specification wants. [Dimitry] found the solution when he discovered that he could send unsolicited advertisements on three specific channels. In the end, considering the 32 bytes the nRF24L01+ can send, you’ll need to use 3 bytes for the CRC, 2 for the packet header, 6 for the MAC address and 5 for devices attributes. This leaves us with 16 bytes of pure data or 14 bytes to split between data and name if you want your project to have one.

Fail of the Week: Smoking pulse sensor and BLE disappointment


We think [Thomas Brittain] is onto something. We often post to our personal blogs so that we have a reference to how we did something. But he also keeps a long post that documents his abandoned projects. It ends up serving as a quick start if he ever decides to pick up the torch once again. Lucky for us he’s included his failures in the write up. This Fail of the Week features the top two posts on his Incomplete Works page. The first is an attempt to make his own pulse sensor. The second is a miserable experience with a cheap Bluetooth Low Energy module.

[Read more...]

Bluetooth Low Energy weather lamp


This is a well-executed proof of concept which [Aaron Jeromin] threw together in a couple of hours. This lamp hosts a Bluetooth Low Energy weather display. The project was a way for him to get used to using the BLE module. But to make the most out of that hardware this should really be refined into an actual low energy circuit. We do think the timing is perfect to feature this project since we just looked at a BLE primer yesterday.

He’s using a BLE Mini board from RedBearLab. It uses a Texas Instruments CC2540 SoC. We’d love to see a follow-up that does away with the Arduino in lieu of code running on the TI chip. But we would have done the same thing (use the uC we were most familiar with) when testing the BLE board out for the first time. It gets weather data from an iPhone. The forecast is projected as one of three icons using an LED bulb and a stencil which is positioned by a hobby servo.

Other inanimate objects that can tell you if it’s storming include this color-coded umbrella stand.

[Read more...]

Primer on Bluetooth Low Energy


We’re sure that, like us, you’ve heard at least something about Bluetooth Low Energy (BLE). Blutooth 4.0 is another name for BLE and it’s already available in some smartphones; starting with the iPhone 4S, BlackBerry 10, and with Android support added in 4.3 — Jelly Bean. Here’s your chance to get acquainted which what the specification brings to the table. The source material (which we’ll talk about below) provides a ton of background. But if you want a succinct overview check out [Gervasi's] summary of Bluetooth Low Energy.

We won’t republish the technical details here as both articles do a great job of covering those. Here’s what you should take away from BLE: It’s meant for use with devices running off of a tiny power source. The one outlined in both articles is a coin-cell. But we prefer to think of the future that is energy harvesting. Peak current is limited to 15 mA. This does limit the throughput, but think sensors, not Bluetooth headsets. You just don’t need to push all that much data from these devices. A cleverly designed energy harvesting circuit should be able to implement BLE devices with no battery whatsoever.

We did mention a deeper exploration of the standard. The image above comes from this BLE Primer for Developers. Add it to your weekend reading.

[via Reddit]