Boogie Board Sync review

I was looking for a tool to replace all the paper clutter on my desk.

I’ve been looking high and low, and as of December 2018, to my knowledge these are the options if you want to hand-write your notes to an electronic device:

  • a iPad Pro or a Surface tablet, with an Apple Pen or the Surface Pen. They are Not Cheap (around ~1000€). I’ve only tried the Surface, and the input lag is noticeable.
  • a Samsung Android tablet with the S Pen, which, again, is Not Cheap (~700€).
  • another cheaper Android tablet with a regular capacitive pen, but the input lag is huge, and precision is poor.
  • a eInk-based tablet such as the Remarkable, which is Not Cheap (~500-600€) but seems to have very low lag (at least in the ads) and also doubles as an eReader and is capable of partial erasing; it is a very interesting concept, but the price tag led me to search more.
  • a Moleskine Smart Writing System, which uses actual pen and paper, except the paper is proprietary and while Somewhat Cheap (about 1€ for an A4) it is the only system that’ll require money for each page you use (wisely or less wisely).
  • tons of app&camera -based systems, some of which include microwave-erasable notebooks, such as the Rocket Book. These are cheaper (20-50€) but I didn’t like the idea of having to take a picture of the notebook, feeling in the end I’d just use it as, you know, a regular notebook.
  • tons of eWriter systems, which are Very Cheap (as low as 5€), with imperceptible input lag, but no “smart” features that allow exporting your sketches.

That’s where the Boogie Board Sync stood up. It is the only eWriter system with bluetooth capability and also has an affordable price tag (~60€). Due to the lack of reviews on the web, I’m writing my own.

The selling feature for me was the integration with Evernote. You can actually sketch something on the board, hit the save button, fire up the app on your mobile phone, let it sync, and have your sketch in Evernote moments after. They’ll all collect in a Evernote notebook of your choice for later reference. Unfortunately, Evernote is not able to recognize the hand-written text inside the sketches, but you can write some keywords (such as a timestamp and title) to make it easier to find it later.

The Boogie Board Sync app could definitely use some improvements. At first I tried to set it up on Windows to have it permanently available, but for some reason I couldn’t get the Evernote syncing to work on my laptop (tested on two Windows10 laptops). I tried to contact Boogie Board support but they never replied (boo!). This is really unprofessional on their part and brought me to the brink of returning the product, but in the end I figured out I could just install the app on my phone instead, which apparently works better. Also, I once had a problem where the app crashed, and upon restarting, it imported again every single sketch from the board, which had to be cleaned out manually; so even the app is not perfect.

The build quality for now seems ok. The board surface might look scratched from time to time, but it looks to be caused by the pen leaving some kind of small trail; if you clean up the screen with a cloth or a finger, you’ll have a perfectly smooth surface again.

The screen is still perfectly smooth after months of use.

On the other hand, it has shown to be vulnerable to hits. I’ve hit the screen probably by dropping my keychain on it, and now I have a couple of spots on the screen where it is much more sensible (for example, they light up if I softly push there with my finger).

A few hits to the screen led to some sensitive points. 

The pen stroke is somewhat thicker similar to the one of a soft felt tip pen, so you’ll have to adapt to writing with larger letters. Also, the screen sensitivity seems to depend on the heat (such as heat from sunlight) and it will grow bigger if the device gets hotter. Overall the vector version of your sketches is good enough to read later, but it is also not failure-proof, as some strokes (sometimes whole letters) will be missing from the end result. If your work involves symbols and numbers rather than words (such as, maths) I guess this could be a bigger issue.

How a note looks on the screen (left), and exported as PDF (right). You can notice some letters are completely missing.

A note on the software: when you delete a sketch, it is actually still accessible by using a USB cable and mounting the board as a USB thumb drive. The sketches are actually stored as vector PDFs on the board. The internal memory is probably enough for ~40k sketches.

The board can also be used as a digital drawing pad, it can left-click the screen by tapping the pen on the board, and right-click by using the button on the pen. It does not have pressure-sensitivity. This was not a relevant use case to me, but it still could be useful to someone.

Overall I’m rather happy with my Boogie Board Sync. I’ve averaged one note per day since when I had it 3 months ago and now I couldn’t go back. It definitely could use some improvements, but the concept is very interesting and as such I hope some competitors make their move with some new models.

2€ charger for any kind of lithium-ion battery

Lithium-ion batteries are everywhere and they are awesome also for hobbyist projects. I’ve been tempted more than once to use old smartphone batteries in my projects, but recharging them might be a problem.

Well, this time I tried my hand at recharging small coin-cells like the LiR2032. I’ve been looking around for commercial chargers, but they seem to be kind of unpopular. Turns out you can do one yourself with less than 2€.wpid-wp-1448223544369.jpeg

The TP4056 (datasheet here) is a little IC which serves the purpose perfectly and currently it can be found on dx.com along with an additional protection circuit for 1.57€. However, this version comes pre-packaged to work with bigger batteries (>1000 mAh) and shouldn’t be used with coin-cells. Lets see why.

The difference lies basically in the charger’s maximum charging current. The previously linked TP4056 uses 1A maximum current, but LiR2032 datasheet recommends a maximum of 35mA. This current is regulated by a resistor placed between pin2 and ground on the charger (which on this board is called R1 and has a value of 1.2kohms). So, looking at the datasheet and doing the maths it turns out a resistance of about 35kohm is needed.

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Okay. let’s go. I used

  • the TP4056 board,
  • a coin cell battery holder,
  • a 47Kohm resistor
  • a 10cm ribbon
  • some pin headers, wire, PCB and soldering

The assembling is quite straightforward, I just cut the PCB to size, mounted the TP4056 board on male pin headers, and mounted the coin cell holder over the ribbon, which I added for easier removal of the battery.

I didn’t have a 35Kohm SMD resistor available, so I replaced the old one with a “regular” 47Kohm resistor. Charging will be slower, but basically the slower the better. Soldering was doable although not trivial, a good set of pliers and tweezers definitely did help.

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I soldered the wiring on the back… double check for correct polarity.

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And voila. Charging an almost completely drained out battery took about 3 hours, during which all the assembly stayed at room temperature (based on a very accurate measurement with my fingers). Green light means charging done.

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I still have to figure out exactly how to use this thing with bigger batteries, the main issue being find a way to keep the battery still. This is probably not going to be trivial since Li-ion batteries tend to come in every shape and size. Maybe I could use cable ties or rubber bands… I’m taking suggestions!

Bluetooth low-energy temperature beacon using the nRF24L01: cheap and compatible with existing smartphone apps!

The reason I did this project is because I have a slight overheating issue in a server room; I was wondering if there would be some way to check another room’s temperature from my desk. That’s how I came up with a “wireless thermometer” that can send readings to my Android phone, and my colleagues can use it too!

You might have heard about the nRF24L01: it is a cheap (0.80€) radio frequency module that, back in 2013, Dmitry Grinberg was able to use to “fake” a BTLE beacon. Real Bluetooth 4.0 modules are, nowadays, about 5€ each.

I wondered if I could use it to make a BTLE compatible temperature beacon. Turns out there are 3 major BTLE beacon protocols: iBeacon (by Apple), Eddystone (by Google), and AltBeacon (by Radius Networks). And well, none of them can be emulated with the nRF24L01, since it is only able to send a 16-byte payload (among other limitations), and all three of those protocols require bigger PDUs.

BUT!!! Although I didn’t find a name for it, Nordic Semiconductors Bluetooth ICs (namely the nRF8001 and nRF51822) have their own protocol they use to send telemetry data (which means: temperature, battery level and device ID); turns out this protocol is simple enough to be emulated by the nRF24L01 as well, although with some limitations. They also are so nice to distribute a suite of Android and iOS apps to work with them; the most relevant apps are nRF Master Control Panel (useful for debugging BTLE devices) and nRF Temp 2.0 (a temperature logger; I think it was meant to track device overheating, but hey). You can also download the source code from the app page!

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However, the temperature in my room is quite boring, as shown from those screenshots of Nordic Semiconductors apps. (nRF Master Control Panel on the left, nRF Temp 2.0 on the right).

The temperature beacon hardware is very simple. Just wire up your microcontroller to a nRF24L01 and a temperature sensor of your choice (I used a DHT11 I had lying around).

wpid-wp-1444076633700.jpegIt’s more about how you wire them up, I guess.

 rf24-pin
(fabacademy.org)

  1.  GND -> GND on the Arduino
  2. VCC -> 3.3v on the Arduino
  3. CE -> PIN 9 (see below)
  4. CSN -> PIN 10 (see below)
  5. SCK -> PIN 13 on the Arduino Uno
  6. MOSI -> PIN 11 on the Arduino Uno
  7. MISO -> PIN 12 on the Arduino Uno
  8. IRQ -> not used

Be especially careful about the power pin: altough the nRF24L01 can work with your 5v Arduino, you must power it at 3.3v!

While SCK/MOSI/MISO are pretty much wired to 13-11-12 pins in order to use SPI, CE and CSN can be moved to a pin of your choice.

About the DHT11, just wire its output pin to A0, and the other two to ground/+5v.

On the software side, I did a couple modifications on floe’s BTLE library to allow mimicking of the nRF8001 and nRF51822; you can find the BTLE library here. With this library, you can now create your temperature beacon. (Notice I used pins 9 and 10 as CE and CSN, as mentioned previously).

Did you know? Most Arduinos have an onboard temperature sensor! The reasoning behind this probably is that a device malfunction would overheat it. Unfortunately this can’t be easily used as an ambient temperature sensor, because the chip temperature is widely influenced by its heat dissipation. That’s why I used a DHT11. (You can read more about this on Arduino Playground here).

Among other limitations, this setup is not able to use more than 3 of the 40 BT 4.0 channels, and broadcast a name longer than 8 characters (remember that 16 byte limit?). I’m pretty sure it could be used to broadcast the battery level as well.

Sadly, it does not seem somebody has thought of writing a standard protocol for broadcasting some other non-temperature parameter (atmosphere pressure, light, noise level, etc). To a certain extent, nRF Master Control Panel can be used to receive arbitrary data from the Arduino (as float or as integer value), but it’s not suitable for logging and combined with the 16 byte limit it’s quite limited (BT also has a 2 bytes overhead for every field you want to send, hence: 8 bytes device name + 4 bytes temperature + 2*2 bytes of overhead = 16 bytes). If I’m wrong, let me know!

I hope you enjoyed this article!

Testing the 111701, a cheap DC-DC booster module for Arduino

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The 111701 is a DC-DC switching booster module that can handle an input between 1 and 5V, and has a fixed output of 5V. It can be found on dx.com and it is the cheapest switching module of its kind I could find, currently priced at 1.47€. Unfortunately I couldn’t find any docs about this module, so here is some of my tests.

The first thing to know about this module is: never reverse the polarity. Things get really hot really fast.

Some specs I gathered:

  • Size: 2.6 cm x 1.8 cm x 0.6 cm
  • Input: 1-5V
  • Output: 5-5.36V (see below)
  • Max output current: rated for 600mA (unconfirmed, maximum I got is 420mA for now)

The board also has two screw mounts, not sure about the size (surely less than 3mm, probably 2.5mm). The screws are meant to mount a female USB connector. The board also offers D+ and D- pins for USB purposes; they aren’t wired to anything.

By using 4xAA batteries I measured an input voltage of 5.15V and an output of 5.36V. This might not be a problem depending on your need. Using a single AA battery (input 1.24V) yields a perfect 5.00V. Below is a chart of the input/output voltage I measured.

111701_grafico