… in the form of small boxes ūüėČ

Today the long-awaited batteries have finally arrived. Unfortunately, parts are still missing, but you can already see the final size of the device!


One more Question…

… could be answered now.

Actually even three:

  1. There is always the question, how to fix the blueReader on the arm/body?
    So far, I have made little mention of this because we were not yet close enough to the final product to make sure what can be done and how. But now, with the 0.2.0 prototype since Sunday on my arm, I can start making some statements:

    • Using adhesive tape, simply fix the blueReader on the skin with an approximately 15cm long strip of adhesive tape. Depending on movement and clothing, however, it can pull quite strongly on the skin, which leads to skin reactions for me.
    • Magnets, more precisely neodymium magnets. A small strip of tape on the skin, 1 Neodym on it, A strip to save it:
      Another below the blueReader:
      And Voila, the blueReader hangs securely on the arm:
      It has been now for about for 24 hours hanging there without problems. Thanks to Jörn and the LimiTTer users for the tip!
  2. How long does it last with one load?
    I still can not answer this very precisely because of different software problems. In the current firmware was still a bug which under certain circumstances did not put the nfc part to sleep, which of course shortens the run time extremely. Even, if after 5 minutes¬†the next scan switches it off again, an enormous amount of energy is¬†wasted. Now without the bug I’m just at 48h without charging with the double-sized Lipo.
  3. And of course the question that is asked the most: When does my blueReader come to me?
    Unfortunately probably not this year. We still have no batteries and we are still waiting for the charging coils. Two of my three orders are currently stuck in the Netherlands in import¬†handling, no details when they¬†will move¬†again. Even if the deliveries should be done by¬†next week, we need more than 2 days to finish, test, load and embed¬†a blueReader, the silicone needs to be most of the time as it has to harden out. We will probably send the first devices starting in¬†early January, if there are¬†be no further delays with the components deliveries…

Step by step…

… it continues!

Since yesterday evening, I now wear a prototype, based on the 0.2.0 blueReader Board! Why not 0.2.1? Because there is still something wrong: / but we will get to this in the next days, probably only a Diode was put the wrong way onto the mainboards.


Ops¬†this looks huge¬†again! It is huge! But this is not the final product ūüôā

Since we were still waiting for the batteries and the transmitter coils, I had to use a conventional USB charger and a larger battery i had in stock.

On the last picture, you can see the bulge of the big battery on the right, and you can see that the battery adds 1.5cm in width. Also the charger can be see, and how it doubles the height of the board!

Since I do not want to pour this prototype in silicone yet, the antenna is glued on a strip of plastic and is already flexible!

Overall, despite the large battery and the additional charger, the prototype is significantly lighter and smaller than the one I had worn so far. The previous one was built with the Adafruit BLE uart friend, Adafruit Lipo Charger, a bm019 module and a 240mAh lipo.

In addition, I was able to cut the power consumption by 50% again! Below 1.5mAh, the system now consumes, despite it is permanently connected to the smartphone and maintains an encrypted connection. If we find the error on the 0.2.1 boards, the standby current might even drop to 0.6mAh!

Furthermore, the stability of the connection is significantly better as it was with the unencrypted prototype. If I remove the mobile phone from the about 3m reception Radius of the new prototype and then enter it again, the connection is again immediately rebuilt! This is an enormous plus in comfort. So far I had under Android always the problem, whenever I lost reception, I had to search again from within xDrip for the Prototype, which was very annoying, because the Adafruit module ranged only about 1m…

Now I’m curious how long the battery will last and what conclusions I can derive¬†from the data¬†for the blueReader.

The test settings are currently: Every 5 minutes, half of the sensor data is read and a LimiTTer compatible value gets calculated from the data and sent to xDrip.

I hope that this prototyp¬†will last 4 days with¬†one¬†charge of the large battery, even if I’m not sure about how healthy the battery is, since it has deep discharged already a few times …

How does it go from here?

  1. Waiting for the missing coils and rechargeable batteries …
    How long it will take, only the parcel services know, however they do not tell us…
  2. Writing firmware for libBlueReader …
    Since now all basic functions are implemented, except for the voltage measurement for battery monitoring, now my main task is to write the communication libraries for the blueReader and the corresponding integrations for Android and iOS.
  3. Test casting
    This week we will also embed the first devices into silicone, so that we can proceed very quickly with the production, as soon as the missing parts do arrive.

So far so good ūüôā Let’s see what happens next…


And again a step further…

Small happy update:

The average energy consumption has fallen to 3.08mAh ūüôā

So that would be at least 32h operational time!

It goes on and on ūüôā

The next step…

Here is a new update!

What happened since the last entry?

  • We have produced and soldered¬†the first boards of the version 0.2.1: We are now producing stripes with 6 boards which then go into the assembly. The back is soldered in a reflow oven, the front with hot air. On this strip, there were still problems with the solder mask, so only the middle 4 boards were equipped, but this is already a good result for the first attempt. 3 of the 4 boards worked as expected after the assembly, one ¬†seems to have a small short-circuit after¬†soldering.
  • I was finally able to optimize the energy consumption of the software:
    A blueReader waiting for a connection.
    A blueReader that has an encrypted connection to a smartphone and waits for commands.
    A blueReader that has turned on the NFC chip and reads a tag.What can be derived from the numbers? The chosen¬†battery has 100mAh charge, so you would be able to¬†scan 2h without interruption. This is nice but little helpful, just as little as being 26h connected with a smartphone. With a few optimizations it should be possible to get¬†over 24h connection with a scan every¬†5 minutes ¬†ūüôā
  • We are still waiting for the ordered batteries, unfortunately, December is not the best¬†month to get goods from China to Germany. But we still hope that we will receive a few within the next few days.
  • A further construction site is just the wireless charging.¬†There we are also¬†waiting for parts to increase the efficiency. Currently, it would take about 2-3h to recharge the battery wirelessly, but that is not the maximum¬†and we hope to reduce the time to about an hour

So everything goes on, even if I currently have less to report on the progress here ūüôā

Maybe I can give the next update surprisingly within the next, if all parts get delivered and works as intended!