10 replies to abbot binary optionsn
I have already reviewed the Abbott FreeStyle Libre continuous glucose monitor, and I have hinted that I already started reverse engineering the protocol it uses to communicate with the Windows software. I should also point out that for once the software does provide significant value, as they seem to have spent more effort in the data analysis than any other part of it.
Please note that this is just a first part for this device. Unlike the previous blog posts, I have not managed yet to get even partial information downloaded with my script as I write 10 replies to abbot binary optionsn post this. Indeed, if you, as you read this, have any suggestion of things I have not tried yet, please do let me know.
As it is to be expected, the amount of data in these transactions is significantly 10 replies to abbot binary optionsn than that of the other glucometers.
The device itself presents itself as a standard HID device, which is a welcome change from the craziness of SCSI-based hidden message protocols. The messages within are of course not defined in any standard of course, so inspecting them become interesting. 10 replies to abbot binary optionsn took me a while to figure out what the data that the software was already decoding for me meant. Luckily for me, after managing to query the device with python-libusb1which was quite awkward as I also had to fix it to work, I realized that I was essentially reimplementing hidraw access.
Indeed the device seem to respond to two general classes of commands: Text commands also have the same checksumming as both the Optium and Neo protocols. The messages are always transferred in bytes packets, even though the second byte of the message declares the actual significant length, which can be even zero.
The remaining of the protocol kept baffling me. Some of the commands appear to include a checksum, and are ignored if they are not sent correctly. I have thus decided to stop trying to send random messages to 10 replies to abbot binary optionsn for a while.
I have not been pouring time on this as much as I was considering doing before, what with falling for a bad flu, being oncall, and having visitors in town, so I have only been looking at traces from time to time, particularly recording all of them as I downloaded more data out of it. There is a stable conversion between the two units you multiply the former by 18 to get the latterbut this conversion usually happens on display. The exported file is a comma-separated values file, which includes all readings, including those by the sensor, rather than just the spot-checks I could see from the device interface and in the export report.
Now I had something interesting to search for: I already started writing a set of utilities too rough to be published though to convert those into a set of binary files easier to bgrep or binwalk them or hexdump-like transcripts easier to recognize strings.
Because of the way that works, of course, it is not completely obvious if any value which is not a single byte is present, by looking at the text transcript, as it might be found on the message boundary.
10 replies to abbot binary optionsn even after finding one the question was to figure out the record format. I made a mistake with the screenshot by not keeping the command this was a reply to in the picture — this will become more relevant later. Because of the size limit in the HID-based framing protocol Abbott uses, many commands reply with more than one message — although I have not understood yet how it signals a continuation — so in this case the three messages separated by a white line are in response to a single command which by the way is neither the first or the last in a long series.
The first thing I wanted to identify in the response was all the reading IDs, the one I searched for is marked in black in the screenshot, the others are marked in the same green tone. As you can see they are not all sequential; the values are written down as little-endian 10 replies to abbot binary optionsn the way. The next step was to figure out the reading values, which are marked in pink in the image.
Following from that, I needed to find an important value, as it could allow decoding many other record types just by being present: The good thing with timestamps is that they tend to stay similar for a relative long time: Now, since I have the exported data I know not only the reading ID but also the timestamp it reports it 10 replies to abbot binary optionsn, which does not include seconds. I also know that since the readings are usually taken at 15 minutes intervals, if they are using seconds since a given epoch the numbers should be incrementing by between readings.
Knowing this and doing some mental pattern matching it became easy to see where the timestamps have been hiding, they are marked in blue in the image above. At this point, I still have not figured out where the record starts and ends — from the image it might appear that it starts with the record ID, but remember I took this piece of transcript mid-stream.
What I can tell is that the length of the record is not only not a multiple of eight the bytes in hexdump are grouped by eight but 10 replies to abbot binary optionsn is oddwhich, by itself, is fairly odd pun intended. This can be told by noticing how the colouring crosses the mid-row spacing, for 0c 80for reading values and timestamps alike. Even more interesting, not only the records can cross the message boundaries see record 0x8fe0 for which the 0xb value is the next message overbut even do the fields.
Indeed you can see on the third message the timestamp ends abruptly at the end of the message. Since the device uses little-endian to encode the numbers, the higher bytes are at the end of the encoded sequence, which means 4B B5 DE needs to terminate with 05just like CC B8 DE 05 before it.
But the next time we encounter 05 is in position nine of the following message, what gives? The first two bytes of the message, if you checked the protocol description linked earlier, describe the message type 0B and the number of significant bytes following out of the usb packetin this case 3E means the whole rest of the packet is significant.
Following that there are six bytes highlighted turquoise in the imageand here is where things get to be a bit more confusing. You can actually see how discarding those six bytes from each message now gives us a stream of records that are at least fixed length except the last one that is truncated, which means the commands are requesting continuous sequences, rather than blocks of records. Those six bytes now become interesting, together with the inbound command. The command that was sent just before receiving this response was 0D 04 A5 13 00 Once again the first two bytes are only partially relevant message type 0Dfollowed by four significant bytes.
But A5 13 is interesting, since the first message of the reply starts with 13 A6and the next three message increment the second byte each. Indeed, the software 10 replies to abbot binary optionsn these with 0D 04 A9 13 00 00which matches the 13 A9 at the start of the last response message. What the other four bytes mean is still quite the mystery. My assumption right now is that they are some form of checksum.
The reason is to be found in a different set of messages:. In this set of replies, there are two significant differences compared to the ones with record earlier.
The first is that while the command lists 5F 13 the replies start with 10 5Fso that not only 13 becomes 10but 5F is not incremented until the next message, making it unlikely for the two bytes to form a single bit word. The second is that there are at least four messages with identical payload fifty-six bytes of value zero. And despite the fourth byte of the message changing progressively, the following four bytes are staying the same.
By the way, the data in the last message relates to the list of sensors the devices has seen — 9ep. Going back to the epoch, which is essentially the last thing I can talk about for now. The numbers above clearly shower in a different range than 10 replies to abbot binary optionsn UNIX timestamp, which would start with 56 rather than So I used the same method I used for the Verio, and used a fixed, known point in time, got the timestamp from the device and compared with its UNIX timestamp.
The answer was — which is T It turns out that I practice sport often to keep my diabetes type 1 under control. It is not very handy when participating in a race that you have to stop or risk not to do so while testing blood glucose on a bike ride. However, since the data read out from the Libre is not standardized anywhere, I was wondering if you actually ended up finding out 10 replies to abbot binary optionsn coding of the data 10 replies to abbot binary optionsn the Libre.
Thanks a lot in advance! Good blog by the way! I have not even tried reversing the NFC protocol — somebody did but I have no intention to follow through myself. The 10 replies to abbot binary optionsn is that the calibration happens on the reader device rather than the sensor, so even if you can get the data out, it would not be reliable.
For this kind of usage, a continuous 2. HiI finally have a device on my own and I was digging 10 replies to abbot binary optionsn the protocol a little. I found out that with the commands from insulinx https: Now if there is just 10 replies to abbot binary optionsn command which returns the rest as well and we are happy. But 10 replies to abbot binary optionsn is already a step.
Oh wow this is really nice information! Thank you very much! Hi good night dear. I am from Brazil and want help this project. I get a sensor and i am testing read sensor. Can you tell me how interpret raw data. I identificated some lines… but have much data that I dont know what is.
Can you help me to make this? I want implement a bluetooth reader to this sensor. To dont need put smartphone in the arm to read sensor at night, and to generate alarms. I found some values freom freestyle a2 85 0d 59 9e a2 is a glucose meter. For my project http: Does it make sense to start this work based on your current github project?
I have not pushed the mostly-working driver to glucometerutils yet, I plan on doing it this week after I manage to remove a couple of known bugs. You are commenting using your WordPress. You are commenting using your Twitter account. You are commenting using your Facebook account.
Notify me of new comments via email. Notify me of new posts via email. Flameeyes English10 replies to abbot binary optionsn Previous Post CGM review: Next Post Travel cards collection. Of couse I will wait for your driver. Big thanks for sharing! Good work needs time!
Thanks for making this world a better place! Leave a Reply 10 replies to abbot binary optionsn reply Enter your comment here