I have a Beacon skybeacon Forecum 201 which can advertise as iBeacon or as Eddystone (URL/UID). It has temperature and humidity sensors.
In my project I am using AltBeacon library for monitoring and ranging etc. for working with beacons. As in the examples or docs said, I can get extra data from iBeacon by using getExtraDataFields() method.
When I configure my beacon to transmit as iBeacon, the getExtraDataFields() returns 0, so no sensor values. But when I configure it to transmit as Eddystone UID with TLM than I can read that extra fields, and it returns temperature etc (I tested it with other beacon I have, MINEW E7 beacon and works same way, only as Eddyston UID / TLM sensor values are readable)
I checked even in RadiusNetwork Locate app, and it works the same way as in my app (reads sensor values only when advertise as EddyStone).
So is there any way I can read sensor values on Android with AltBeacon for iBeacon advertisement type? Or it can be only read by Eddystone UID/TLM? So what if working with iOS development and receiving iBeacons?
Mapping of sensors for beacon data fields is dependent on the beacon hardware manufacturer's implementation. In the case of the Forecum 201 it appears that the mapping has been done only for Eddystone-TLM. Other beacon manufacturer's like Radius networks do map beacon sensor fields to AltBeacon. AltBeacon has only a single one byte extra data field that Radius uses to expose the battery sensor. (Other manufacturer's like Kontalt.io do the same.) For iBeacon there are no extra data fields in the layout at all, so it is very unusual for sensors to be exposed by a manufacturer in the an iBeacon advertisement.
Bottom line: you will have to use Eddystone-TLM to read the values from an advertisement with this beacon.
Related
How to identify beacon data frame using raw data?
what is adv type in beacon data frame?
iBeacon uses a Manufacturer AD Type (0xFF) and Eddystone uses a Service Data AD Type (0x16).
The full iBeacon format is documented in my answer here
Google has documented the Eddystone layout here
I can encoded an NFC Sticker with a website that will open when I tap it with a mobile phone. For the application I want to use it for I need to be able to expire that link so the user can't just save the URL and use it again. Basically I need to be able to put a random string in the URL that changes each time it gets scanned, such as www.mywebsite.com/TCHQ23, www.mywebsite.com/LQ8FT, ect.
Is this possible with a regular NFC sticker? If not, what kind of device would I use to make this happen? I know there are Arduino modules that can do this, but is there a simpler method or a ready made product that can act as an NFC but have the URL changed by a computer via a USB cable?
Thanks
NFC tags (some) have a feature called "Mirroring". You can mirror the read counter value to the URL, which gets incremented every time you tap it to reader i.e. Every time read command is called, the counter increases by 1. Tags like NTAG 213, NTAG 215 etc have that feature.
Update:
If your requirement is to get a portion of URL to to return random data and on a cheaper tag or sticker then I would suggest considering NTAG 213 tag, which is cost friendly and also have Mirroring feature supported.
If your URL data is http://www.abc#xyz.com then once the counter Mirroring is enabled (read counter must be enabled first) it will look something like
http://www.abc#xyz.com?000001
The last 6 digit value gets increased by value 1,every time a read command is invoked. (000002, 000003, 000004 and so on)
you can refer this link for more info
So your card/device has to present when read a NDEF record with a link in it (A "Well Known Type 1 with a record type definition of type U, etc), this will cause most phones to open a browser automatically
Some details on the Record type needed at https://www.oreilly.com/library/view/beginning-nfc/9781449324094/ch04.html
Most cards have the ability to store some static data, some have as #Adarsh Rotte says have counters, random number generators, crypto, password protection, mirroring (backup) of data, other functions but non of these will help as these custom functions and are card specific and don't / cannot present the data to match the NFC NDEF specification.
There is one type of card that can do this called JavaCard as these can run fully programmable Java Apps. These can be programmed to respond to NFC read request with the right NDEF measure where the URL can be generated on the fly.
There is a github repo with an example Java App to run on these cards that shows how to respond with and NDEF message at https://github.com/OpenJavaCard/openjavacard-ndef.
Watch out for https://github.com/OpenJavaCard/openjavacard-ndef/issues/10 if trying to use this, the default magic AID number is not the right one for NDEF and should be configured at the time you install the App on the Card.
This app emulates the behaviour of an NFC Type 4 spec card.
You would also need to customise it to have the right NDEF payload data with the right generated URL ending.
There are examples of the Card make/model supported by this App listed on the the github pages some are dual interface cards but there are some without the chip contacts and only NFC interface.
Generating the URL ending could be challenging or easy depending on level of security/validation you need.
Starting from a Random String which would be easy to fake because it has no level of validation, to a obfuscated counter, to a public key type encrypted counter.
There are also other solutions to generating the NDEF data with the right URL that don't use a Card and usually require there own power to run.
Some options:-
An Android phone can do what is call Host Card Emulation (HCE) which is very like what the JavaCard is doing, it is pretending to be a NFC Type 4 Card and the response it sends if fully programmable and could be the right type of NDEF message as per the JavaCard.
There are some "Card Reader" Devices that can be attach to a PC/Raspberry Pie via USB can also do HCE like the Android phone. e.g. https://www.acs.com.hk/en/products/342/acr1252u-usb-nfc-reader-iii-nfc-forum-certified-reader/ - this is well documented in the datasheets on how to do.
There are some other "Card Reader" modules that can connect via I2C to Arduino that can do HCE as well. (Technically most Arduino PN532 Chip's which are used in a lot of USB readers as well can do HCE but it is a bit undocumented on how to do it - see section 4 of https://www.nxp.com/docs/en/user-guide/141520.pdf)
There are some other chips that can act as static data NFC devices the also have an I2C interface to write the static data but allow a "pass through" mode to the I2C interface, again these tend to be NFC Type 4 but do some of the HCE type work for you.
e.g. the M24SR04-Y https://www.st.com/resource/en/datasheet/m24sr04-g.pdf can do it
So technically possible with a variety of methods but all not that simple to implement BUT not "Sticker" type format of NFC devices tend to be very simple NFC device as the format restricts the complexity of the hardware contained in them.
I have ESP23 dev kit with micropython firmware esp32-idf3-20200329-v1.12-317-g688323307.
I also have ds18b20 waterproof sensor. datasheet link
I wrote this code for it:
import time, onewire, ds18x20
import machine
from machine import Pin
ds_pin=Pin(19)
ds_sensor = ds18x20.DS18X20(onewire.OneWire(ds_pin))
roms = ds_sensor.scan()
for rom in roms:
print(rom)
It returns tis info:
[bytearray(b'(\xbcN6\x14\x19\x01\xba')]
Before reading temp data from sensor, we first need to use the scan() function to scan for DS18B20 sensors. The addresses found are saved on the roms variable (the roms variable is of type list). scan() function sends request and sensor returns its unique 64-bit serial code.
I used manual here
Today I bought two more ds18x20 waterproof sensors (I don’t know what type of sensor - ds18a20/ds18b20 or else - are they, ‘cause eager chinese manufacturers sealed sensors inside metal bullet too good, so I can’t just look inside).
I tried to run the same code with them, but it returned the following:
bytearray(b'(\xff\xff\xff\xff\xff\xff\xff')
bytearray(b'(\xfe\xff\xff\xff\xff\xff\xff')
bytearray(b'(\xfc\xff\xff\xff\xff\xff\xff')
bytearray(b'(\xf8\xff\xff\xff\xff\xff\xff')
bytearray(b'(\xf0\xff\xff\xff\xff\xff\xff')
bytearray(b'(\xd0\xff\xff\xff\xff\xff\xff')
bytearray(b'(\x90\xff\xff\xff\xff\xff\xff')
bytearray(b'(\x90\xfe\xff\xff\xff\xff\xff')
bytearray(b'(\x90\xf6\xff\xff\xff\xff\xff')
bytearray(b'(\x90\xe6\xff\xff\xff\xff\xff')
bytearray(b'(\x90\xc6\xff\xff\xff\xff\xff')
bytearray(b'(\x90\x86\xff\xff\xff\xff\xff')
bytearray(b'(\x90\x86\xfd\xff\xff\xff\xff')
bytearray(b'(\x90\x86\xf9\xff\xff\xff\xff')
bytearray(b'(\x90\x86y\xff\xff\xff\xff')
bytearray(b'(\x90\x86y\xfe\xff\xff\xff')
bytearray(b'(\x90\x86y\xfa\xff\xff\xff')
bytearray(b'(\x90\x86y\xf2\xff\xff\xff')
bytearray(b'(\x90\x86y\xe2\xff\xff\xff')
bytearray(b'(\x90\x86y\xa2\xff\xff\xff')
bytearray(b'(\x90\x86y\xa2\xfd\xff\xff')
bytearray(b'(\x90\x86y\xa2\xf9\xff\xff')
bytearray(b'(\x90\x86y\xa2\xf1\xff\xff')
bytearray(b'(\x90\x86y\xa2\xe1\xff\xff')
bytearray(b'(\x90\x86y\xa2\xc1\xff\xff')
bytearray(b'(\x90\x86y\xa2\x81\xff\xff')
bytearray(b'(\x90\x86y\xa2\x01\xff\xff')
bytearray(b'(\x90\x86y\xa2\x01\xfb\xff')
bytearray(b'(\x90\x86y\xa2\x01\xf3\xff')
bytearray(b'(\x90\x86y\xa2\x01\xe3\xff')
bytearray(b'(\x90\x86y\xa2\x01\xc3\xff')
bytearray(b'(\x90\x86y\xa2\x01\x83\xff')
bytearray(b'(\x90\x86y\xa2\x01\x03\xff')
bytearray(b'(\x90\x86y\xa2\x01\x03\xfe')
bytearray(b'(\x90\x86y\xa2\x01\x03\xfc')
bytearray(b'(\x90\x86y\xa2\x01\x03\xdc')
bytearray(b'(\x90\x86y\xa2\x01\x03\\')
When I try to read temperature using this values it returns ‘CRC error’.
What can be done? Is the problem with code, or the sensors are failed somehow?
Connect one sensor at a time when you do the scan.
You haven't shared how you're wired the DS18x20 sensor. Make sure its positive power connection is to 3.3V not 5V.
Make sure you've connected a resistor (4.7K should be good) between the data pin of the sensor and 3.3V. OneWire devices absolutely won't work reliably without this resistor - you might see the kind of problem you're seeing.
If you're sure it's wired correctly the next step would be to try it with different firmware, for instance a Dallas one-wire scanner using the Arduino Core. That would eliminate the possibility of problems with the library you're using and MicroPython.
looks like fake sensor
How to tell original from fake DS18B20 temperature sensors
Looks like i'm a fool))
Yes. One 4.7K pull up resistor and it's alive! IT'S ALIVE!!
aaaand whats'up doc?
then we use internal PULL_UP mode we pull up signal only for ESP.
BUT! DS18B20 is microchip too. And the wire for little DS18B20 is like giant radio aerial.
Maybe in my first sensor this problem was solved on hard level.
How does an OS maps USB device with its device driver? I understand that in the interface descriptor of client USB firmware if no class type has been selected for the device then developer has to provide its own device driver.
I am keen to know how OS maps the pluggged USB device with its device driver? Does descriptors in the USB client firmware contains the file name of the custom device driver? Please let me know.
As a hobby, I have done quite a bit of work with the USB hardware, and had these same questions when I first started.
An OS can map a USB device any way it wants. However, to be more precise toward your question, a USB device will, and must return a class and interface code. Granted, that class code can be 0xFF for user-defined, where the device now must require a unique driver.
In my opinion, this is where the USB shines. All USB devices that return a valid class code specified within the USB specification, will and must follow a specific sequence of events and will "work right out of the box" as indicated. However, this doesn't mean that it cannot have extra capabilities.
For example. A pointing device, such as a mouse, will probably always follow the boot protocol when first plugged in. This is the protocol used and specified in the USB specification so that any OS that follows this protocol can use this pointing device. This protocol specifies a simple three (or more) byte packet for pointer input.
Byte Description
0 Button(s)
1 X Displacement
2 Y Displacement
3 (Device Specific) (optional)
Any pointing device that follows the USB specification most likely has this protocol and will use this protocol until told otherwise. This is so any USB capable OS can use the pointing device.
Every USB device also has a vendor, device, and protocol definition. Once the OS has found this device, it can search through its drivers for a driver that can support this device. That driver, once loaded, can then tell the device to now use a different protocol. i.e.: Return a different Input Report.
Here is an example. Let's say that you have a fancy gaming mouse with three directions of displacement (X, Y and Z), and six buttons. As the OS is booting, it probably has no idea how to use that mouse. Therefore, the manufacturer creates the mouse to use the boot protocol shown above until the driver can be loaded. Once the driver is loaded, which knows how to use the three direction displacements and all six buttons, it can tell the mouse, through a Control packet, maybe the SET INTERFACE command as well, to now start sending a different report, now using the full capabilities of the mouse.
So, as along as the device is USB specification accurate, and has a class code not of user defined (0xFF), the device will be recognized, even if it is a minimal use and/or is to show a statement that a driver is needed.
As for giving a file name of a custom device driver, this is all up to the device manufacturer. However, usually this is not that case. Usually, the OS will retrieve the DEVICE DESCRIPTOR which contains the manufacturer, device, protocol, and other fields. It will then match any driver to those fields. If it does not find a compatible driver, it will ask for one.
For example, one of the pointing devices I used with my research has the following few bytes of the 18-byte Device Descriptor:
Offset Field Value
0 Length 0x12
1 Type 0x01
2 Release Num 0x0110
4 Device Class 0x00
5 Sub Class 0x00
6 Protocol 0x00
7 MaxPacketSz 0x08
8 VendorID 0x04FC
10 Product ID 0x0003
...
Notice that it specifies the Vendor and the Product. Using these two values, a compatible driver can be found.
Now, notice that the class code is zero. This is not an error and is a perfectly valid class code, and simply means that the interface descriptor is to be used instead.
So, hopefully with this information, and specifically, the Manufacturer and Product codes within the DEVICE DESCRIPTOR, you can now see how an OS can find the correct driver for any device.
I'm eventually trying to use transparent data transmission to pass messages between the mobile SDK and an onboard device using the A3 API/UART port.
Right now I used DJI assistant to output a timestamp to the API port at 1hz. When I connect a TTL>USB device, I see garbage data coming through. When I connect an oscilloscope with a protocol analyzer, I see one frame every second, but the frame is variable size. The ASCII representation of what does come through is nonsense.
I have double checked that baud is set correctly (and have tried other baud rates). I've made sure the grounding is proper. I've tried probing the pin on the actual A3 port (to remove possibility of EMI on the serial cable). It seems like I'm getting garbage data on the serial line, or I don't know how to decode it properly.
Hi，maybe you can refer to the open-protocol of M100 Link.I think it's difficult to decode the protocol of N3,unless DJI publishes that。