HX7TR RFID Ultrasonic Positioning System
Hx7 is a high speed precision positioning device, using
ultrasound plus 2.5GHZ local link and Wi-Fi rf. It can be used to form a high
resolution positioning network, covering wide area as well as small localized
operation. The hx7tr is a transceiver, it serves as both ultrasonic transmitter and
receiver simultaneously. Any hx7tr may be mobile or stationary, and the
coordinate frame can be dynamic. E.g. quadcopters drones can form coordinate (frame) reference
points in mid air, to allow other drones to work together within that spatial
zone. The hx7tr comes with a high resolution Gyroscope and Accelerometer, the
IMU data is fused into every positioning data block to allow realistic motion
logging. Every device in the ratsnest network knows the distance to the next.
distances including IMU orientation data is relayed to the
user via standard USART TTL or Wi-Fi. All or selected devices have the ability to be hot
spots (access point) or a station on a standard domestic router. I.e. any and
every device can join the internet of things IoT.
- Above: HX7 positioning four point ratsnest illustration
The 4 point hx7tr ratsnest creates 6 scalars which can be turned into
vectors. Similarly 5 point ratsnest results in 9 distance scalars. Every
Hx7tr device in the hx7 network can be accessed directly using an IP
number over the internet.
- Quadcopter Indoor Navigation
- 3D Studio and Filming
- Immersive Virtual Reality
- Automation and Manufacturing
- Robotics Guidance and Tracking
- Speed of sound measurements
- Echo Ranging Level Detection
- Dynamic 3d temperature graphs
- Range up to 14 Meters
- High Precision (typically 2mm)
- Fully wireless
- Standard USART TTL interface
- 802.11 Station via router
- Hot Spot Access point Interface
- Sampling up to 45s/s
The echo ranging feature
During the measurement cycle the echo from the device's
own activity is also logged and recorded. While the system logs ratsnest
distances the distance from each device to its nearest object is also
measured. This data may be used for collision avoidance and etc.
The hx7tr is a modular device it is created by stacking
up modules. The basic unit contains a signal conditioner, processing unit
and synchronizing 2.4GHZ rf module. Additional modules are also available
such as 802.11 link, Wi-Fi link, hot spot access point IoT. Using
extension modules, multi-purpose devices can be constructed for the end
application without soldering or electronic skills.
The hx7 comes with a software bundle written
in visual basic 6 and PYTHON, this software provides access to hx7 data via
USB serial and IP socket client. It also builds 3d coordinates (x,y,z)
from the available ratsnest distances.
Operation and Functions
Each hx7tr device has its own unique identity. When the
device receives a string through its TTL interface, it compares characters
from the "first in the string" up to & (ampersand) to its unique identity.
If there is a match or partial match the device will regard data following
the ampersand as commands (it ignores spaces between commands). The device
ID may be arbitrarily chosen, i.e. a new ID for the device can be entered at any
point. Once it has a new identity it will respond to this new identity.
The evaluation pack comes with a TTL terminal console
with a floating command panel written in PYTHON. The source code is simple
and open. PYTHON programs run on most major operating systems, and
connect to the hx7tr assembly either through wifi (802.11) or a com channel.
Syntax: ID& instruction1 instruction2 instruction3 ...
The above command if entered using the enter key will
call for drone1. If drone1 is in range, unit 1234 will display the
distance from it to drone1 with latency depending on range... from about 20mS
and up. If the IMU is enabled then the Gyro and Acceleration will also be
displayed in the console. For more information about this program.
Command examples and what they do
Given the identity of a device as T1234, the user's TTL string
can look like this:
T1234& ip:0x10:0x60 ig:0x0F ig:0x20
This TTL string will cause device T1234 to put the
hexadecimal value 33 into LSM6DS0 control register and read the content of
hex locations 0x0F and 0x20
Here is another TTL string
T1234& d2.3 f3.5 ca:1234
if in fact the distance from T1234 to the object is 3.002m the
output string returned is
R1234 X1234 A3002
When the device calls itself it returns an echo. Command
d (dead time) and f (flight time) can be used to create a focus envelope
around an object of interest. The nearest object somewhere between 2.3 and 3.5 meters away
will trigger the echo.
Assuming device Tpete is in range
T1234& d:2.3 f:3.5 mu:1234,pete| a:10 as ms
This statement will cause T1234 to return the distance
to the nearest object, and return the distance from device 1234 to device
pete, this cycle is repeated every 10x8.2 mS or 12 times per second.
If distance from 1234 to pete is 10.3 meters and the
object in previous example is still in place the output string is:
R1234 X1234 A3002
R1234 Xpete A10300
The user can rename every device e.g.:
Then for the pete device the output string will look like
Rpete X(x2m,y3m,z4m) A10300
pete is located on the surface of a sphere with the center at
coordinates (2,3,4) With two more coordinates added, pete will have enough
information to compute own position within the reference frames of these
All the devices are linked through RF so they can be
manipulated remotely. To change the name of the device called pete do as
From here on the device named pete will answer to a call
Note that the first letter in the string can't be
changed. It is a part of the system's inner exchange protocol.