Working Arious motion tracker

Working motion tracker from the video game Alien: Isolation

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This motion tracker is not a 100% replica, it contains deviations which are necessary for it to function properly. The motion tracker from the video game is much more practical to build that the one from the movies, so its easier to build.

By using an array of multiplexed Doppler radar modules motion can be registered and the direction can be extrapolated. Distance cannot be measured, but signal intensity can, and by knowing the object size, distance can be approximated from the signal amplitude.
Once the signals are processed, a dot can be displayed on the screen and instead of distance in meters, the distance is represented in decibels which show the received signal intensity.
Additional processing is required to cancel out the motion of the device itself and detect only objects moving relative to the background.

This project was inspired by the 2017 sci-fi contest, so everything here was created from scratch and posted as a contest entry.

GNU GPL license

Team members & tasks:
Dajgoro - Electronics & firmware
Lovro - 3D modeling & mechanical
Ante - Logistics & QA

Arious main board.pdf

First version of the main board schematic.

Adobe Portable Document Format - 244.39 kB - 02/19/2017 at 19:16

Preview Download


LTspice simulation of a custom charging circuit designed for this project that is able to charge NiCd or NiMh batteries and indicate when its done charging. Also there is a low drop linear voltage regulator that can provide 6V for the analog circuits even if the battery voltage drops as low as 7V.

asc - 4.56 kB - 02/17/2017 at 02:20


HB100 preamplifier.pdf

PDF of the HB100 preamplifier scheamtic.

Adobe Portable Document Format - 47.14 kB - 02/17/2017 at 00:12

Preview Download

KiCad project for the HB100 preamplifier module, along with the gerber files.

Zip Archive - 171.17 kB - 02/15/2017 at 00:34



Slightly modified LTspice schematic/sim of the preamp found in the HB100 application note.

asc - 2.62 kB - 02/12/2017 at 19:16


View all 5 files

  • 5 × HB100 module Doppler radar module
  • 1 × 4.8" 320x480 TFT LCD TFT LCD display
  • 1 × PIC18F4550 Microprocessors, Microcontrollers, DSPs / Microcontrollers (MCUs)
  • 1 × SAA1099 Programmable Sound Generator IC
  • 1 × MPC3208 Data Converters / Analog to Digital Converter ICs (ADCs)
  • 1 × CD4051 Electronic Components / Misc. Electronic Components
  • 5 × TL074 Amplifier and Linear ICs / Operational Amplifiers
  • 10 × BC547 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 4 × 2N2222 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs
  • 1 × BC560 Discrete Semiconductors / Transistors, MOSFETs, FETs, IGBTs

View all 31 components

  • Arious 3D model render

    Lovro Dujnić18 hours ago 0 comments

    3D rendered model in original Alien style.

  • Mainboard schematic

    Dajgoro Labinac2 days ago 4 comments

    The first version of the main board schematic is completed and uploaded in the files above (PDF only for now).
    It contains all of the basic functionalities required, but lacks touchscreen support.
    The board supports up to 8 radar modules with the ability to modulate the HB100 supply voltage.
    The PCB should be coming soon.

    If you spot any issues leave a comment below.

  • Quick update

    Dajgoro Labinac3 days ago 0 comments

    - A new render of the model was uploaded
    - 3D printing is still not done
    - Main board schematic are still being worked on
    - FMCW hardware support will be added
    - 8 battery cells will be used instead of 6

  • Partial 3D print + more spice simulations

    Dajgoro Labinac5 days ago 0 comments

    A picture of the current status of the 3D print has been uploaded. The old Doppler radar module has been inserted for demonstration purposes.
    I designed a battery charging circuit that charges the battery with a constant current until they reach a voltage threshold(adjusted with zener) when the charging process is stopped.
    While charging there is also a led indicator, the charging current can be adjusted.
    Also there is a low voltage drop regulator which is capable of providing 6V even if the battery voltage drops to 7V.

  • HB100 preamplifier board + order

    Dajgoro Labinac7 days ago 7 comments

    The HB100 preamplifier board is finished and files have been uploaded.
    The boards have been ordered along with the radar modules.

  • Thoughts about design paths

    Dajgoro Labinac02/13/2017 at 01:45 2 comments

    Since the device in the game is "low tech" I'll try using only jelly bean components to keep the level of technology true to the game/move.

    - Finished the first set of spice simulations for the HB100 preamp, spice file has been uploaded above
    - Model is still far away from being printed, it will take another week to finish printing all of the parts

    - The HB100 application note shows using the LM324 opamp, for lower noise the TL074 could be used, and also running it at a higher voltage
    - Looking on the web, I found a FFT library that seems to be able to work on a PIC18F mcu, so the PIC18F4550 could be used
    - The UTFT LCD used has tons of Arduino libraries, but none that I could find for PIC, I'll have to adapt them to work in plain C on pic
    - For sound effects, I'm considering using the SAA1099 sound chip, LM358 amp and 8 ohm speaker
    - Considering the MPC A/D IC series as A/D converter IC
    - NiMh or NiCd batteries could be used instead of Li-Ion

  • First project steps

    Dajgoro Labinac02/11/2017 at 21:09 0 comments

    First step, designing 3D model and printing first prototype.
    Currently the rough 3D model is completed and parts are being printed.
    Mechanical assembly is the next step.
    As for the electronics, components are being ordered, which includes a set of Doppler modules and TFT display.
    It is not yet decided which microcontroller will be used, current candidates are PIC 18F, dsPIC and STM32.
    A initial test with one doppler radar module was completed, demonstrating that it indeed works.

View all 7 project logs

View all instructions

Enjoy this project?



AKA the A wrote 4 days ago point

One question - have you tried how the plastic wall of the box affect the signal from the module? At 10GHz, a lot of material (including plastics) behave differently...

As for modulating the frequency - it's dependent on the current going through the device. Modulate the power input and the output should be modulated as well.

  Are you sure? yes | no

Dajgoro Labinac wrote 4 days ago point

I don't really know how the plastic will react, but its the only kind of housing I can afford to make. If it will be an issue I'll have to cut holes and cover them with paper or something.

Regarding the frequency, as I wrote below on another reply, I won't be doing that for now before I get the simpler version working, tho the preamp module I designed has its own little regulator for the radar module, so modulating the power supply would just be a matter of tapping the regulators voltage reference. I even set an enable signal which directly affects that, so I might not need any hacking at all to perform that. I might build in such an option in the hardware and let it sit there until I get arround fiddling with it later.

  Are you sure? yes | no

Martin wrote 4 days ago point

Paper would not be that good, especially if it has any chance to absorb moisture. If the plastic of your housing really absorbs too much of the RF energy then try polystyrol, polyethylene or teflon. These have really good RF performance (low losses).

Btw.: I just saw, that you plan to use BC109C. You can just use the more modern cheaper BC549C or BC550C just what is more easy to get.

  Are you sure? yes | no

Dajgoro Labinac wrote 4 days ago point

"try polystyrol"
Thanks for the advice.

"Btw.: I just saw, that you plan to use BC109C. You can just use the more modern cheaper BC549C or BC550C just what is more easy to get."
That was just an Easter egg, wondering if anyone will notice. :D
I will use either the BC5xx or the 2N2222.

  Are you sure? yes | no

Martin wrote 5 days ago point

You write that the detection of distance is not possible. It would be if you can somehow modulate the frequency of the module to some extent, ideally with a triangle waveform. Sinusoidal is also possible, but it is more difficult to evaluate the signal. (FMCW radar principle) Perhaps it is possible to do this with some variation of the supply voltage. Then you get output signals even for a motionless object, the frequency is dependent on the distance. If the object is moving you get different frequencies during the rising and falling portion of your modulation signal. Now the some of the two frequencies gives you the distance and the difference the speed.

  Are you sure? yes | no

Dajgoro Labinac wrote 5 days ago point

The HB100 module uses oscillator which is physically tuned with a dielectric pellet and traces which match the oscillator wavelength.
In a further iteration it could be possible to create a voltage controlled oscillator and maybe use one of those integrated RF amps to boost the signal and create a array of receiver antennas which would all sync up with the main oscillator instead of multiplexing individual radar modules. Something like this might work:

  Are you sure? yes | no

Martin wrote 4 days ago point

I know it is a DRO, but you can even pull (modulate) a crystal oscillator and a crystal has a much higher Q than a DR pellet. So it should be possible.

With not to much inaccuracy you could call the DRO pellet a glorified ceramic capacitor. :-) Normally they are factory tuned by a grounded thick screw, like a worm screw which is placed above the pellet at a distance of some 0,1mm. So at least some mechanical tuning should work, if you place a grounded slug above the pellet on a piezo speaker. Perhaps even a piezo disc from a buzzer alone would work. I don't know the tuning sensitivity (Hz/µm).

In theorie a small plate or metal ring connected to a varicap diode could also work.

This sure requires some experimentation (or research about tuning DRO's), but that truly would qualify as a hack. :-)

Building a phased array antenna instead of individual modules would of course be a great achievement but require good in depth RF/microwave design knowledge and simulation tools. I don't know your technical background.

  Are you sure? yes | no

Dajgoro Labinac wrote 4 days ago point

For start I'll keep this thing simple, its complex enough as it is.
For now I just want to be able to measure the amplitude and angle of incoming signals. Once I have that working I can work on the next version.
Another problem that needs solving is the motion of the device itself, all signals will have to go over the FFT so that the motion of the device can be cancelled.

As for doing the custom device, I am not an RF wizzard, but I would love to try doing something like that. I do have a friend who works at the local uni in the RF lab and he has access to all of the fancy tools and gears for doing such things.

  Are you sure? yes | no

AKA the A wrote 4 days ago point

It (at least theoretically) is possible to get distance measurements from a doppler device... you need at least 2 of them, fairly far apart and the object (or detector) has to be moving. Then it's just slightly more complicated goniometry, that should be capable of providing speed and angle, from consecutive measurements you should be able to count distance.

  Are you sure? yes | no

Dajgoro Labinac wrote 4 days ago point

Oh, thanks!
I'll give it a read.

  Are you sure? yes | no

Ianmcmill wrote 02/12/2017 at 12:57 point

I did some research on those radar modules and I stumbled over a blog article from 2013 where the guy is showing an amplifier for the HB100. The schematics are open source. He also offers ready made pcbs but they are rather expensive compared to the 3€ radar module.$7-USD-doppler-motion-sensor

  Are you sure? yes | no

Dajgoro Labinac wrote 02/12/2017 at 13:19 point

Thanks for the link. The HB100 datasheet also has such schematics.
The pcb-s are not an issue, I will design my own and order them soon.

  Are you sure? yes | no

Martin wrote 4 days ago point

I don't think this circuit at "limpkin" is a good solution. What you want is a very low noise AC amplifier. You do not even need a very defined gain, as you are only interested in the frequency. So an Opamp, especially a rail to rail Opamp is not a good part for this task. Rail to rail amplifiers are normally a compromise per se and OpAmps normally produce more noise.

This is a high speed low distrotion OpAmp (50MHz GBW) for a task needing only a GBW of greater 7kHz. Ampflification of 100 with an upper frequency limit of 72Hz. This high bandwidth increases noise completely unnecessary and makes it expensive.

The amplifier has a quite good noise voltage performance of 4,5nV/SQRT(Hz) but at 100kHz. In the interesting frequency range (10 to 70Hz) it has 50 to 100nV/SQRT(Hz). And the circuit is of quite high impedance to be low noise. 

By the way the symbol of the double OpAmp in the circuit at "Limpkin" is the worst example of such I have ever seen. It is just confusing. Either you have a block symbol of the IC with its pins in the physical layout of the package or you use two individual triangular symbols.

I would use 2 or 3 single low noise transistor stages, AC coupled and also AC couple the input of the comparator. I would probably design the first stage with a gain of 100 and 2 more stages with a gain of 10 to enable higher output swing. But it can be also possible that you can use just two *100 stages. With an RC combination in parallel to the emitter resistor you can adjust the frequency response (filter curve).

You can also use a good low noise microphone amplifier, if you want to use an IC.

  Are you sure? yes | no

Dajgoro Labinac wrote 4 days ago point

I already designed and ordered the amplifier board which is based upon the application note schematic. I will build it and test how it performs.
This is just to have something better than what I have now which is just two bjt-s. Those ended up being bit too noisy. In the next iteration I'll be getting a better opamp and building it all with smd. This first revision of the entire device will be a bit crude, but should be good enough for proving the concept. Also the next model might get a design overhauld, not having to stick with the game prop hosuing.

  Are you sure? yes | no

Ianmcmill wrote 02/11/2017 at 22:49 point

A really cool project. It would be really nice to see the radar setup and it's results!

How about a PiZero?

Thumbs up on this project!!

  Are you sure? yes | no

Dajgoro Labinac wrote 02/11/2017 at 22:52 point

Sure, we(me and my friends) are still putting together a list of parts to order, unfortunately things take a month to arrive from china, so before than the project is stuck only with the one radar module i had from before. If all goes to plan the housing should finish printing in a week.

PiZero could work, but its not necessary. It only needs to draw a static image for bacground, and everything else is just math.

  Are you sure? yes | no

Ianmcmill wrote 02/11/2017 at 23:00 point

Ok, cool. I am not very into coding and UI stuff on Arduinos and TFTs. I know there is the utft library for Arduino which is capable of the stuff needed for this project. Albeit a PiZero might be overpowered, it has the capability to do some nifty screen effects like blur/motion blur. :) And throwing some cool linux boot code onto the screen which could be modified with Wayland Corp. stuff.

  Are you sure? yes | no

Dajgoro Labinac wrote 02/12/2017 at 00:01 point

I won't be using an arduino, I rarely use it. The graphic is rather simple, it consists of straight lines and circular sections, none of those are hard to generate. If I wanted a fancy background I could just draw an image on the PC and turn it into raw RGB data and load it into an flash/eeprom.
As for Wayland Corp, this model is manufactured by Seegson, the competitor company. :D
*Edit: Not actually made by Seegson, only the station was made by Seegson

  Are you sure? yes | no

Ianmcmill wrote 02/12/2017 at 11:38 point

Seegson. Right. I need to do my homework more carefully :)
How long is the range of those doppler radars?

And I would love to print the model already. Did you design it yourself or where did you get it from?

  Are you sure? yes | no

Dajgoro Labinac wrote 02/12/2017 at 12:35 point

The Doppler modules are HB100, and the datasheet says it can detect human walking at range of 15 meters, the ebay sellers claim 20 meters, so its something in that figure. The device from the movies has the same range.
So far I only built a small amplifier with two discrete bjt transistors, and that has lots of noise which limits the range to about 5 meters.
The 3D model is being designed by a friend who is involved in the project (gotta yet to open a account), and its not done yet. Once the design is completed, it will be uploaded here, along with everything else.

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