Jason Hreha and I have been working on several projects which share the constraint of being able to build and publish within 10 days. One of these I’d like to share is Truly Fantastic.
Fantastic is a platform for supporting the very best artists with small cash donations.
The idea of microdonations was a present in some forms in the early web, but probably could not be executed well enough without very high volume and technologies to minimize transaction costs.
And there are some folks doing a goodjob on the tipping and gifting front. And of course, assurance contacts incentivize the production of great content and products, but for video content in particular, wouldn’t it be great if viewers of great content could pay only after watching something amazingly awesome?
Our focus was to create a great video experience with curated (and eventually original content) and then buttress this with a highly focused and clean payment flow.
Microwave Motion Sensors for Fun and Profit (HB100 and Arduino)
I read a lot of science fiction and cyberpunk growing up, and I would obsess over certain sci-fi movies, good and bad. One of the latter which I recently have been thinking a lot about is Johnny Mnemonic.
There is a scene in the beginning of the film where he places a device on a door which alerts him to an attack in progress on the other side of the door. I decided to build something similar.
For the microwave sensor, I chose the HB100, it’s just a few dollars and has the range and precision necessary to carry out the task.
Since my processing and logic will be carried out with an Arduino, a simple op-amp circuit is required to amplify the signal to something the arduino can detect. (See page 5 of the design notes.)
After constructing this, I can verify that the signal is being amplified correctly:
The last component necessary to measure precise velocity is a frequency pre-scaler, to divide the frequency of the signal emitted by the HB100 to something in the range of what the Arduino can measure. According to this Frequency Counter library this maxes out at around 8 Mhz. (More information about prescalers: http://www.qsl.net/n9zia/pre/index.html)
At the 10.525 GHz frequency level for my HB100, the rough calculation for velocity is Doppler Frequency = 19.49V (where V is velocity in km/hr).
Putting it all together, it if definitely less aesthetically pleasing than the motion sensor in the movie:
So, let’s output the signal to the serial port. My simple Arduino script:
Rolling motion data! I can detect motion through the wall near my door, and about 30, 40 feet away. Unlike passive infrared, it cannot be fooled by strange heat signatures. And of course, microwaves pass through walls. However, for drone-on-drone warfare, we can definitely expect pretty poor resilience of the microwave signals since it will be quite easy to jam/mask.
I’m a huge fan of Roxy Music and Bryan Ferry. There is some sort of glamorous desperation in many of their best songs. The 70’s is full of transitions. One of my favorite songs is Mother of Pearl; about 20 seconds into it, the song transitions from a raucous party to a sober and reflective ballad.