Ask Hackaday: How Does This Air Particle Sensor Work?

The hardware coming out of [Dr. Peter Jansen]’s lab is the craziest stuff you can imagine. He’s built a CT scanner out of plywood, and an MRI machine out of many, many turns of enamel wire. Perhaps his best-known build is his Tricorder – a real, all-sensing device with permission from the estate of [Gene Roddenberry] to use the name. [Peter]’s tricorder was one of the finalists for the first Hackaday Prize, but that doesn’t mean he’s stopped working on it. Sensors are always getting better, and by sometime in the 23rd century, he’ll be able to fit a neutrino detector inside a tiny hand-held device.

One of the new sensors [Peter] is working with is the MAX30105 air particle sensor. The marketing materials for this chip say it’s designed for smoke detectors and fire alarms, but this is really one of the smallest dust and particle sensors on the market. If you want a handheld device that detects dust, this should be the chip you’re looking at.

Unfortunately, Maxim is being very, very tight-lipped about how this particle sensor works. There is a way to get access to raw particle counts and the underlying algorithms, and Maxim is more than willing to sell those algorithms through a third-party distributor. That’s simply not how we do things around here, so [Peter] is looking for someone with a fancy particle sensor to collect a few hours of data so he can build a driver for this chip.

Here’s what we know about the MAX30105 air particle sensor. There are three LEDs inside this chip (red, IR, and green), and an optical sensor underneath a piece of glass. The chip drives the LEDs, light reflects off smoke particles, and enters the optical sensor. From there, magic algorithms turn this into a number corresponding to a particle count. [Peter]’s hackaday.io log for this project has tons of data, math, and statistics on the data that comes out of this sensor. He’s also built a test rig to compare this sensor with other particle sensors (the DSM501A and Sharp sensors). The data from the Maxim sensor looks good, but it’s not good enough for a Tricorder. This is where you, o reader of Hackaday, come in.

[Peter] is looking for someone with access to a fancy particle sensor to collect a few hours worth of data with this Maxim sensor in a test rig. Once that’s done, a few statistical tests should be enough to verify the work done so far and build a driver for this sensor. Then, [Peter] will be able to play around with this sensor and hopefully make a very cheap but very accurate air particle sensor that should be hanging on the wall of your shop.

3D Printed Mini-Printer Enables Obsession With Lists

When going about a busy day, a hard copy listing all your tasks helps if you aren’t inclined to pull up a notepad — or whatever app you use — on your phone each time; doubly so if you want to pin it up in one place to refer to. Besides, using a full sheet of paper for a few items is impractical — and wasteful. To that end, [Jed Hodson] has concocted a mini printer for all your listing needs.

[Hodson] designed and 3D printed the case, making the files available for download and instructions on how to assemble it. Being an IoT device, the printer uses a Photon board to connect to the Internet, wherein Microsoft Flow is used to liaise between the Adafruit printer and Wunderlist — the list app [Hodson]’s chosen for this project.

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Train Time Ticker Will Save Your Morning Commute

The fatal combination of not being a early riser and commuting to work using public transit can easily result in missed buses or trains. Frustrated with missing train after train while fumbling with a complicated transit schedule app, [Fergal Carroll] created a Train Time Ticker to help his morning routine run right on time.

A Particle Photon hooked up to a 2.2″ TFT screen — both mounted on a breadboard with a button — fit the purpose tidily. Weekday mornings, the Ticker pulls — from a server he set up — the departure times for the specific station and platform along [Carroll]’s commute every three minutes; at all other times, the Ticker can be manually refreshed for any impending trips.

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Particle Electron – The Solution To Cellular Things

Just over a year ago, Particle (formerly Spark), makers of the very popular Core and Particle Photon WiFi development kits, released the first juicy tidbits for a very interesting piece of hardware. It was the Electron, a cheap, all-in-one cellular development kit with an even more interesting data plan. Particle would offer their own cellular service, allowing their tiny board to send or receive 1 Megabyte for $3.00 a month, without any contracts.

Thousands of people found this an interesting proposition and the Electron crowdfunding campaign took off like a rocket. Now, after a year of development and manufacturing, these tiny cellular boards are finally shipping out to backers and today the Electron officially launches.

Particle was kind enough to provide Hackaday with an Electron kit for a review. The short version of this review is the Electron is a great development platform, but Particle pulled off a small revolution in cellular communications and the Internet of Things

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Hacking a coffee machine

The folks at Q42 write code, lots of it, and this implies the copious consumption of coffee. In more primitive times, an actual human person would measure how many cups were consumed and update a counter on their website once a day. That had to be fixed, obviously, so they hacked their coffee machine so it publishes the amount of coffee being consumed by itself. Their Jura coffee machine makes good coffee, but it wasn’t hacker friendly at all. No API, no documentation, non-standard serial port and encrypted EEPROM contents. It seems the manufacturer tried every trick to keep the hackers away — challenge accepted.

The folks at Q42 found details of the Jura encryption protocol from the internet, and then hooked up a Raspberry-Pi via serial UART to the Jura. Encryption consisted of taking each byte and breaking it up in to 4 bytes, with the data being loaded in bit positions 2 and 5 of each of the 4 bytes, which got OR’ed into 0x5B. To figure out where the counter data was stored by the machine in the EEPROM, they took a data dump of the contents, poured a shot of coffee, took another memory dump, and then compared the two.

Once they had this all figured out, the Raspberry-Pi was no longer required, and was replaced with the more appropriate Particle Photon. The Photon is put on a bread board and stuck with Velcro to the back of the coffee machine, with three wires connected to the serial port on the machine.

If you’d like to dig in to their code, checkout their GitHub repository. Seems the guys at Q42 love playing games too – check out 0h h1 and 0h n0.

Thanks [Max] for letting us know about this.

The Netflix and Chill Button

While the people at Netflix were busy killing weekends around the world with marathon viewings of 90s sitcoms, they also found time to release the Netflix Switch. It’s a small device with a single button that will control your TV, turn off the lights, and order a pizza. Remember, time you enjoy wasting is not wasted time.

netflixThe Netflix Switch is a relatively simple device powered by a Particle Core, an Arduino-compatible development board with on-board WiFi. Also in this box is a LiPo battery, a few LEDs, and an IR transmitter that will send the same IR signal as the Netflix button on your TV remote, should your remote have a Netflix button.

In an unprecedented break from reality, this astute corporate branding of electronics tinkering also has design files, schematics, and real instructions that come along with it. Netflix released all of the mechanical files for their switch in Solidworks format; for the low, low price of only $4000 per Solidworks license, you too can Netflix and Chill.

Although Netflix’ implementation of tapping into a DIY electronics movement that has been around for 100 years is lacking, the spirit of the build is laudable. A single button connected to the Internet is a universal tool, and whether you want to order a pizza or make a ‘do not disturb’ button for your phone, the only limitation for the Netflix and Chill button is your imagination.

The “Effervo” Kinect Particle Effect Machine

Here’s a new hack for the Xbox Kinect called “Effervo”. It’s a really cool effect built using Openframeworks. The Kinect is setup in front of the user and the projector puts an image in front of the user’s screen. Three dimensional data about the person and his or her movements is captured using Microsoft’s sensor. As it is described, the Effervo program “uses simple iterative rules to govern its movement and gives the impression of swarm like behavior.” This may not be a “Haloween Hack”, but we could definitely see something similar used in a haunted house. Maybe it could use blood droplets instead of particles?

Maybe this hack will inspire other people to follow in [Jayson’s] footsteps. He describes himself as a “programmer turned artist.” We’d like to think that all engineering and programming work is a form of art, but the video of this piece in action after the break is especially eye-catching.

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