The Joy Of Properly Designed Embedded Systems

The ages-old dream of home automation has never been nearer to reality. Creating an Internet of Things device or even a building-wide collection of networked embedded devices is “easy” thanks to cheap building blocks like the ESP8266 WiFi-enabled microcontroller. Yet for any sizable project, it really helps to have a plan before getting started. But even more importantly, if your plan is subject to change as you work along, it is important to plan for flexibility. Practically, this is going to mean expansion headers and over-the-air (OTA) firmware upgrades are a must.

I’d like to illustrate this using a project I got involved in a few years ago, called BMaC, which grew in complexity and scope practically every month. This had us scrambling to keep up with the changes, while teaching us valuable lessons about how to save time and money by having an adaptable system architecture.

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Improving Depth Of Field With Only 5 Phones

The hottest new trend in photography is manipulating Depth of Field, or DOF. It’s how you get those wonderful portraits with the subject in focus and the background ever so artfully blurred out. In years past, it was achieved with intelligent use of lenses and settings on an SLR film camera, but now, it’s all in the software.

The franken-camera rig, consisting of five Pixel 3 smartphones. The cameras are synchronised over WiFi.

For the Pixel 2 smartphone, Google had used some tricky phase-detection autofocus (PDAF) tricks to compute depth data in images, and used this to decide which parts of images to blur. Distant areas would be blurred more, while the subject in the foreground would be left sharp.

This was good, but for the Pixel 3, further development was in order. A 3D-printed phone case was developed to hold five phones in one giant brick. The idea was to take five photos of the same scene at the same time, from slightly different perspectives. This was then used to generate depth data which was fed into a neural network. This neural network was trained on how the individual photos relate to the real-world depth of the scene.

With a trained neural network, this could then be used to generate more realistic depth data from photos taken with a single camera. Now, machine learning is being used to help your phone decide which parts of an image to blur to make your beautiful subjects pop out from the background.

Comparison images show significant improvement of the “learned” depth data versus just the stereo-PDAF generated depth data. It’s yet another shot fired in the smartphone camera arms race, that shows no signs of abating. We just wonder when the Geiger counter mods are going to ship from factory.

[via AndroidPolice]

A ‘Do Not Disturb’ Digital Assistant

Flow requires a certain amount of focus, and when that concentration is broken by pesky colleagues, work can suffer, on top of time wasted attempting to re-engage with the task at hand. The Technical Lead in [Estera Dezelak]’s office got fed up with being interrupted, and needed his own personal assistant to ward off the ‘just one question’-ers.

Initially, [Grega Pušnik] — the tech lead — emailed the office his schedule and blocked out times when he wasn’t to be disturbed, with other developers following suit. When that route’s effectiveness started to wane, he turned the product he was working on — a display for booking meeting rooms — into his own personal timetable display with the option to book a time-slot to answer questions. In an office that  is largely open-concept — not exactly conducive to a ‘do not disturb’ workstation — it was a godsend.

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DIY Rocket Mass Heater Build Log For Commercial Greenhouse

[Bigelow Brook Farm] has a cool geodesic dome greenhouse that needs to stay warm in the winter. There are a lot of commercial solutions for greenhouse heating, but if you’re the kind of person who research and develops solutions for aquaponics, a greener solution may have more appeal.

A rocket mass heater is a combination of a rocket stove and underfloor heating. A rocket stove works by having such a strong draft created by the heat rising up the chimney that the flames can’t crawl up the fuel and burn in the open air, creating a controlled burn zone. Unfortunately, with just a plain rocket stove a lot of heat is lost to the atmosphere needlessly. You only need enough to create the draft.

The mass part solves this. It runs the exhaust under the floor and through radiators. This passively retains a lot of heat inside the space to be heated. It’s a bit of a trick to balance the system so it puts as much heat into the space as possible without stalling, which can be dangerous due to carbon monoxide, among other things. Once the balance is achieved the user gets a stove that can burn fuel very effectively and best of all passively.

[Bigelow Brook Farms] have been working on their heater for quite some time. We really enjoy their test driven development and iteration. They have really interesting autopsies when a component of the heater fails and needs replacing. Right now they have a commercial sized operation heated by their latest iteration and it’s completely passive, being gravity fed. Video after the break.

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Automate Git and Upgrade Your Battle Station With a Custom Peripheral

[mfaust] wakes up in the morning like a regular person, goes to work like a regular person, types in tedious commands for his software versioning utilities like a regular person, and then, as a reward, gets his coffee, just like rest of us. However, what if there was a way to shorten the steps, bringing us all closer to the wonderful coffee step, without all those inconvenient delays? Well, global industry is trying its best to blot out the sun, so mornings are covered there. [Elon Musk’s] thinktank proposed the hyperloop, which should help with the second step. [mfaust] built a control station for his versioning software. Raise your cup of joe high for this man’s innovative spirit.

He first laid out all the buttons, LED lights, and knobs he’d like on a panel to automate away his daily tasks. Using photoshop he ended up with a nice template. He laminated it to the top of a regular project box and did his best to drill holes in the right places without a workshop at his command. It’s pretty good looking!

Since this is the sort of thing an Arduino is best at he, in a mere two tries, wired everything up in such a way that it would all cram into the box. With everything blinking satisfactorily and all the buttons showing up on the serial out, he was ready for the final step.

Being a proficient and prolific enough developer to need a control panel in the first place, like a sort of software DJ, he wrote a nice interface for it all. The Arduino sits and waits for serial input while occasionally spitting out a packet of data describing its switch status. A Java daemon runs in the background of his computer. When the right bits are witnessed, a very nicely executed on screen display reports on the progress of his various scripts.

Now he can arrive at the hyperloop terminal during the appropriate work time slot in Earth’s perpetual night. After which he simply walks up to his computer, flips a few switches, glances quickly at the display for verification, and goes to drink some nice, hydroponically grown, coffee. Just like the rest of us.

Simple Clock from Tiny Chip

If you haven’t jumped on the ESP8266 bandwagon yet, it might be a good time to get started. If you can program an Arduino you have pretty much all of the skills you’ll need to get an ESP8266 up and running. And, if you need a good idea for a project to build with one of these WiFi miracle chips, look no further than [Ben Buxton]’s dated, but awesome, NTP clock.

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Bring Doping, Microfluidics, Photovoltaics, and More Into the Home

Can you make a spectrometer for your home lab all from materials you have sitting around? We might not believe it from a less credible source, but this MIT course does indeed build a spectrometer from foam board using two razor blades as the silt cover and a writable CD as the diffraction grating. The coolest part is removing the metal backing of the CD.

mit_experiments_thumbHackaday reader [gratian] tipped us off about the course available from MIT courseware called Nanomaker. It boils down some fairly complicated experiments to the kind one can do in the home lab without involving thousands of dollars of lab equipment. The whole point is to demystify what we think of as complicated devices and topics surrounding photovoltaics, organic photovoltaics, piezoelectricity and thermoelectricity.


Spectrometers are used to analyze the wavelengths of a light source. Now that you have a measurement tool in hand it’s time to build and experiment with some light sources of your own. Here you can see an LED that is the topic of one of the course labs.

If you have a bit of background in chemistry this is a good step-by-step guide for getting into these types of experiments at home. It reminds us of some of the really cool stuff [Jeri Ellsworth] was doing in her garage lab, like making her own EL panels.

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