A good read from Microchip on the theory behind inverter design connected to grip power. Link here (PDF)
There are two main requirements for solar inverter systems: harvest available energy from the PV panel and inject a sinusoidal current into the grid in phase with the grid voltage. In order to harvest the energy out of the PV panel, a Maximum Power Point Tracking (MPPT) algorithm is required. This algorithm determines the maximum amount of power available from the PV module at any given time. Interfacing to the grid requires solar inverter systems to abide by certain standards given by utility companies. These standards, such as EN61000-3-2, IEEE1547 and the U.S. National Electrical Code (NEC) 690, deal with power quality, safety, grounding and detection of islanding conditions.
Application note from Freescale Semiconductor about microinverter solution develop together with Future Electronics. Link here (PDF)
In recent years, demand for renewable energy has increased significantly. The development of devices utilizing clean energy such as solar, wind, geothermal, and fuel cells attracts more and more attention. Solar energy harvesting is developing fast and will play a more important role as a global energy source. One of the ways to capture solar energy is via photovoltaic power generation systems, which are connected to the grid through power inverters. Therefore, many companies are focusing on development of photovoltaic grid-tie inverters. Freescale offers digital signal controllers, the MC56F8xxx family, that are well suited to ongrid solar inverter designs.
Having a child is perhaps the greatest “hack” a human can perform. There’s no soldering iron, no Arduino (we hope), but in the end, you’ve managed to help create the most complex piece of machinery in the known galaxy. The joys of having a child are of course not lost on the geekier of our citizens, for they wonder the same things that all new parents do: how do we make sure the baby is comfortable, how many IR LEDs do we need to see her in the dark, and of course the age old question, should we do this with a web app or go native?
If you’re the kind of person who was frustrated to see that “What to Expect When You’re Expecting” didn’t even bother to mention streaming video codecs, then you’ll love FruitNanny, the wonderfully over-engineered baby monitor created by [Dmitry Ivanov]. The product of nearly two years of development, FruitNanny started as little more than a Raspberry Pi 1n a plastic lunch box. But as [Dmitry] details in his extensive write-up, the latest iteration could easily go head-to-head with products on the commercial market.
[Dmitry] gives a full bill of materials on his page, but all the usual suspects are here. A Raspberry Pi 3 paired with the official NoIR camera make up the heart of the system, and the extremely popular DHT22 handles the environmental monitoring. A very nice 3D printed case, a lens intended for the iPhone, and a dozen IR LEDs round out the build.
The software side is where the project really kicks into high gear. Reading through the setup instructions [Dmitry] has provided is basically a crash course in platform-agnostic video streaming. Even if a little bundle of joy isn’t on your development roadmap, there’s probably a tip or two you can pick up for your next project that requires remote monitoring.
Quick Charge, Qualcomm’s power delivery over USB technology, was introduced in 2013 and has evolved over several versions offering increasing levels of power transfer. The current version — QCv3.0 — offers 18 W power at voltage levels between 3.6 V to 20 V. Moreover, connected devices can negotiate and request any voltage between these two limits in 200 mV steps. After some tinkering, [Vincent Deconinck] succeeded in turning a Quick Charge 3.0 charger into a variable voltage power supply.
To come to grips with what happens under the hood, he first obtained several QC2 and QC3 chargers, hooked them up to an Arduino, and ran the QC2Control library to see how they respond. There were some unexpected results; every time a 5 V handshake request was exchanged during QC mode, the chargers reset, their outputs dropped to 0 V and then settled back to a fixed 5 V output. After that, a fresh handshake was needed to revert to QC mode. Digging deeper, he learned that the Quick Charge system relies on specific control voltages being detected on the D+ and D- terminals of the USB port to determine mode and output voltage. These control voltages are generated using resistor networks connected to the microcontroller GPIO pins. After building a fresh resistor network designed to more closely produce the recommended control voltages, and then optimizing it further to use just two micro-controller pins, he was able to get it to work as expected. Armed with all of this information, he then proceeded to design the QC3Control library, available for download on GitHub.
Thanks to his new library and a dual output QC3 charger, he was able to generate the Jolly Wrencher on his Rigol, by getting the Arduino to quickly make voltage change requests.
Dastels writes, “In my last post I described how I hacked a 2Mbyte SPI flash onto a Trinket M0 to give it the memory space for CircutiPython of one of the M0 Express boards. This time I supersized an M0 Express board, specifically a Feather M0 Express, although the same hack should work on a Circuit Playground Express.”
Even the staunchest 3D printing supporter would have to concede that in general, the greatest strength of 3D printing is not in the production of final parts, but in prototyping. Sure you can make functional prints, as the pages of this site will attest; but few would argue that you wouldn’t be better off getting your design cut out of metal or injection molded if you planned on putting the part into service over the long term. Especially if the part was to be subjected to rough service in an industrial setting.
While that’s valid advice, it certainly isn’t the definitive word on the issue. Just because a part is printed in plastic on a desktop 3D printer doesn’t necessarily mean it can’t be put into real service, at least for as long as it takes to get proper replacement parts. A recent success story from [bloomautomatic] serves as a perfect example, when one of the gears in his MIG welder split, he decided to try and print up a replacement in PLA while he waited for the nylon gear to get shipped out to him. Fast forward seven months and approximately 80,000 welds later, and [bloomautomatic] reports it’s finally time to install those replacement gears he ordered.
In the pictures [bloomautomatic] posted you can see the printed gear finally wore down to the point the teeth were essentially gone where they meshed with their metal counterparts. To those wondering why the gear was plastic to begin with, [bloomautomatic] explains that it’s intended to be a sacrificial gear that will give way instead of destroying the entire gearbox in the event of a jam. According to the original post he made when he installed the replacement gear, the part was printed in Folgertech PLA on a Monoprice Select Mini. There’s no mention of infill percentage, but with such a small part most slicers would likely have made it essentially solid to begin with.