Blog
New electronics reference sheet. Karl writes – [via]
Our microprocessor reference sheet has been a great success and a valuable resource for many DIY hackers out there. We are proud to introduce an updated version, a second page with ATMegaXX4/Sanguino and a brand new
electronics reference sheet.We now also have the reference sheet in bigger resolutions suitable for printing on both A4 and A3 paper.
New electronics reference sheet - [Link]
listComPorts – Windows command-line tool for USB-to-serial @ todbot blog – [via]
Did you know each Arduino has a unique serial number in its USB interface that you can use to distinguish one Arduino from another? If you deal with multiple Arduinos, knowing exactly which one is plugged into your computer can be a real time-saver. But actually getting at this serial number and mapping it to COM ports can be challenging. For Windows computers, here’s “listComPorts”, implemented both in GCC C code and in VBScript, both available from my usbSearch github repository.
listComPorts – Windows command-line tool for USB-to-serial - [Link]
Light Meter @ Electric Projects – [via]
I was given a Yashica Mat-124G camera and you cannot get batteries for the light meter, so I decided to make one. I already had the analog meter and the small box, so the two were a natural fit. I also used Adobe Illustrator to make a new paper template and scale for the meter. This needs some work and I realize this is not actual lux levels. The trick here is to come up with a scale useful to the camera I will be using it with.
Light Meter - [Link]
open-evse – Open Electric Vehicle Supply Equipment (EVSE) – Google Project Hosting – [via]
Open EVSE is a Open Source Hardware/Software for charging an Electric Vehicle using the standard J1772 protocol. J1772 is used in the latest generation of EVs such as the Nissan Leaf, Plug in Prius and the Chevy Volt.
Open Electric Vehicle Supply Equipment (EVSE) - [Link]
Make parts in Cadsoft Eagle @ Dangerous Prototypes – [via]
Eagle’s popularity is partly due to the sheer number of parts and footprint libraries available for it. Sometimes you can’t find the part you need in an existing library though, and it’s time to make your own. Making a new part in Cadsoft Eagle can be intimidating for new users, but the guide below shows how we make our own Eagle parts step by step.
Make parts in Cadsoft Eagle - [Link]
Arduino CrossFit Timer - [via]
I was looking for, what I thought, was a simple clock/timer design. Something with a remote and a big display that could be read from across the gym and that I could program with up/down counting but also intervals specific to CrossFit like Fight Gone Bad or tabatas. I wanted to incorporate a bell to give it a gym feel and something that could be heard over loud music. This journey took me through many designs, chips, a custom board, wood working and a whole lot of learning!
Arduino CrossFit Timer - [Link]
Ultra-efficient LED puts out more power than is pumped in (Wired UK) – [via]
MIT physicists have managed to build a light-emitting diode that has an electrical efficiency of more than 100 percent. You may ask, “Wouldn’t that mean it breaks the first law of thermodynamics?” The answer, happily, is no.
The LED produces 69 picowatts of light using 30 picowatts of power, giving it an efficiency of 230 percent. That means it operates above “unity efficiency” — putting it into a category normally occupied by perpetual motion machines.
Ultra-efficient LED puts out more power than is pumped in - [Link]
With current transformers, you can measure AC current simply and with a sufficient accuracy, moreover with maintaining of a high safety level thanks to a galvanic isolation.
General purpose AC current measurment, overload and shortcut protection, load drop or shutdown detection and similar application require simple and reliable solution. Current transformers meet all these requirements and they add further bonuses like galvanic isolation, no intervention to a measured circuit and a convenient price.
As we know, one of AC current measurement methods is based on the usage of a current transformer. Alternating magnetic field around a wire lead, which in a continual proportion to a current flowing through a wire, will induce an AC voltage in a measurement transformer. At a suitable construction and a right transformer loading, is the output voltage in a continual proportion to a current in a measured lead. Perhaps the biggest advantage of this method is the fact, that a measuring circuit is galvanically isolated from a measured lead and at the same time, the transformer doesn´t indtroduce any added load neither any influence. If we´d like to go to a detail, the transformer consumes a negligible amount of energy of few tens of mW/10A from a measured lead, which is being lost in the winding and a load of the transformer.
Every current transformer is designed for a certain load, i.e. at a certain load it provides most accurate results. For example for the type AC-1050 it is 100 Ohms. In such a case is valid a transfer ration 1000:1, i.e. to the load flows a 10 mA current at a 10A current in a measured lead. It means, that on a 100 Ohm we will measure a voltage with a value of 1V. Output of a current transformer can be connected to a panel meter, digital voltmeter, oscilloscope or an AD converter input. By using an AD converter, it is also possible to monitor a course of a current and to discover various nonlinearities in a power consumption.
Talema current transformers are top quality components with an outstanding quality / price ratio. Transformers are designed for soldering into a PCB. In our offer you can find more types, up to 100A maximum current. Currently we can offer you type AC 1050 also from the producer´s stock (ca. 8000 pcs) with 1-2 weeks delivery time (standard delivery time uses to be 20 weeks). Detailed information will provide you datasheets at given types.
Precise and price-convenient measuring of AC current - [Link]
The SM72441 is a programmable MPPT controller capable of controlling four PWM gate drive signals for a 4-switch buck-boost converter. Along with SM72295 (Photovoltaic Full Bridge Driver) it creates a solution for an MPPT configured DC-DC converter with efficiencies up to 98.5%. Integrated into the chip is an 8-channel, 12 bit A/D converter used to sense input and output voltage and current, as well as board configuration. Externally programmable values include maximum output voltage and current as well as different settings on slew rate, and soft-start.
Programmable Maximum Power Point Tracking Controller for Photovoltaic Solar Panels - [Link]
Energy harvesting with a photovoltaic cell requires an efficient dc-dc converter that operates with very low voltage inputs and whose output can charge an external battery. The newly introduced LTC3105 meets these requirements.
Sam Davis writes:
ENERGY HARVESTING CAN EMPLOY SURPLUS OR AMBIENT energy to trickle charge a battery that supplies system power. This eliminates the need to for an ac power line-based recharging circuit, which may be impractical in a remote application. Typically, these applications require very low average power, but can require periodic pulses of higher load current. The Linear Technology LTC3105 is intended for these types of energy harvesting applications.
The LTC3105 is a high efficiency dc-dc boost converter (Fig. 1) that has a 250mVstart-up capability. A resistor divider connected between the VOUT and FB pins adjusts the converter output from 1.5V to 5.25V. An integrated maximum power point controller (MPPC) optimizes performance from photovoltaic (PV) cell inputs. The LT3105′s 3mm × 3mm DFN package (or MSOP-12) and very small external components offer a compact solution for energy harvesting.
LTC3105 DC-DC Boost Converter Harvests Photovoltaic Energy - [Link]
