Hello folks. I’ve been trying to develop a new Moteino variant, one based on the chip. I dubbed it Moteino MEGA since it has significantly more memory, IO and functionality than the 328P. All went well except when trying out with RFM69 radios, I can only transmit but not receive. So I’m writing this post in hope that someone else tried the RFM69 library with an Atmega1284P and has some tips to spare.
Moteino MEGA prototype - [Link]
1,6V rechargeable batteries experience “rebirth” and bring several advantages in comparison to 1,2V NiCd accumulators
Experts in electrotechnics might say, that these are a long-time known batteries invented already by Edison thus being no novelty at all. That´s true but in contrast to older tyes is in technological advance of electrolyte and electrodes so as to reach a substantially higher lifetime that few decades ago.
So what´s interesting about these rechargeable batteries? By one sentence, NiZn cell has an output voltage of approx. 1.65V, what´s about 0.4V more than NiMH/ NiCd cells.
At the same time they´re able to provide a high current, similarly like NiCd/ NiMH cells, that´s why they´re also usable in devices with high current demands (conductivity of Zinc is about 15% than Cd). NiZn cells are easily recyclable and they´re very environmentally friendly. Another benefits:
- energy density of NiZn cells is about a third higher than that of NiCd cells (Wh/kg and also Wh/liter).
- higher voltage (1,6-1,8V) enables to reach a higher voltage of „battery-packs“ with a lower count of cells
- lifetime is comparable with NiCd cells
- no memory effect, trouble-free recharge to 100%
- flat discharging characteristics, average voltage aprox. 1,6-1,7V
It is recommended to recharge NiZn cells by C/4 to 1C current (i.e. for example 500 mA to 2000 mA for a 2000mAh cell) while observing a max. voltage of 1.9V/ cell. It´s not recommended to leave cells at a so called “trickle charging” as overcharging might decrease lifetime of cells. Naturally, like in case of almost all rechargeable batteries, the highest lifetime can be reached at operation on a partial discharge (not to a deep discharge). It´s worth to say, that NiZn are not an ideal replacement into devices with a very small power consumption ( e-g- remote controllers), where still win primary alkaline cells.
In our offer can be found NiZn cells themselves: 4AA2500mWh1.6V BP4 and 4AAA900mWh1.6V BP4 as well as a set – charger + cells (4xAA+4xAAA) NizN Charger + Accu. This charger charges by 500 mA current (AA/AAA) and monitors each slot individually. During recharging a LED at agiven slot blinks slowly (1x/s) and after finishing of recharge it shines continuously. In case of a faulty cell it blinks quickly (4x/s).
NiZn rechargeable batteries – when Nickel and Zinc create a strong pair - [Link]
This is my second encounter with LM3886. I was pleased of the sound this chip produced the first time, so I decided to make another amplifier with it. The schematic is based on the schematic in the datasheet of the chip with minor changes.
50W Power Amplifier with LM3886 - [Link]
In this episode Shahriar presents a tutorial on the design and characterization of a single-stage low-noise bipolar amplifier suitable for audio applications. Given a set of specifications, a common-emitter topology is investigated. The circuit employs a beta-insensitive biasing scheme which is simultaneously optimized for maximum output swing. The small-signal gain of the circuit is calculated and the bandwidth is set for audio frequencies. A non-inverting operational amplifier is used as a second stage to achieve the desired overall gain. The circuit is assembled on a breadboard where the gain and bandwidth are measured and compared with design specifications. As the final experiment, the circuit is used to amplify signals from a microphone.
Tutorial on the Theory, Design and Characterization of a Single Transistor Bipolar Amplifier - [Link]
This video shows one method I use to wind toroidal inductors and transformers. The real trick is often how to hold the toroid core while doing the winding of the wire. The plastic toroid fixture shown is available from http://www.qrpme.com. I also give a few details on how to strip the enamel insulation, and then test the inductor when it is complete. There are many, many useful websites that contain toroid data, including composition, type, size, materials, winding factors, calculators, and more
How to wind a toroid inductor - [Link]
Dave tears down Sony’s first digital camera that used removable media, a 3.5″ floppy drive! The 640×480 resolution 0.3Mpixel 1997 vintage Sony Mavica MVC-FD7
EEVblog #625 – Retro Teardown: Sony’s First Digital Camera - [Link]
The xPico WiFi Shield supports simultaneous wireless LAN client connectivity and access point (AP) functionality. This makes it easy to securely connect to an Arduino microcomputer using web-based tools and interactive applications on smartphones or tablets. Its built-in controller ensures that there is no need for a wireless LAN driver on the Arduino microcontroller to configure wireless connectivity.
The xPico Wi-Fi Shield includes connection management software and a web-based configuration interface to manage connectivity complexity on behalf of the application developer. This significantly cuts down the development overheads for engineers, designers, students and hobbyists who need to quickly add smart Wi-Fi solutions to their Arduino designs.
Lantronix Arduino WiFi Shield - [Link]
This project is a USB to Serial converter using an ATMEL AVR microcontroller. There are two version of the converter, one with SMD parts and another with TH parts. The mcu used is an ATmega8 and USB communication is done using software on AVR mcu. It’s based on the software USB implementation of AVR-CDC. Firmware can be downloaded from the download section of CDC-RS232.
USB to Serial Converter using AVR microcontroller - [Link]
Nanoelectronics research center imec and XIMEA, a progressive creator of machine vision systems, today announced their partnership in integrating imec’s Hyperspectral Imaging (HSI) sensors together with XIMEA’s xiQ USB3.0 camera product line. Exceptional interoperability between camera and sensor’s technology streamlined the success of this integration.
“Combining imec’s hyperspectral sensor with XIMEA’s impressively compact xiQ cameras is a new milestone for us. The high-speed USB3.0 interface includes power supply over USB that removes the need for expensive and bulky frame-grabbers and separate power supplies. It will enable our partners to design and mass-produce extremely compact hyperspectral imaging camera solutions,” stated Andy Lambrechts, program manager for imaging & vision systems at imec.
Imec bring smallest hyperspectral imaging camera to market - [Link]
by Michael Dunn:
Thanks to software engineer and hardware hobbyist Bob Alexander, next time you need a batch of PCBs, make his PCB Shopper site your first stop. Enter your basic board specs, like size, layer count, and quantity, and out pops a list of vendors (from China, USA, Canada, & Germany) along with prices and delivery time (BTW, here’s another Canadian source that hasn’t made his list yet: Bittele/7pcb). The site also has a nice little summary of CAD tools.
pcbshopper.com – Find the cheapest PCB manufacturers - [Link]