The Raspberry Pi took the tech world by storm when it first launched two years ago – after all, what self-respecting gadget lover wouldn’t want a teeny, super-affordable and almost infinitely customisable computer? Imagine if it had more power though; perhaps it could be the ideal pocket-sized gaming machine! Good news: such a super-gadget exists, in the form of the aptly-named Banana Pi.
As the fruity name suggests, the Banana Pi offers a similar concept to the Raspberry Pi. It’s an incredibly small, bare-bones PC, packing in the essentials and not a lot else. It means you’ll be able to customise to your heart’s content – coding specific programmes to carry out functions for your home entertainment systems, or adding different features like cameras – but it also means you’ll need to know what you’re doing if you want to get the best out of either the Raspberry or the brand new Banana Pi.
Banana Pi: The £35 mini PC twice as powerful as a Raspberry Pi revealed - [Link]
Matrix keypads are an excellent way of providing user input data into microcontroller-based systems. Keypads find applications in remote controls, standalone data-loggers, security systems, door entry systems, calculators, microwave ovens, etc. They are usually implemented as pushbutton switches arranged in a row and column matrix format to reduce the number of I/O connections. For example, a 16-switch keypad is arranged in a 4 X 4 matrix format requiring 8 I/O connections. A pressed key is detected and identified by scanning the keypad to look for a short circuit condition between a row and a column wire. The keypad scanning can be done either by polling or by means of an interrupt routine. In the polling approach, the scanning process is repeated in a continuous loop, which results in waste of CPU time. The interrupt-approach is more efficient and it notifies the processor when there is a keystroke. Another approach of interfacing a keypad to the microcontroller is by using a dedicated keypad encoder IC, which further reduces the I/O connections and makes the interface much simpler. In this project, we are building a simplified 16-switch keypad using the MM74C922 encoder chip, which converts a key switch closure to a 4-bit nibble output.
MM74C922N-based encoded matrix keypad - [Link]
Maybe the most well designed reflow oven controller out there @ andybrown.me.uk:
It’s been so long since I had the idea for this project that I can’t remember why I had the idea in the first place. At least I blame it on the passage of time although this engineer is getting on a bit now so it could easily be memory rot on my part. So here we are then, a reflow oven controller. Let’s quickly recap what a reflow oven is for those that are new around here.
The two main processes used in industry to build printed circuit boards are wave soldering and reflow using a very large industrial oven that you probably can’t afford and if you could afford to buy it you probably couldn’t afford to house or run it.
An open-source Cortex-M0 halogen reflow oven controller with TFT LCD - [Link]
At less than 0.5mm thick and requiring as little as 7.5mm2 of PCB area, Powerblock II is TI’s latest innovation in synchronous buck NexFET™ Power MOSFET pairs that is ideal for notebooks, tablets, ultrabooks, desktop PCs, and any other application where an ultra small form factor is a necessity. The Power Block II technology combines superior performance and ease-of-use in the industry’s smallest solution size.
TI’s NexFET™ Power Block II Synchronous Buck MOSFETs - [Link]
Get fit for summer with your own activity monitor from this Adafruit Tutorial!
Keep that New Years resolution of getting fit by staying safe with a neopixel motion activated running band powered by Flora, Adafruit’s wearables electronics platform.
This is the activity monitor you’ll want to wear outside and at the dance club!
Get Fit For Summer With A DIY Neopixel Motion Activated Running Band - [Link]
Bumpy is a DIY mp3 player based on ATMEGA32U4 @ 8MHz and VS1003 for mp3 decoding IC. It’s powered from a Li-Ion battery and Max1555 manages battery charging. TPS2112APW is used to automatically switch between USB and battery power. The design is full open source and materials costs about $58 USD for a single board.
Bumpy is a small homemade mp3 player, with features similar to an iPod shuffle. The entire design is open-source, from the firmware to the circuit board to the 3D-printed case. Bumpy plays .mp3 files off of a micro-SD card. You can load files onto the card then plug it into Bumpy, or plug Bumpy into your computer: it will show up like a flash drive (though it’s a bit slower).
Bumpy – a DIY MP3 Player based on ATMEGA32U4 - [Link]
markqvist @ unsigned.io build a 1200-baud AFSK modem on the popular ATmega328p microprocessor:
MicroModem is an educational and open-source implementation of a 1200-baud AFSK modem on the popular ATmega328p microprocessor. This makes it compatible with all Arduino boards and spinoffs using the 328p (for example the Uno, and the Microduino). Apart from a 328pBased board, you will also need to assemble 17 common electronic components to build the modem. When done, it can be used for things like ham radio APRS, TCP/IP over SLIP, experimentation with mesh-networks, long-range wireless communication with sensors (Or friends! Or strangers!).
MicroModem – 1200-baud AFSK modem on ATmega328p - [Link]
Mastro Gippo writes:
I just finished wrapping up an article about a small project I did in Shenzhen during the HackerCamp with Ian. I hope you find it interesting and feature it!
Making stuff in Shenzhen – The Grillino - [Link]
DC/DC switch mode regulators TRACO will save the most precious substance – energy. And now they´re even more affordable thanks to a lower price and better stock.
Maybe, switch-mode regulators are familiar to you from your own praxis or at least from our articles New switch-mode stabilisers Traco TSRN-1 for positive and negative output or Try the effective replacement for standard 78xx regulators and many other.
Fortunately even in this segment it´s true, that thanks to a still bigger popularity of these regulators their price drops down. Moreover, thanks to our close cooperation with the producer – Traco Electronic AG and still bigger stocks we gain a better purchase price and that´s why a better sale price for you as a result. It´s the most obvious in the most popular versions like for example TSR1-2450 and TSR1-24120 with output voltage of 5V or 12V.And the main difference between series TSR1 and TMA? TSR is a so called POL (point of load, non-isolated) regulator, thus it works as “almost lossless load” (buck converter) regulating output power similarly like classic regulators (7805, 7812), only naturally with a substantially higher efficiency. Similarly excellent is also an output voltage stability at a load variation ( typ. 0,4% / 10-100% load). Series TSRxx has the same max. output current for all output voltages, i.e. for example 5V/1A or 12V/1A. In many applications it can be beneficial that TSR operates with up to 36V input voltage.
On the other hand, series TMA is an isolation DC-DC module with an output transformer operating at high frequency (tens to hundreds of kHz). Advantage of the TMA series is a complete galvanic isolation of an output voltage (so called floating voltage) and that´s why it´s suitable even for power supplying of various measuring probes, AD converters and other devices requiring isolated power supply or elimination of ground loops. Despite a significant advantage in a form of an isolated output this type of DC-DC modules has somewhat worse output voltage stability at a load change (max +-10%/20-100% záťaž). Max. output power is constant for a given series (TMA-1W, TMR-2, TEN3-3W, …) i.e. versions with a higher output voltage provide a lower current.
The most comprehensive overview of available DC-DC and AC-DC modules will provide you the short-form Traco catalogue and datasheets at particular types.
Traco TSR, TMA – when every Watt is precious - [Link]
by John Widder & Alessandro Morcelli :
The application of MEMS (Micro Electro-Mechanical Systems) technology to microphones has led to the development of small microphones with very high performance. MEMS microphones offer high SNR, low power consumption, good sensitivity, and are available in very small packages that are fully compatible with surface mount assembly processes. MEMS microphones exhibit almost no change in performance after reflow soldering and have excellent temperature characteristics.
Basic principles of MEMS microphones - [Link]