Warren Young of Tangentsoft writes:
Experienced audio DIYers are familiar with monolithic linear regulators like the 78xx series and the LM317. Here’s a simplified block diagram of a standard linear regulator, from National Semiconductor’s Application Note 1148
Let’s see… We have an op-amp, a couple of transistors, a voltage reference, and a few resistors. Can we build a linear regulator from these individual components? Yes, we can!
Op-Amp based linear regulators - [Link]
Microchip Technology Inc has introduced a PIC32 Bluetooth starter kit. The kit includes a board with a PIC32 microcontroller, HCI-based Bluetooth radio, Cree high-output multi-color LED, 3 standard single-color LEDs, an analog 3-axis accelerometer, analog temperature sensor and 5 push buttons for user-defined inputs. In addition the PICkit™ On Board (PKOB) eliminates the need for an external debugger/programmer and supports USB connectivity and GPIOs for rapid development of Bluetooth Serial Port Profile (SPP), USB and general-purpose applications. To support Bluetooth audio the starter kit also includes an interface for a plug-in audio CODEC daughter card set for release at a later stage.
Microchip Bluetooth Starter Kit - [Link]
by Joel Williams @ joelw.id.au:
I bought Avnet’s $49 Spartan 3A development board but it was discontinued not long afterward – right about the time when I decided I needed a few dozen more. I’ve since done some extensive research (thanks, Google!) to find a comparable thrifty thrill.
When choosing a development board, consider what you get with it and what you want to use it for. FPGAs are ideal for use with high speed peripherals, and in general it is much easier to buy a board that contains the part you want, rather than trying to add one on later (and inevitably giving up and upgrading to a more capable board).
Cheap FPGA Development Boards – What to look for - [Link]
It’s holiday season and the chances are some of your gadgets will be also be going along for the ride. The ThinkPower mobile charger by Zettaly has been designed to provide essential recharge capability for USB-charged devices when you find yourself any distance from a mains wall outlet. The ThinkPower itself can be fully charged in just 90minutes and once charged its 10,000mAh high-capacity battery pack can recharge any USB-powered gadget. It has been tested with iPhone, iPad, Samsung Galaxy, Nexus, HTC, Moto, LG, GoPro and many other brands of smartphones, tablets, and cameras (for DIY fans its also tested been tested with the Raspberry Pi :). A fully charged ThinkPower has enough capacity to recharge an iPhone 5 over four times.
Speedy Recharger - [Link]
by TONY DICOLA @ learn.adafruit.com:
Have you heard about small Linux-based development boards like the Raspberry Pi or Beaglebone Black, but been confused about which one is best for you? This guide will compare the specifications, performance, power usage, and development experience of four popular Linux-based development boards to help you choose which is right for you!
Embedded Linux Board Comparison - [Link]
Around June of 2012, I had gotten myself into a very bad habit. Instead of carrying my SD card in my camera, I left it sticking out of the side of my laptop, presumably intending to do something with the photos on it eventually. On my flight home from Boston, the predictable thing happened: as I got up out of my seat, the machine fell out of my lap, and as the machine hit the ground, the SD card hit first, and was destroyed.
I was otherwise ready to write off the data stored on that device, but something inside me just wasn’t happy with that outcome. Before I pitched the SD card in the trash, I took a look at what remained – as far as I could tell, although the board was badly damaged, the storage IC itself was fully intact (although with a few bent pins).
Reverse Engineering a NAND Flash Device Management Algorithm - [Link]
ReturnZero published a stroboscope build:
At its heart, a stroboscope is just a rectangular wave generator hooked up to a light source. I wanted a few extra features to make it nice to use:
Ability to set flash rate by either frequency or RPM
Set duty cycle of output without affecting flash rate
- 2×16 for displaying RPM, frequency and duty (one per line, so one will be hidden at any time)
Rotary encoder (with button) for main interface
- When button is not pressed, knob will increase/decrease the value of the selected digit
- When button is pressed, rotating knob will scroll through display digits
Buttons for quickly halfing/doubling thirding/trebling the flash rate
- This is useful for checking that you haven’t hit on a multiple of the rotation rate
Nice beefy output stage for switch big sets of LEDs
DIY stroboscope - [Link]
herpderp shares his waveform generator:
Here is my last project, a tiny waveform generator based on my previous project and some components:
- An AD9834 (DDS chip with sinus/triangle output)
- 2 x AD5310 (10bit DAC: one for the Vpp control, another one the offset control)
- 3 x LM7171 (Fast OPA)
- 3 x LT1616 (switching regulator: +5V, +7V, -7V)
This waveform generator is directly powered by a standard 12V jack and is capable of outputting a 10Vpp signal at 1MHz (between -5V and +5V, sinus waveform, no load). Above 1MHz, the output starts fading, reaching only 9Vpp at 4MHz (maximal frequency). Frequency, amplitude and offset are digitally controlled through the smart TFT.
Three “basic” waveforms are provided: sinus and triangle, coming from the DDS chip (0.1Hz to 4MHz, 0.1Hz step), and PWM coming from the microcontroller (0.1Hz to 1MHz, variable steps).
Tiny waveform generator - [Link]
Spacewrench over at Dorkbotpdx writes:
I had some spare 4-digit 7-segment LED displays and some AT90USB82s, and I’d always intended to do something with them. This was probably the easiest thing! It’s just the AT90 driving the display, with a(t least) 4 wires controlling it: Vcc, GND, MOSI and SCK. (I haven’t written the code yet, but my plan is to make the display accepts characters via SPI and then spends the rest of the time displaying them).
The board has footprints for a 16MHz crystal and USB connector, so you could make it a USB-enabled 7-segment display as well. I stuffed those parts on my test board, but I’m not sure whether the USB actually works. You can power the display from USB, at least, although the video shows it being powered over SPI (which is the same connection I use to flash code).
Standalone SPI 7-segment display - [Link]
Here’s a voltmeter clock project based on a multimeter clock design by Alan Parekh:
I have used three voltmeters and mounted them on a wooden plinth with a clear Perspex cover to give the clock an industrial look.
I have modified Alan’s code to run on PICBasic Pro version 3. I have also added the following.
Switched display On and Off (keeping battery backup as per Alan’s design) but also allows me to turn meters Off in full power mode.
Synchronization to my Master Clock every 30 seconds
Synchronized LED & Re-Synch LED
Synchronization On & Off
Transistor meter drivers
Separate hourly Chime Circuit
Pulsed “tick tock” seconds sound.
Voltmeter clock project - [Link]