w2aew @ youtube.com writes:
This video describes and demonstrates a fun little circuit that is designed to create a automatically switching, dual-range analog voltmeter which is intended to be built into a variable power supply. By using two ranges, it permits accurately setting a low voltage such as 3.3 or 5V, as well as accurately setting a higher voltage like 24V. Setting a low voltage using a high voltage meter is not very precise, hence the reason I put this together. The circuit is demonstrated, and the schematic is reviewed to describe the operation.
Of course, there are many ways this can be done – this is just one example. It uses one of my favorite little analog ICs, the LM10 op amp and reference. The LM10 (designed by the legendary Bob Widlar) is used as a voltage reference and comparator with hysteresis. A zener diode is used as a shunt regulator. There’s an indicator LED to show when the meter is in the high range, and a 2N7000 enhancement mode n-channel MOSFET is used to change the resistors associated with the analog meter.
Auto-ranging Analog Voltmeter for a variable power supply - [Link]
At the end of this month, I’ll be leaving my current job. I therefore thought it’d be a nice occasion to build a new business card for my future interviews.
AVR business card v2 - [Link]
0xPIT @ github.com writes:
This Reflow Oven Controller relies on an Arduino Pro Micro, which is similar to the Leonardo and easily obtainable on eb*y for less than $10, plus my custom shield, which is actually more like a motherboard.
As I believe it is not wise to have a mess of wiring and tiny breakout-boards for operating mains powered equipment, I’ve decided to design custom board with easily obtainable components.
The hardware can be found in the folder hardware, including the Eagle schematics and PCB layout files. It should fit the freemium version of Eagle
Reflow Oven Controller with graphics TFT - [Link]
Dhananjay Gadre & Nidhi Sharma writes:
Microcontrollers, the heart of all modern electronic gadgets, are increasingly powered with sub-5V power supplies. This complicates the control of external loads powered by higher voltages. The reduced I/O supply voltage leads to increased complexity in handling high-side voltage switching. Figure 1 illustrates the conventional solution for controlling a 5V high-side switch, driven here by a 3.3V signal.
Zener level-shifter drives high-side switch - [Link]
aldricnegrier @ instructables.com writes:
The objective of this instructable is to guide your way throw the entire making process of building a BuildersBot machine. An Arduino controlled CNC Router that can also perform 3D printing.
The instructions will cover all areas such as, mechanics, electronics and software.
Arduino Controlled CNC / 3D Printer - [Link]
This Photodiode based Alarm can be used to give a warning alarm when someone passes through a protected area. The circuit is kept standby through a laser beam or IR beam focused on to the Photodiode. When the beam path breaks, alarm will be triggered. The circuit uses a PN Photodiode in the reverse bias mode to detect light intensity. In the presence of Laser / IR rays, the Photodiode conducts and provides base bias to T1.
The NPN transistor T1 conducts and takes the reset pin 4 of IC1 to ground potential. IC1 is wired as an Astable oscillator using the components R3, VR1 and C3. The Astable operates only when its reset pin becomes high. When the Laser / IR beam breaks, current through the Photodiode ceases and T1 turns off. The collector voltage of T1 then goes high and enables IC1. The output pulses from IC1 drives the speaker and alarm tone will be generated.
A simple IR transmitter circuit is given which uses Continuous IR rays. The transmitter can emit IR rays up to 5 meters if the IR LEDs are enclosed in black tubes.
555 Photodiode alarm - [Link]
Brian Dorey made this DIY USB to RS485 adapter, that is available at Github:
We looked for a full-duplex ready-made adapter but all the ones we found are only half duplex devices and as we needed to be able to supply 12 volts via the RJ45 connectors on the slave boards we decided to make our own USB to RS485 full duplex adapter using a USB converter chip from FTDI.
The board uses an FT230X with an RS485 converter chip which outputs to a set of header pins and also an RJ45 socket.
The new adapter board can supply power to the slave devices through the USB port or can be powered from an external supply by removing a power selector jumper. The board also has an on board 120R terminator resistor with selection jumper and LED’s to show serial activity.
USB to RS485 adapter - [Link]
During SOS webinar with 4D Systems you could find out how graphic processor Diablo 16 can make our work easier and shorten time necessary for the development.
Get to know the performance and user-friendly graphic processor Diablo 16 - [Link]
by Nancy Owano @ phys.org:
Sony’s advance in image sensors appears quite natural: the company has developed a set of curved CMOS image sensors based on the curvature of the eye. A report on the sensors in IEEE Spectrum said that, “in a bit of biomimicry,” Sony engineers were able to achieve a set of curved CMOS image sensors using a “bending machine” of their own construction.
Sony inspired by biomimicry develops curved CMOS sensors - [Link]
by Matt Mcgowan @ phys.org:
Engineering researchers at the University of Arkansas have designed integrated circuits that can survive at temperatures greater than 350 degrees Celsius – or roughly 660 degrees Fahrenheit. Their work, funded by the National Science Foundation, will improve the functioning of processors, drivers, controllers and other analog and digital circuits used in power electronics, automobiles and aerospace equipment – all of which must perform at high and often extreme temperatures.
“This ruggedness allows these circuits to be placed in locations where standard silicon-based parts can’t survive,” said Alan Mantooth, Distinguished Professor. “The circuit blocks we designed contributed to superior performance of signal processing, controllers and driver circuitry. We are extremely excited about the results so far.”
Circuits capable of functioning at temperatures greater than 650 degrees fahrenheit - [Link]