Exclusive OR (XOR) operation is true only when the inputs are different.
An XOR may be constructed using combinatorial logic: an OR ANDed with a NAND. But can it be done with even more basic discrete components?
This circuit uses a diode-bridge and a single transistor - quite neat. It does mean however that there is no output buffer, in fact the output is powered from the inputs. I'm using an Arduino to drive the (more...)
Another way to measure temperatures, this time the DS18S20 - an inexpensive 1-Wire digital thermometer with a range of -55°C to +125°C, at ±0.5°C accuracy from -10°C to +85°C.
It comes in TO-92 packaging and may be powered directly (using three pins), or take parasitic power from the data line (using two pins). This makes it ideal for pin-starved microcontrollers that need a decent ambient temperature reading. In this project, I'm just exercising the (more...)
I'm planning to build a controller that needs motion detection, so got hold of an Invensense MPU-6050 3-Axes Accelerometer Gyroscope Module to see if it would do the trick. The module conveniently operates on 3-5V. All I've done so far is a simple sketch to confirm I can read raw values from the MPU-6050 using the Arduino Wire library.
Buck converters are switching power supplies configured such that the output voltage is lower than the input voltage.
Since the primary components (inductor and capacitor) ideally consume no power, high conversion efficiencies are possible. In practice of course, components are not ideal and there is some power loss. More significant however is any power consumed in the control and feedback circuits.
This circuit is a demonstration and exploration of the basic buck configuration with a (more...)
Can you trust your agile planning process to deliver the best result over time?
In an ideal world with a well-balanced and high-performing team, theory says it should all be dandy. But what happens when the real world sticks it's nose in and you need to deal with varying degrees of disfunction?
Feature Lifecycle Analysis is a technique I've been experimenting with for a few years. The idea is to visualise how well we are (more...)
Can I build a program for the OSHChip using the gcc toolchain and Nordic Semi SDK on MacOSX?
Here are my notes and scripts for compiling and deploy a simple program, but there remain a few rough edges. There are probably easier ways to do this ... like using the Official Yotta target for OSHChip using gcc ... but I was curious to see how far I could get with just gcc and the Nordic (more...)
There are many super-cheap buck converter modules available, often based on the LM2596S-ADJ. The "BuckConverterModules" project is where I've recorded notes on the individual units I get to see. So far I've tested four. Two perform really well; two are OK but I have my doubts about the specs of the converter chip.
This is a super cheap amplifier kit built around the TDA7297 15+15W dual bridge amplifier chip. All the other parts in the kit are essentially the basic supporting components for the TDA7297.
Performance is very good, although my impromptu speaker boxes don't do it justice. They need better baffles at least, but I can hardly blame Straits Preserves for not making marmalade boxes to the specification of speaker enclosures!
I found this interesting LED display at Sim Lim Tower, and grabbed one to test. The LED unit combines 7 x 7-segment display (no decimal points) and 7 indicator LEDs (Red-Green-Yellow).
It is marked as "72R02PHIL T9717". I have no idea what that means(!), and of course there's no sign of a datasheet on the net, so pinouts needed a bit of reverse-engineering. All in all, an interesting display unit for a combination of (more...)
I keep finding new uses for GitHub Pages - situations where in the past I would otherwise have spun up a web site on heroku or similar. But if the site can be static, and especially if you are already hosting the git repository at GitHub, Pages are perfect.
For a long time, I've maintained the LittleArduinoProjects project index as a simple table in the README. But it wasn't particularly nice or usable, so I (more...)