LEAP#341 USB Power Supply

I’ve taken apart and had enough “wall wart” power supplies blow up on me .. so perhaps it is about time to put one together instead! Cheap kits are available, although it pays to carefully map out the circuit and understand how it functions, as schematics don’t always match PCB/silkscreen, and components may also vary! The kit I’ve built here works just fine.. As always, all notes, schematics and code are in the Little Electronics & (more...)

LEAP#340 Boldport Club IxpandO

IxpandO is an input/output expansion board based on Microchip’s MCP23017, BoldportClub Project #16. The board design leaves the door open for various configurations. I decided to go initially with the default setup of 8 inputs (switches) and 8 outputs (LEDs), with an Arduino sketch to demonstrate digital output and interrupt-driven input. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

LEAP#339 PT2399 Delay Kit

I have been reading up on the PT2399 echo audio processor, and a good way of seeing one action is to pick up one of the many delay effects pedals.

The kit I found is nicely put together with a pre-drilled and decorated 1590B enclosure, and some very nice knobs and smooth pots. The build was a breeze, and results are actually pretty decent. As always, all notes and schematics are in the Little Electronics (more...)

LEAP#338 Going GlowBall!

The Glass Eye Studio “Celestial Super Nova” is quite an awesome piece of glass work … I have no idea how these can be manufactured in any quantity with consistency! Perhaps I should find a class? Glass work seems all the rage these days!

You can buy a base with lighting effects, but where is the fun in that? Here’s a project to make a base for the glass ball. Because it is going to (more...)

LEAP#337 RGB LED Glow with Opamps

For a while I’ve been thinking of ways to generate a pseudo-random rainbow glow on a composite RBG LED. In particular, while avoiding just throwing a microprocessor at the problem! I finally settled on three independent opamp-based triangle wave generators that have a nice drifting phase offset. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub hero_image

LEAP#336 Comparator-based Relaxation Oscillator

A quick test of a classic comparator-based relaxation oscillator, modified for single-supply LM358 OpAmp. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub hero_image

LEAP#335 MCP2200 LED Chaser (just because)

The MCP2200 USB-UART transceiver has 8 GPIO pins. Yes, you read that correctly. With such unexpected I/O capabilities, I feel obliged to do the only responsible thing: blink LEDs. Seven LED outputs and one input for a push-button to control direction of the “chase” sequence. As simple C program using the hidapi and we’re done! As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub hero_image

LEAP#334 Exercising the MCP2200 USB-UART transceiver

The MCP2200 is a USB-to-UART serial converter device. It is getting a bit on the old side, only supporting USB 2.0, and all the software support provided is Windows-only. Nevertheless, I got hold of the MCP2200 Breakout Module to find out more. I was particularly intersted to see how far I could get under MacOSX, including configuration over the HID Interface. The answer is pleasantly: all the way! As always, all notes, schematics and (more...)

LEAP#333 Measure Thy Own Voltage

One of the issues with analogue measurements on the Arduino is that typically we assume an accurate 5V reference, and need to add fudge factors for a calibrated reading. Well, I borrowed some code and re-read the ADC part of the datasheet again, and there is a neat little trick for using the 1.1V internal voltage reference to measure (thus calibrate) the supply voltage. It works, but not without caveats - so although QI, (more...)

LEAP#332 RC Phase Shift Oscillator

Three RC high-pass filter poles add more than 180˚ phase shift on top of the 180˚ contributed by a class A BJT inverting amplifier with enough gain to sustain positive feeback. And that’s all you need to make an oscillator. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub hero_image