LEAP#425 Look Inside a 7-segment with the Boldport 3×7

A lovely PCB and classic Boldport instructions(!):

This project is a challenge to construct.

The Boldport 3x7 is essentially a 3-digit common-cathode 7-segment display, rendered with discrete components.

Since it’s a chance to look inside the workings of a 7-segment display unit, I decided to modify my build to flip the lid and expose the internal wiring for inspection. Now it’s built, more projects to follow!

As always, all notes, schematics and code are (more...)

LEAP#423 The Maker UNO

I was recently shown an Arduino-compatible board made by Cytron in Penang, Malaysia called the Maker UNO. I gather it began life as a very successful kickstarter that aimed to produce a better board and associated teaching materials for K-12 education.

It packs some nice additional features in the Uno form-factor:

  • LEDs on all digital pins
  • a piezo buzzer on pin 8
  • a push-button on pin 2

Aside from looking pretty spiffy, a really nice (more...)

LEAP#422 VL53L0X Laser Tape Measure

The VL53L0X is a very small Time-of-Flight (ToF) ranging sensor. It is quite widely available as a module, including from Adafruit - see their information page.

For this project I’m taking the module for a test drive and building a short-range tape measure with an Arduino and Nokia 5110 display.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

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LEAP#421 LimeSDR First Look

I think I first heard about LimeSDR-USB on The Amp Hour.

I was convinced to jump in and give it a go particularly because of the fully open-source nature of the platform - from hardware all the way to software, including FPGA code.

The unit is suited to research and development in a wide range of areas, but I suspect as I get more into this I will be mainly focused on areas such as (more...)

LEAP#420 CuttleTalk Audio over LiFi

Now I’ve built the Boldport lite2sound, time to test it out. I’m inspired by LEAP#417 SimpleSamplePlayer to attempt some LiFi audio transmission by light.

I’m using the Boldport Cuttle (an AVR/Arduino clone) to transmit an audio sample with an LED, and the Boldport lite2sound as a receiver. The audio out from lite2sound is amplified with LEAP#210 TDA7297 Kit.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on (more...)

LEAP#419 Boldport Lite2Sound

The Boldport Lite2Sound BC is a crafty collaboration with Rare Waves LLC. It uses a photodiode to detect audio-frequencies from light, which are amplified and piped to an audio jack (or optionally to direct line-out).

Best of all - it comes in an Altoids-sized can!

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

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LEAP#418 Hartley Oscillator

The Hartley oscillator is distinguished by a tapped inductor to provide feedback (the Colpitts oscillator uses capacitors).

I got some decent results on a breadboard, even better on protoboard, using a basic Hertley design with RF chokes for inductors and a BJT.

As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub

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LEAP#417 Playing Sound Samples with Arduino

Microcontrollers typically don’t have a lot of on-board memory, so the idea of playing audio samples is generally out of reach without somehow solving the storage issue or delving into synthesised sound.

But it is possible to play (very) short samples. In this example I’m playing an 8kHz, 8-bit sample stored in flash memory, using the PCM library to modulate a PWM output accordingly.

As always, all notes, schematics and code are in the Little (more...)

LEAP#416 Simple Line-follower

Here’s a neat little line-tracking car kit that’s widely available from the usual online sources. There are a number of variations around, but they all share the same essential control circuit.

It is a simple example of the most basic class of Line Follower Robots, using an op-amp comparator as the “brain” to take feedback from left and right light-dependent resistors to control left and right motors accordingly.

If you know someone just getting (more...)

LEAP#415 Testing Nixies with a 555

I found some Nixie tubes at a reasonable price and snatched them up. I’m sure there’s a project waiting for them, I just haven’t figured out what it will be yet - a clock is a bit obvious!

But first to test them out, and I stumbled across a few boost power supplies using a 555 timer. While these may not be the efficient or precise for a “real” circuit, they are certainly interesting enough (more...)