LEAP#404 The Arza-matron
I’ve had the other half of the guitar I used for The Fretboard (LEAP#018) sitting on a shelf ever since. It’s almost been thrown out a number of times, but luckily I didn’t as it proved to be inspiration for this last-minute idea for a party decoration.
The basic idea, using as many on-hand parts as possible:
- sound input
- 2 LED strip circuits independently controlled and powered from 12V
- simple Arduino sketch to sample the sound and drive the LED strips with PWM
It worked just fine, although in the process I discovered the sound module I used did not output continuous reading but rather a threshold trigger (so the effect was not as subtle as I planned). Something to fix next time I want to fire this up…
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#402 Rolling with the BoldportClub Pips
The BoldportClub Pips circuit is based on “Dicing with LEDs” by Elektor (December 2006), but with a new PCB designed as only Boldport can (and a flashy red baggie).
The ripple counter toggles through all die states at around 8.8kHz. Diode steering is used to light the appropriate LEDs for each state and reset the count when it gets to “7”. This runs fast enough that it appears all LEDs are on at the same time. hen the button is pressed, the counter stops - this is a “roll”.
This is a similar concept (but quite a different implementation) to the LEAP#229 Dice project, which uses a 555 and CD4017 to also achieve a slow-down effect.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#397 I²C Scanner
This is a simple sketch, inspired by i2c_scanner that simply scans for the presence of addresses in the full 7-bit address space.
This can be very helpful when trying to use I²C modules where the default address is not documented.
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
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LEAP#396 Capacitive Touch Organ
The MPR121 is a capacitive touch sensor. Originally produced by Freescale (now NXP), the part is end-of-life but still widely available, especially on breakout boards.
I wrote some code and built a little penny (5 cent actually) organ to test it out. It implements a simple 12-tone (chromatic scale from C5/523.25Hz) organ:
- on interrupt from the MPR121..
- uses the Adafruit_MPR121 library to get touch state via I2C/Wire
- sounds the corresponding tone with a speak on pin 8
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub
Here’s a quick demo:
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