TritiLED Flashes for 20 Years on a Single Coin Cell

From  on Tindie blog:


TritiLED Flashes for 20 Years on a Single Coin Cell

Ted Yapo had a small problem. As an amateur atronomer and astrophotographer, he needed a way to mark his expensive equipment so that he wouldn’t trip over it in the dark. Glow-in-the-dark materials were out because of they only glow for a short time, and glow sticks were also less than ideal because of their single-use nature. Tritium light sources would be perfect, barring the small details that they’re radioactive, expensive, and in the US only a few uses are allowed, most are prohibited by law.


So Yapo instead came up with an LED light that can run for not 20 hours, or even 20 days, but 20 yearson a single CR2032 coin cell battery!

TritiLED Flashes for 20 Years on a Single Coin Cell

OKAY 2 Monophonic Synth Kit

 writes on the Tindie blog:


OKAY 2 Monophonic Synth Kit

Take a look at Tindie’s thriving sound section and you’ll see there is no shortage of people making their own electronic music. These devices take many forms, and one interesting take on sound creation is the OKAY 2 Synth DIY Kit. At face value it features 2 octaves of keys, a built-in amplifier along with a 1/4″ line out, and knobs to select the octaves that you’d like to play — but it gets more interesting under the hood.

Oskitone OKAY 2 from oskitone on Vimeo.

What makes it unique by today’s standards is that it doesn’t use any sort of computer or microcontroller, but instead produces sound using an LM555 timer along with other discreet components for monophonic sound. Given its small size, you could use two at once, perhaps combining them via the line out to be further modified in your synth setup!

In case you’re wondering, the original—or nearly so as it’s version 1.1.1—OKAY is also available. It works largely the same as the OKAY 2, but features only a single octave of keys, and doesn’t have an audio output jack.

OKAY 2 Monophonic Synth Kit

Rotary Encoder with I2C Interface and RGB Lighting

From on the Tindie blog:


Rotary Encoder with I2C Interface and RGB Lighting

Makernet Knob’s makes the point that “Rotary encoders are cool but hard to wire into your projects.” Having wired up a custom input device for my computer using an encoder, I can attest to both of these statements. In my case, it took me quite a bit of time simply to figure out how each encoder pin was used!


Rotary Encoder with I2C Interface and RGB Lighting

How Fast is Your Fidget Spinner?

From Ken Olsen of The Maker’s Box:

How Fast is Your Fidget Spinner?

You never know what people will do with your ideas, and it is always fun to see someone do something I would have never thought off with them.  I got a video from someone who built my Programmable Fidget Spinner, and used a leaf blower to see how fast they could get it to go.  Fortunately, they were wearing safety glasses, and no, it didn’t come flying apart.  It did, however, start displaying erratically at about 3600 RPM (the fastest I can get it by hand is just under 2000 RPM).

So, what is going on?  TLDR: I figured it out and fixed it, and here is proof.

How Fast is Your Fidget Spinner?

DRV8818 Stepper Driver Module for 3D Printers

RAMPS compatible driver module based on DRV8818 by Dean Gouramanis:

Screenshot from 2017-11-15 01-01-04

DRV8818 Stepper Driver Module for 3D Printers

The goal of this project is to fit the DRV8818 driver circuit onto the standard 0.8″ X 0.6″ PCB size used in RAMPS 3D printers. DRV8825 drivers are a popular choice for desktop 3D printers, because they can provide up to 2.5 amps peak current. The DRV8818 is a similar IC capable of driving up to 3.5 amps, but the circuit is too large to fit on PCB using regular methods. Also, without a propper heatsink it will overheat.

Schematic, gerbers and mechanical CAD files are shared on GitHub:


DRV8818 Stepper Driver Module for 3D Printers

Tiny ESP32 WROVER pSRAM board

Tiny ESP32 board from the store on Tindie with optional battery header and pSRAM:

Screenshot from 2017-11-15 00-17-12.png

Tiny ESP32 WROVER pSRAM board

It’s a little ESP32 Board. Perfect for controlling or sensing stuff in the real world and sync it to the internet! Despite that it features the ESP32 WROVER Module. This means it got 4MB FLASH and 4MB RAM. That’s an absolute incredible amount of RAM. I honestly have no clue for what I will ever need 4MB in my embedded Projects.

Screenshot from 2017-11-15 00-25-49

Why did you make it?

I wanted a small ESP32 Board with the pSRAM and which works and doesn’t eat your whole time to get it working and find it’s issues and quirks.

I’ve used the CP2102 Serial converter because this is the one, which works the best way to program the ESP32. Even Espressif uses this serial converter on their own dev boards.


What makes it special?

It’s propably the smallest ESP32 Board with pSRAM. Despite the size it’s ideal for battery operation. It uses under 200uA in Deep Sleep mode!


Tiny ESP32 WROVER pSRAM board