Really, the links are just the tip of the iceberg here as far as the gifts that [Elite Worm] bestows upon those who choose to undertake this project. The build video (after the break, as usual; our favor to you) is fantastic, and would be perfect for a beginner because of the entrancing speed at which he builds it. The video is straight up relaxing to watch, whether you want to build one or not.
It’s a fairly simple circuit — just push the momentary switch, and the laser diode and sensor pair count the revolutions over one second. The Arduino Nano multiplies this number by 60 and displays the RPM on the OLED screen. What we absolutely love about this build is the care that taken in designing the case. There’s a designated spot for each component, and the ones without their own special holder are kept in place with printed crossbar pieces. [Elite Worm] says this has a higher refresh rate than his store-bought tacho, and we say it looks way cooler, too.
The ESP8266 has become practically the 555 chip of WiFi connected microcontrollers. Traditionally, you’d buy one on a little breakout board with some pins and a few connectors, and then wire up anything else you need. The ESP8266’s big brother, the ESP32, hasn’t quite taken over from the ESP8266, but it has a lot more power and many more options. [Andreas] has a new video that shows seven new ESP32 boards that have integral displays. These boards can simplify a lot of applications where you need both WiFi and a user interface.
Of the boards examined, six of them have OLED displays, but one has an E-paper display. To summarize results, [Andreas] summarized his findings on these seven along with others in an online spreadsheet.
Blockchains claim to be public, distributed, effectively immutable ledgers. Unfortunately, they also tend to get a little bit huge – presently the Bitcoin blockchain is 194GB and Ethereum weighs in at 444GB. That poses quite an inconvenience for me, as I was looking at making some fun ‘Ethereum blockchain aware’ gadgets and that’s several orders of magnitude too much data to deal with on a microcontroller, not to mention the bandwidth cost if using 3G.
Having imagined a thin device that I could integrate into my mobile phone cover (or perhaps… a wallet?) dealing with the whole blockchain was clearly not a possibility. I could use a VPS or router to efficiently download the necessary data and respond to queries, but even that seemed like a lot of overhead, so I investigated available APIs.
As it turns out, several blockchain explorers offer APIs that do what I want. My efforts get an ESP8266 involved with the blockchain began with two of the available APIs: Ethplorer and Etherscan.
Calling it the ESPecter, [ACROBOTIC Industries] wanted to make this a simple project for anyone, regardless of skill with a soldering iron or Arduino toolkit. So they decided to base the guts on common components that can be put together easily, specifically a Wemos Mini D1 with an OLED shield as a bright display. They also designed a cool tiltable 3D-printed enclosure for this small device so that you can orient it to your eye level.
[ChrisN219] has an antique Coke machine that used to hold glass bottles. Now it holds around 30 tall boy cans of his favorite post-work suds. The only problem is that [Chris] has no idea how many cans are in it without opening up the door or keeping tally on a nearby slate board. Enter the Arduino.
He wanted to make something completely non-invasive to the machine (phew!) while using as many parts he already had as possible. The result is a simple circuit that uses an ultrasonic sensor mounted inside the machine to ping the depths, and a Nano in a nifty 3D printed box up top to do some math and display the number of cans remaining as a simple bar graph. The sensor reads one bay, and the code multiplies by two to get the total. It was touch and go there for a minute as he wasn’t sure that the HC-SR04s would get a good response from the cylindrical cans. Not only did they give a good reading, the first test was quite accurate.
[Chris] recently finished Mk. II, which replaces the momentary (and the Coke logo) with a second HC-SR04. The first version required the push of a button to do inventory, but now he simply walks up to the machine and knows at a glance if it’s time to make a beer run.
Okay, so maybe you don’t have cool old Coke machine problems. But surely you can find something that needs pinging, like an inconvenient rain barrel.
He threw out everything but the keyboard assembly for the build. Each key press now drives a momentary button, and those are all wired up to an Arduino Mega through some I/O expansion boards left over from another project. The Mega drives the MOS6581 SID chip which generates those sweet chiptunes. There are four CV outs for expanding the organ’s horizons with Eurorack modules.
Our favorite part is the re-use of the stop knobs — particularly that they are actuated the same way as before. The knobs still technically control the sound, but in a new way — now they turn pots that change the arpeggio, frequency, or whatever he wants ’em to do.
The plans for the future revolve around switching to a Teensy to help out with memory issues. Although it’s a work in progress, this organ already has a ton of features. Be sure to check them out after the break.
Once you dive down the chiptunes rabbit hole, you might want to take them everywhere. When you get to that point, here’s a portable SID player. A SIDman, if you will.
[Ash] built Moo-Bot, a robot cow scarecrow to enter the competition at a local scarecrow festival. We’re not sure if Moo-bot will win the competition, but it sure is a winning hack for us. [Ash]’s blog is peppered with delightful prose and tons of pictures, making this an easy to build project for anyone with access to basic carpentry and electronics tools. One of the festival’s theme was “Out of this World” for space and sci-fi scarecrows. When [Ash] heard his 3-year old son sing “hey diddle diddle, the cat and the fiddle…”, he immediately thought of building a cow jumping over the moon scarecrow. And since he had not seen any interactive scarecrows at earlier festivals, he decided to give his jumping cow a lively character.
Construction of the Moo-Bot is broken up in to three parts. The skeleton is built from lumber slabs and planks. The insides are then gutted with all of the electronics. Finally, the whole cow is skinned using sheet metal and finished off with greebles to add detailing such as ears, legs, spots and nostrils. And since it is installed in the open, its skin also doubles up to help Moo-bot stay dry on the insides when it rains. To make Moo-Bot easy to transport from barn to launchpad, it’s broken up in to three modules — the body, the head and the mounting post with the moon.
Moo-Bot has an Arduino brain which wakes up when the push button on its mouth is pressed. Its two OLED screen eyes open up, and the MP3 player sends bovine sounding audio clips to a large sound box. The Arduino also triggers some lights around the Moon. Juice for running the whole show comes from a bank of eight, large type “D” cells wired to provide 6 V — enough to keep Moo-Bot fed for at least a couple of months.
Check out the video after the break to hear Moo-bot tell some cow jokes – it’s pretty funny. We’re rooting for it to win the competition — Go Moo-bot.