[ChrisMentrek] shares a design for a simple green LED signal light intended for experiments in “talking” to fireflies. The device uses simple components like PVC piping and connectors to make something that resembles a signal flashlight with a momentary switch — a device simple enough to make in time for a little weekend experimenting.
Did you know that fireflies, a type of beetle whose lower abdomen can light up thanks to a chemical reaction, flash in patterns? Many creatures, fireflies included, are quite curious under the right circumstances. The idea is to observe some fireflies and attempt to flash the same patterns (or different ones!) with a green LED to see if any come and investigate.
[ChrisMentrek] recommends using a green LED that outputs 565 nm, because that is very close to the colors emitted by most fireflies in North America. There’s also a handy link about firefly flashing patterns from the Massachusetts Audubon society’s Firefly Watch program, which is a great resource for budding scientists.
If staying up and learning more about nocturnal nightlife is your thing, then in between trying to talk to fireflies we recommend listening for bats as another fun activity, although it requires a bit more than just a green LED. Intrigued? Good news, because we can tell you all about the different kinds of bat detectors and what you can expect from them.
There are a few things historically difficult to make a robot do. Stairs, of course, are the obvious problem. But realistic blinking behavior is harder than you might think. At first, it might seem frivolous and simple to have a robot blink, but according to Italian scientists, it is both more important and more difficult than you probably think.
Blinking is a nonverbal cue when humans communicate. The post quotes a Finnish researcher:
While it is often assumed that blinking is just a reflexive physiological function associated with protective functions and ocular lubrication, it also serves an important role in reciprocal interaction.
When developing a network-enabled project with the ESP8266 or ESP32, the easiest way to handle WiFi credentials is to just hardcode the access point and encryption key into the program. But that means recompiling the firmware if you ever want to use it on a different network, which isn’t really an option if you’re trying to make something that other people can easily use. If you’re expecting grandma to bust out the UART cable, we’ve got bad news for you.
There are various ways around this problem, but we think the one developed by [Pekka Lehtikoski] is particularly clever. With a simple application, network credentials can be literally “flashed” to the waiting microcontroller by rapidly blinking the flash LED on an Android device. This allows the information to be transferred quickly and easily regardless of the user’s technical proficiency. One could even make the argument that it’s more secure than some of the other methods of doing initial setup, since an eavesdropper would literally need to see you do it if they wanted to steal your encryption key.
[Pekka] has made the source code for the Android application and the “Gazerbeam” library open for anyone who wants to include the capability in their own projects. To pick up the blinking light you just need to add a phototransistor, an opamp, and a handful of passives to your circuit; making this solution cheap enough that you could even use it in a small-scale production run. The concept isn’t limited to network credentials either. Whenever we can hold conferences again, it could be an interesting way to let attendees customize their badge.
Halloween’s on its way and we want to remind you to get started early so you can show us what you’ve got in store for the little ones this year. [Pete] already finished a simple project to spice up the bushes in front of his house. His trio of glowing and blinking eyes will make a nice addition to the bushes in front of his house. Each is made from a pair of over-sized LEDs mounted on popsicle sticks. After passing the leads through holes in the wood, they are soldered to some resistors and cat-5 cable. The conductors are covered in hot glue to help protect from moisture, and then they’re ready to be driven by the ATtiny2313 which uses random numbers to help ensure the blinking doesn’t look timed. Check out the video after the break to see how he did.
This is a great example that you don’t have to take on the most complicated project in the world to be appreciated. But if you’re looking to be remembered for years to come you might want to aim high by building something like the trash-can jack-in-the-box, or a puking pirate.