Instead of controlling his temperature and humidity display directly, maker Zaphunk did things a bit differently, driving the temperature of each segment with a Peltier element, or thermo-electric cooler (TEC), to change its color.
Each segment is made out of a thermochromic material, cycling from a black off state to a greenish hue when on, for a device that can—somewhat ironically—show the temperature by changing its temperature.
Ambient conditions are read via a DHT22 sensor, and everything is controlled by a half-dozen Arduino Nanos. This number boards were needed in order to power the nine dual motor drivers that handle the Peltier elements, each of which require two PWM outputs, along with 5 IO pins.
When you buy—or even salvage—limit switches for electronics projects, you expect them to work again and again, producing normally open (NO) and normally closed (NC) signals as needed. Generally, they do work quite well, but if you want to test this functionality for extra assurance, you might want to check out this project by Mr Innovative.
The automated device spins a NEMA17 stepper motor however many times you choose with a rotary encoder, registering the NO and NC signals that are sent to its Arduino Nano controller in response. The unit then gives a pass or fail output via a small OLED screen to let you know if things are operating properly.
If you wear a CPAP (Continuous Positive Airway Pressure) mask to treat obstructive sleep apnea, you may wake up to find that you’ve flung the mask off during the night or adjusted it to the point that there’s a large air leak. To help with this problem, Bin Sun has developed a CPAP monitor that measures air pressure via an MPXV7002DP sensor—often also used to determine the airspeed of RC models.
The device is controlled by an Arduino Nano, and when it detects improper pressure readings in alarm mode, it activates a small buzzer, displaying a “check mask” message. It can also be set up to run in manometer mode in order to observe pressure changes.
More information—including required parts, print files, and code to make it run—can be found here.
After considering the price of helmet-mounted headsets for motorcycle or moped use, YouTuber GreatScott! decided to try making his own. His walkie-talkie prototype consisted of two Arduino Nano boards, using nRF24L01+ transceivers and a small speaker for PWM audio output.
After a test demonstrating wireless transmission, the design was transferred to custom PCBs, programming their ATmega328P with an Uno acting as an ISP. The audio results are, at this point, barely intelligible. Nevertheless, it’s an interesting experiment, showing that this type of communication is possible using the RF24Audio library with an Arduino-based system.
If you think you could do things better, or that he’s missed something obvious, the PCB design is available here, so be sure to chime in on the video’s comments if you have an idea!
When you want to build a walking robot, the normal route is to individually control each leg with a number of servos or other actuators. Maker Jeremy S. Cook, however, took a different approach with his ‘ClearCrawler,’ using only a pair of motors to power eight legs. These legs are divided up into sets of four on either side of the bot, allowing for differential control similar to a tank.
The leg linkage design is based on Theo Jansen’s Strandbeest mechanism, and a clear head is also implemented with a pair of 8×8 MAX7219 LED matrix eyes. Onboard control is handled by an Arduino Nano and an L298N driver board, while an Uno with a joystick shield serves as the user interface. Radio transmission is via two nRF24L01 modules.
You (hopefully) take regular showers or baths, but how much water do you use each time you step into your facilities? If you don’t know the answer, then this monitor by LiamOSM could be just what you need.
The device uses a flow sensor plumbed inline with a shower head, which transmits pulses to an Arduino Nano setup. This Nano, which resides in a nicely 3D-printed enclosure, measures these pulses and outputs the amount of water you’ve used to a 16×2 LCD screen, along with its cost calculated according to your particular utility rates.
Using such a monitor would likely be an eye-opening experience, and the inexpensive flow sensor used here could be a great tool for other projects as well.
Which uses more water – a bath or a shower?
I was recently thinking about this question, and I realized that I don’t actually know how much water is used when I shower. I know when I’m in the shower sometimes my mind wanders, thinking about a cool new projects idea or trying to decide what to have for breakfast, while water is just gushing down the drain. It would be a lot easier to reduce my water consumption if I actually knew how many litres I was using each time!
I did a bit of research, and found that different shower heads can use anywhere from 9.5 litres (2.5 gallons) per minute to less than 6 litres (1.6 gallons) per minute, if you have a flow restrictor installed. A very old shower could use even more water.
I decided to design and build a device that would display the total volume of water used per shower, the cost of the water, and the flow rate. I’ve had this device installed for a few weeks, and it’s really handy to have a live readout of the amount of water being used.
With many LED projects—like clocks—you’ll want to use a diffuser to keep light somewhat even over a wide area. Diffusers, as their name implies, diffuse light, but what if one was to instead use it as the light source itself?
This clever timepiece from Zaphunk does just that, employing an array of UV LEDs to illuminate a photochromic face. In the case of the glowing screen, the material first shines in response to the lit LEDs, then stays ‘on’ after they turn off, showing four numbers and a colon. When the photochromic cover is in use, the filament instead changes color based on the LEDs.
The clock is implemented with an Arduino Nano, an RTC module, and a heavily modified 8-digit 7-segment display, and triggered via the press of a button on top.
This clock uses a custom built 4-digit 7-segment display made from UV LEDs. In front of the display a screen is placed that consists either of phosphorescent (“glow-in-the-dark”) or photochromic material. A push button on the top lights up the UV display which then illuminates the screen for a few seconds so that it starts glowing or changes color which then slowly fades away.
As a gift for friends that operate tours of Prince William Sound in Alaska, maker ‘rabbitcreek’ decided to make a humongous (4’ diameter) tide clock, controlled by dual Arduino Nanos.
One Nano operates the adorable—though very large—otter on the clock’s face via a servo and gear reduction setup that holds a kayak paddle to indicate high and low tides. The other board handles the unit’s RGB LED lighting, which shines the appropriate color to indicate the vast swings in daylight time of that region.
An RTC module for each Nano provides accurate timekeeping—thus proper tide and daylight indications—and a small monitor is used for maintenance tasks. It’s a brilliant build that is certain to delight residents and tourists to the area alike!
How we see colors is an interesting concept, and as a conversation starter about the physics of color and sound, maker Marcin Poblocki created his own ‘Color Instrument.’
Poblocki’s device rotates a wheel of colors around under a TCS3200/TCS230 sensor via a continuous rotation-modded SG90 servo motor. An Arduino Nano then spits out the tone corresponding to the color it senses using a small speaker, allowing for simple songs to be produced according to hue arrangements.
It’s a neat idea that could be taken in many different directions. At the very least, it would certainly spark conversation, perhaps questioning, as noted in the project write-up, why the color pink isn’t included in the natural light spectrum.
Most pools feature a powered pump system to help filter out debris, but what if your water level gets too low? Pumps designed for ‘wet’ operation generally don’t work well when water isn’t present, so Luc Brun came up with an innovative monitoring solution dubbed “BluePump.”
His setup uses an Arduino Nano and an ACS712 sensor to observe both voltage and current, detecting the phase shift between the two. If this shift is too large, this indicates dry operation, and shuts down the pump via a relay until things are resolved.
To complement this ability, BluePump also includes a temperature sensor, an RTC, and a Bluetooth module, allowing it to schedule cleanings as needed, or work under human control via a custom Android app.