Tag Archives: Popular Mechanics

This DIY moisture monitor

 will help keep your houseplants alive

With spring just around the corner, it’s never too early to start thinking about planting.

Writing for Popular Mechanics, Alexandra Chang explained why she recently created an open-source, Arduino-powered DIY moisture monitor to ensure that her plants received the optimal living conditions.


“My perennials always died because I watered them too little or too much, or put them somewhere too dark or too hot,” she says. 

“[So] I vowed to keep my plants alive [and] turned to Arduino. I’d been looking for an excuse to try out this microcontroller platform, which I knew could be programmed to do a lot of cool things. Why not use it to save my ailing amaryllis?”

According to Chang, the project took a single afternoon and resulted in a smart sensor that was capable of reading and displaying soil-moisture levels, light intensity and temperature. 

For the build, the Maker turned to no other than an Arduino Uno Starter Kit (ATmega328) which included the following parts:

  • Solderless breadboard ($5)
  • Assorted wires ($7)
  • Thermistor ($2)
  • Photoresistor ($1)
  • 10K-ohm resistors ($8 per pack)
  • Potentiometer ($1)
  • LCD display ($10)


After finding instructions for a number of Arduino-based plant sensors online, such as the GardenBot, the ArduGarden and Soil IQ’s solar-powered sensor, Chang converged certain elements from each to devise something that suited her own skill level and needs.

The DIY gardening device features two soil probes responsible for measuring how much the soil resists the flow of electricity — or how moist it is. By adding a photoresistor (light sensor) and a thermistor (temperature sensor), then connecting them to a programmed Arduino, she was left with a gadget that could monitor the environment of a single plant. Meanwhile, an LCD display was used to show its moisture, temperature, and light readings in variable resistance values.

Interested in learning more? Head over to the project’s official writeup in Popular Mechanics here.

$25 device lets doctors diagnose from anywhere

Remote diagnostics is an emerging field that allows healthcare workers to perform tests on patient samples in the field and to get results interpreted by medical experts remotely. However, providing care in this manner is often associated with expensive equipment, extensive training and access to relatively developed telecommunication infrastructure. In an attempt to overcome these obstacles, a group of scientists have published a new paper describing a device dubbed the universal Mobile Electrochemical Detector (uMED). The machine itself can currently test for Malaria — with hopes to one day diagnose diseases such as Ebola, HIV, E. Coli, hepatitis, influenza, West Nile virus and Dengue fever — by analyzing drops blood and water for chemicals or disease. Once the uMED is linked up to a cell phone, it can then upload the information to the cloud for instant analysis – all for just $25 a unit.


The inexpensive design could make the rising trend of remote diagnostics an everyday reality across the globe. The team developed a custom electrochemical sensor compatible with an Atmel-based Arduino in order to power the inner workings, while a simple audio cable connects the medical gadget to a cell phone for uploading. Subsequently, uMED can easily adapt to geographic needs and updated with minimal training. Many of the medical tests are conducted with an electrode, testing and receiving various data from drops of liquid on test strips. The devices also features a vibration motor to mix samples, whenever the need arises.

“Integration with the cloud is important especially if the required expertise is not present on site to interpret the tests,” Head study scientist Alex Nemiroski tells Popular Mechanics. Once the information is collected by the uMED, it is uploaded to a cloud database just by making a phone call. This device does not require a strong data connection or a smartphone, making it viable almost anywhere on the globe.


Nemiroski breaks down this choice to not create a smartphone app to Popular Mechanics, “We decided instead to focus on a universal solution that is compatible with all generation of cellular technology.”

Although the use of mobile devices continues to rise throughout most of the world, there are still billions of people still required to use older, often times obsolete, technologies for means of communication. “People in many of these regions routinely use their low-end mobile phones for banking, news, education, and healthcare,” he concluded. “Even in many of the poorest rural areas in the world that lack resources to pave roads, run power lines, or install pipes, people still have access to mobile phones.” Therefore incorporating medical testing into this handheld technology could only help improve the general well-being of the world population.

A hitchhiker you may want to pick up…

This summer, hitchBOT is planning on hitchhiking across Canada without a chaperone. The robot designed by David Smith and Frauke Zeller is on a 3,700-mile quest to successfully catch free rides from Halifax to Victoria.


According to Popular Mechanics, the friendly hitchBOT comes outfitted with a rubber hitchhiking hand, speech recognition software, and even its own Wi-Fi network. Those who pick of the traveling gadget can challenge it to trivia, send the robot tweets, and even recharge his batteries.

Powered by a simple tablet and Arduino, hitchBOT has a bucket for a torso, blue swimming-pool noodles for arms and legs and a smiling LED panel for a face, protected by a cake saver. It wears yellow gloves on its hands and rubber boots on its feet. Together, all the parts cost about $1,000; however, the experience of picking up this friendly robot… priceless.

In an interview with Canadian outlet, GlobalNews, the robot’s “family” says that hitchBot’s welcoming exterior was created from a bucket and some pool noodles. But don’t let his low-tech shell fool you, hitchBOT has some serious tech inside. He has Wikipedia’s API built-in to his interface to allow for the processing of world knowledge, as well as boasts 3G and wireless capabilities for his social media needs.

HitchBot has already become quite the social media phenomenon in Canada gaining nearly 19,000 Twitter followers and over 6,500 on Instragram. This social presence is exactly what the creators were aiming for as David Smith notes, “This is an emergent piece of cultural theatre and artwork that’s meant to reframe our thinking about how we adopt and integrate technologies into our social and culture life.”

To follow along with hitchBOT’s journey, you can check its up-to-date location on the project’s official page.