Category Archives: sensor

Tiny $25 Spectrometer Aims to Identify Materials with Ease

Reflectance spectrometers work on a simple principle: different things reflect different wavelengths in different amounts, and because similar materials do this similarly, the measurements can be used as a kind of fingerprint or signature. By measuring how much of which wavelengths get absorbed or reflected by a thing and comparing to other signatures, it’s possible to identify what that thing is made of. This process depends heavily on how accurately measurements can be made, so the sensors are an important part.

[Kris Winer] aims to make this happen with the Compact, $25 Spectrometer entry for The 2018 Hackaday Prize. The …read more

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Posted in led, led hacks, pcb, reflectance, sensor, spectrometer, The Hackaday Prize | Leave a comment

Open Source Underwater Distributed Sensor Network

One way to design an underwater monitoring device is to take inspiration from nature and emulate an underwater creature. [Michael Barton-Sweeney] is making devices in the shape of, and functioning somewhat like, clams for his open source underwater distributed sensor network.

The clams contain the electronics, sensors, and means of descending and ascending within their shells. A bunch of them are dropped overboard on the surface. Their shells open, allowing the gas within to escape and they sink. As they descend they sample the water. When they reach the bottom, gas fills a bladder and they ascend back to the …read more

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Posted in sensor, The Hackaday Prize, underwater, water quality | Leave a comment

Robot Radar Module

For his Hackaday Prize entry, [Ted Yapo] is building a Robot Radar Module breakout board. His design uses the A111 60 GHz pulsed coherent radar (PCR) sensor from Acconeer AB (New Part alert!) .

The A111 is a low power, high precision sensor ideal for use in object detection or gesture sensing applications. The BGA package is tiny – 5.5 mm x 5.2 mm, but it does not appear very difficult for a hacker to assemble. The sensor includes an integrated baseband, RF front-end and Antenna in Package so you don’t have to mess with RF layout headaches. Acconeer claims …read more

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Posted in lidar, radar, robot, sensor, The Hackaday Prize | Leave a comment

Color-Coded Key Opens Doors, Opportunities

Of all the ways to open up a lock, there are some tried and true methods. Keys, combinations, RFIDs, picks, and explosives have all had their time and place, but now someone else wants to try something new. [Erik] has come up with a lock that opens when it is shown a pattern of colors.

The lock in question uses a set of color coded cards as the “keys”. When the cards are inserted in the lock, a TCS230 color sensor interprets the pattern on the cards and sends the information over to an Arduino Uno. From there, the Arduino …read more

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Posted in key, lock, security, security hacks, sensor | Leave a comment

An Indoor Garden? That’s Arduino-licious

Gardening is a rewarding endeavour, and easily automated for the maker with a green thumb. With simplicity at its focus,  Hackaday.io user [MEGA DAS] has whipped up a automated planter to provide the things plants crave: water, air, and light.

[MEGA DAS] is using a TE215 moisture sensor to keep an eye on how thirsty the plant may be, a DHT11 temperature and humidity sensor to check the airflow around the plant, and a BH1750FVI light sensor for its obvious purpose. To deliver on these needs, a 12V DC water pump and a small reservoir will keep things right as …read more

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Posted in home hacks, humidity, Indoor, light, moisture, plant, sensor, temperature | Leave a comment

DIY Capacitive Rotational Encoder on the Cheap with FR4

Rotary encoders are critical to many applications, even at the hobbyist level. While considering his own rotary encoding needs for upcoming projects, it occurred to [Jan Mrázek] to try making his own DIY capacitive rotary encoder. If successful, such an encoder could be cheap and very fast; it could also in part be made directly on a PCB.

The encoder design [Jan] settled on was to make a simple adjustable plate capacitor using PCB elements with transparent tape as the dielectric material. This was used as the timing element for a 555 timer in astable mode. A 555 in this …read more

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Posted in high speed, misc hacks, pcb, rotary encoder, sensor | Leave a comment

“Hey! Don’t Lock the Door, I’m in Here!”

Those that work in front of a computer for a living spend most of the time making very little sound. Unless you’re a member of the clicky mechanical keyboard club, your working time is a low-observables time during which people can forget about you. You can make sure you’re not overlooked with this smartphone hotspot presence detector.

[Emilio Ficara]’s quiet work habits resulted in his housemates locking him in sometimes, to his inconvenience. PIR or microwave occupancy sensors might have worked to fix the problem, except that a few flexing fingers aren’t always enough to trigger them. Luckily, [Emilio] is …read more

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Posted in home hacks, hotspot, occupancy, presence, sensor, ssid, wifi | Leave a comment

Garage Distance Sensor Kicks Tennis Ball To Curb

Those with small garages might be familiar with the method of hanging a tennis ball from a ceiling to make sure they don’t hit the back wall with their car. If the car isn’t in the garage, though, the tennis ball dangling from a string tends to get in the way. To alleviate this problem, [asaucet] created a distance sensor that can tell him when his car is the perfect distance from the garage wall.

At the heart of the distance sensor is an HC-SR04 ultrasonic rangefinder and a PIC16F88 microcontroller. [asaucet] uses a set of four LEDs to alert …read more

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Posted in home hacks, microcontroller, pic, PIC16F88, range, sensor, ultrasonic | Leave a comment

Improving the Accuracy of Gas Sensors

If you need a sensor to detect gasses of some sort, you’ll probably be looking at the MQ series of gas sensors. These small metal cylinders contain a heater and some electrochemical sensor. Wire the heater up to a voltage, and connect one end of the resistor to an ADC, and you have a sensor for alcohol vapors, hydrogen sulfide, carbon monoxide, or ozone, depending on which model of sensor you’ve picked up.

These are simple analog devices, and as you would expect they’re sensitive to both temperature and humidity. [Davide Gironi] wanted a more accurate gas sensor, so he’s …read more

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Posted in R, sensor | Leave a comment

Hacking Touch Screens to Count Pulses

Heart rate sensors available for DIY use employ photoplethysmography which illuminates the skin and measures changes in light absorption. These sensors are cheap, however, the circuitry required to interface them to other devices is not. [Petteri Hyvärinen] is successfully investigating the use of capacitive touchscreens for heart rate sensing among other applications.

The capacitive sensor layer on modern-day devices has a grid of elements to detect touch. Typically there is an interfacing IC that translates the detected touches into filtered digital numbers that can be used by higher level applications. [optisimon] first figured out a way to obtain the raw …read more

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Posted in misc hacks, monitor, multitouch hacks, screen, sensor | Leave a comment