Ask MAKE: Liquid level sensor for brewing system?

Hi, I am building an automated brewing system for home brew beer. It will be controlled via an Arduino and network interface. I am using 15 gallon stainless steel kegs as brewing vessels. What is the best method or type of liquid level sensor to use to accurately detect liquid levels in the kegs? The liquid won’t be water alone, and all three vessels will be heated. I was thinking of using an external sight glass + a pressure sensor of some kind. Maybe someone in the Make community has a better idea or has done this before?

I have been a Make subscriber for the last two years(since I found out about you guys) keep up the great work!

Thanks Brett! So, you want to measure the level of a liquid in a tank. These are some of the ways that I can think of to do this:

• Capacitive: Measure difference in dielectric constant between air and water
• Differential pressure measurement: Measure pressure at bottom of liquid
• Optical: Use an array of light sensors to sense where liquid is/isn’t
• Float: Put a float on a stick, then measure the displacement of the stick
• Weight: Weigh the liquid, and calculate volume based on density
• Conductivity: Measure liquid conductivity at a few discrete points

Out of these options, what would be best? I think for your project, the best way to go is probably to use a differential pressure sensor, like you suggested. It seems like it would be the most reliable and least invasive method. Also, it just so happens that the folks who wrote the Practical Arduino book have a Water Tank Depth Sensor project that might be a good starting point.

If you only want an approximation of the amount of liquid in a tank, a simpler way to go would be to test for conductivity at a few points along the side of the tank. You wouldn’t be able to sense the exact amount of liquid present, but it would be a fine way to check if the tank is half-full or not. The folks at electronics labs built a single-point Water level detector using a PIC microcontroller, which could be expanded to measure multiple points

Capacitive sensors might work, but might be hard to set up in a metal tank. Optical sensors work the same way as the conductivity sensors, and would be more expensive, so they probably aren’t worth the trouble. A float could potentially work, but could get gummed up by hops or dead yeast, so it might be unreliable. The weight sensor could also work, but I think it might be tricky to keep it calibrated.

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Samsung Galaxy S IV has built-in temperature and humidity sensors

I'm not going to lie: I love my iPhone 5. After watching the Samsung Galaxy S IV press conference, several key features of the new Galaxy S IV caught my eye. The main one that I'm interested in is the integrated temperature and humidity sensors. The new device features nine different sensors for sensing the environment around you.

The first six in the list seen above are commonly available in most devices on the market. It's the new sensors that they have added into the device that really allow the device to go to the next level. It's absolutely sweet that my phone can figure out the temperature outside as well as how humid it is.

Those sensors turn the Galaxy S IV into a mobile weather station, especially when coupled with the barometer. The new IR Gesture sensor is what powers the cool new Air Gestures feature. For more about Air Gestures, see my colleague's post from earlier this evening.

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Learn details of the nano gas sensor industry of the United States market 2016

The United States Nano Gas Sensor Industry 2016 Market Research Report is a professional and in-depth study on the current state of the Nano Gas Sensor industry.

The report provides a basic overview of the industry including definitions, classifications, applications and industry chain structure. The Nano Gas Sensor market analysis is provided for the United States markets including development trends, competitive landscape analysis, and key regions development status.

Development policies and plans are discussed as well as manufacturing processes and Bill of Materials cost structures are also analyzed. This report also states import/export consumption, supply and demand Figures, cost, price, revenue and gross margins.

The report focuses on United States major leading industry players providing information such as company profiles, product picture and specification, capacity, production, price, cost, revenue and contact information. Upstream raw materials and equipment and downstream demand analysis is also carried out.

The Nano Gas Sensor industry development trends and marketing channels are analyzed. Finally the feasibility of new investment projects are assessed and overall research conclusions offered.

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Barometer: a free app that showcases the iPhone 6 barometer sensor

Looking for a cool new free app to try on your brand new iPhone 6? Then look no further than Peter Breitling’s Barometer—a new easy to use barometer app for the iPhone 6 and iPhone 6 Plus.

Barometer is an extremely simple app with a minimal design. It allows you to easily measure heights, such as when riding an elevator, check altitude, perform measurements, and more.
It’s so cool that I deemed it worthy to create a video showcasing it in action. Have a look at our video demonstration of Barometer after the break.

The iPhone 6’s barometer sensor is extremely sensitive, and could pick up minimal increases in altitude. It wasn’t always 100% accurate when I pitted it against an old-fashioned tape measure to measure its height, but it wasn’t an egregious differences in measurement, either.

If you have the time, I recommend downloading Barometer and playing around with it. I can only imagine how interesting it would be to take it into a sky-scraper and ride the elevator to the top.

You can download Barometer from the App Store free of charge. Remember, you’ll need to have an iPhone 6 or an iPhone 6 Plus to use the app.

What do you think?

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Advanced CO2 Sensor Industry North America Market Research Report 2016

The North America Advanced CO2 Sensor Industry 2016 Market Research Report is a professional and in-depth study on the current state of the Advanced CO2 Sensor industry.

The report provides a basic overview of the industry including definitions, classifications, applications and industry chain structure. The Advanced CO2 Sensor market analysis is provided for the North America markets including development trends, competitive landscape analysis, and key regions development status.

Development policies and plans are discussed as well as manufacturing processes and Bill of Materials cost structures are also analyzed. This report also states import/export consumption, supply and demand Figures, cost, price, revenue and gross margins.

The report focuses on North America major leading industry players providing information such as company profiles, product picture and specification, capacity, production, price, cost, revenue and contact information. Upstream raw materials and equipment and downstream demand analysis is also carried out. The Advanced CO2 Sensor industry development trends and marketing channels are analyzed. Finally the feasibility of new investment projects are assessed and overall research conclusions offered.

With 152 tables and figures the report provides key statistics on the state of the industry and is a valuable source of guidance and direction for companies and individuals interested in the market.

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Sony creates curved photo sensor, promising better images and cheaper lenses

Sony revealed the world’s first curved photo sensor last week, and have today followed it up with a sample image showcasing a new display technology that the company hopes will result in cheaper photo sensors while delivering higher-quality images.

Curved sensors are expected to solve problems that flat sensors have with light falling in front of their focal plane in certain conditions, and can also reduce noise while reducing their manufacturing complexity.

The problem that flat sensors run into is the so-called Petzval field curvature, that occurs when light passes through the edge of the lens falls in front of the sensor’s focal plane. Lens manufacturers combat this issue by designing lenses with minimal field curvature, a costly process that results in heavier lenses as well. Sony’s new sensor is bent into what the company calls a “Petzval surface,” and reinforced with a ceramic backplate. This means that lenses no longer have to compensate for Petzval field curvature, as the sensor will already do it.

This will allow manufacturers to create shorter and lighter lenses, with larger apertures to boot. The reduction in light falloff at the edges of flat CMOS sensors also allows for less noisy photos.

Sony hasn’t yet been able to produce their curved sensors in any high-megapixel variants, which means that we won’t be seeing the technology in commercial applications anytime soon.

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Sensirion develops protective cover for humidity sensors

Sensirion now offers a protective cover for selected humidity sensors of the SHT3x series. The SHT3x protective cover is an optional polyimide foil directly attached to the top surface of the sensor. It covers the SHT3x’s complete sensing area and thus acts as a reliable shield against pollution during SMT assembly of the sensor and subsequent processes, such as conformal coating or potting. The protective cover is designed to withstand multiple reflow soldering cycles. To enable correct sensor operation, it must be removed after assembly.

A flap on the cover extends over the outer dimensions of the sensor package on one side and is designed to allow the cover to be peeled off easily with tweezers. After peeling off, the sensor will operate as specified in the datasheet. All typical conformal coating procedures, such as brushing, spraying or potting, can be used as long as the protective cover is attached. The cover will effectively protect the sensor opening from direct exposure to these coatings and other possible pollutants during the production process.

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