Temperature, Altitude, Pressure Display

During a recent trip to Bhutan, [electronut] wished for a device that would show the temperature and altitude at the various places he visited in the Kingdom. Back home after his trip, he built this simple Temperature, Altitude and Pressure Display Device using a few off the shelf parts.

Following a brief search, he zeroed in on the BMP 180 sensor which can measure temperature and pressure, and which is available in a break-out board format from many sources. He calculates altitude based on pressure. The main parts are an Arduino Pro Mini clone, a BMP180 sensor and a Nokia 5110 LCD module. A standard 9V battery supplies juice to the device. A push button interface allows him to read the current parameters when pressed, thus conserving battery life.

Standard libraries allow him to interface the LCD and sensor easily to the Arduino. He wrapped it all up by enclosing the hardware in a custom laser cut acrylic box. The result is bigger than he would like it to be, so maybe the next iteration would use a custom PCB and a LiPo battery to shrink it in size. While at it, we think it would be nice to add a RTC and some sort of logging capability to the device so it can store data for future analysis. The schematic, code and enclosure drawing are available via his Github repository.

PropVario, a Talking Variometer/Altimeter for RC Sailplanes

propvario

Lift. For a sailplane pilot it means the difference between a nice relaxing flight, or searching for an open area to land. Finding lift isn’t always easy though. This is especially true when the sailplane is hundreds of meters above a pilot whose feet are planted firmly on the ground. That’s why [Tharkun] created PropVario. PropVario is a combination variometer and altimeter for Radio Controlled sailplanes. We’ve seen a few variometers in the past, most often for full-scale sailplane or hang glider pilots. Almost every full-scale plane has a variometer as part of its suite of gauges – usually called a rate of climb or vertical speed indicator.

R/C pilots don’t have the luxury of looking at a gauge while flying though. At altitude even large 2 meter gliders can appear to the naked eye as no more than a dot. It would be somewhat embarrassing to lose sight of your glider because you were checking gauges. The solution is actually simple. A varying audio tone indicates the rate of climb of the plane. Higher pitched tones mean the plane is going up. Lower pitched tones mean the plane is descending. This system, coupled with a simple radio transmitter, has been in use by R/C sailplane pilots for years.

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DIY cell phone alti-variometer

AltiVarioFront

[Vlad-Andre] used some of his free time to build an alti-variometer. He does some para-gliding near restricted air space and wanted a backup altitude warning that would help keep him below the mandated altitude. His solution uses the SparkFun Weather Board in conjunction with their BlueSMiRF dongle to measure altitude and transmit it via Bluetooth. From there, he wrote a program to grab the transmitted data with his cell phone and display the information. His application also has the ability to set altitude warnings and log changes over time.

Using this system he is able to get altitude data with 3.5 inch accuracy. Because the capture application is written in Java it should be easy enough to make this work on other cell phone models. The project is clean and works well but we estimate the cost of the parts to be between $250-300, making it out of reach for those who don’t have a specific need for these types of measurements. This is especially true for paragliders who have much less expensive options available to them.
[Thanks Carl-Emil]