Currently, the only way to measure avalanche conditions is to hike up a slope and manually measure angle, snow pack, and weather conditions, such as temperature and relative humidity. In order to keep people out of harm’s way when trying to determine avalanche risk, we designed the Smart Avalanche Rover (SAR). The SAR system minimizes the dangers of avalanche analysis by providing a remote means to evaluate ambient temperature, relative humidity, barometric pressure, altitude, slope angle, and snowpack profile.
We learned an enormous amount during the course of the project. There were several issues that we learned from when we dealt with the programming, electrical circuitry, and mechanical system. One big issue we ran into was conflicting Arduino libraries. The radio modules that we used for communication between the controller and rover were using Timer1, however, the Servo library and motor driver library we were trying to use both also used Timer1. We ended up using simpler motor controllers instead of shield and we outsourced the servo control to a PIC. We learned to make sure that we don’t use any conflicting libraries after that issue.
We also decided to solder all the components down so that nothing could come unplugged. Everything worked perfectly after soldering up the controller, however, things went very wrong when trying to solder the rover components. Sparking occurred and an actual fire broke out on the back of one of the solder boards. After some research, we determined that the excess flux was causing arcing between components, thus causing current loss and sparks. We had to ditch the solder boards and used breadboards in the rover instead. This did not harm our design since there was room in the rover for bigger boards. The lesson to learn from this is make sure you are careful while soldering.
To drive the rover, we used some tracks from the Kyosho Blizzard RC, however, we decided to determine our own placement for the wheels in the track. This led to some difficulty because it was bad to have the tracks too tight but also bad to have them too loose. It was also difficult to get them running at the same speed. We overcame the frictional losses by using a PID loop to keep the motors running at a desired speed. The lesson to learn from this is to expect error when using motors with wheels/tracks and therefore, consider using a PID loop to run the motors at a certain speed instead of a specific power level.
The entire project took about 3 months. A lot more time was spent towards the latter end of the 3 months than at the beginning. I would suggest following a predetermined plan and spreading out time effectively.
From what we can tell, this is a new project that no one has attempted so far. We didn’t find any patents, videos, or posts about any similar system.
We would use thinner plastic for the body to make it lighter. Also, it would be great to make it possible to attach to a backpack for easy transport. This would require a smaller, lighter system and thus, a redesign.
If you are trying to replicate this on your own, expect a lot of work. We had 4 people working on this project for 3 months and it was still time consuming. Also, expect to learn a lot! There are many different way to code the Arduinos and PICs; you will just have to choose your favorite.
Design Summary
To evaluate the likelihood of an avalanche occurring on a given slope the ambient temperature, barometric pressure, relative humidity, angle of slope and the snowpack profile of the snow are typically measured. Avalanches are most likely to occur when the temperature is above freezing, the slope angle is between 30-60 degrees and hard pack snow is resting on a relatively soft under layer. The present state of avalanche analysis technology dictates that rangers, researchers, and backcountry enthusiasts must travel onto suspect slopes to monitor and sample conditions. The Smart Avalanche Rover (SAR) design mitigates the dangers of avalanche analysis by providing a remote means to evaluate ambient temperature, relative humidity, barometric pressure, altitude, slope angle, and snowpack profile.
The SAR system is driven by parallel tracks. The motion of the SAR is controlled by the user via the custom controller module also illustrated. The user controls the motion of the tracks and thereby the rover via the joysticks. The user must simply push the joysticks up to move the SAR forward and down to move it in reverse. To initiate sharp turns, joysticks may be pushed in opposite directions. A feedback control system allows for high performance on steep slopes and variable terrain.
Desired avalanche risk data are displayed on the controller screen upon command. Temperature, relative humidity, barometric pressure and altitude measurements are made by a sensor module built into the controller. Slope angle measurements are handled by the rover and the values are sent to and displayed on the controller screen. The angle reported represents the orientation of the rover relative to horizontal pointed in the direction of travel.
To obtain the snowpack profile, a probe module is actuated and drives a metal rod into the snow. While the rod is being lowered, a real-time pressure vs depth profile is displayed on the user’s screen. Once the probe has been lowered its full length, it returns to its initial position automatically. The depth profile can then be examined to gauge the relative densities associated with the snowpack.
In the event that the SAR is caught in an avalanche and subsequently covered in snow, an automatic emergency system will be initiated and a siren will sound until the rover is uncovered. The emergency system is triggered when incident light is blocked from the surface of the rover. Therefore the system may also indicate if the rover has flipped over. This system helps the user locate the device and may be disabled prior to use at night or if not desired.
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