Rain Gauge

Current Progress

Rain Gague

Problem statement

Rain gauges are used everyday by millions of people for countless reasons. From predicting floods to watering grass, their data can be needed across a variety of fields from farming to meteorology. A National organization known as the Community Collaborative Rain, Hail, and Snow Network (CoCoRaHS) consisting of over 20,000 volunteers takes rainfall data from all over the country and sends it to the National Weather Service to help them predict the weather. These gauges have data recorded manually, which can introduce human error into the equation and result in inaccuracies. There is also valuable information such as the rate of rainfall lost with manual rain gauges, which also need to be emptied daily. Even with human error, the manual rain gauge used by CoCoRAHS is the most accurate in the world. To be able to be self-emptying, to be accurate, and to be able to record certain data sets would eliminate many sources of human error, and therefore reduce costs in general to those interested in rainfall and potentially save lives.

Decision Matrix


Tipping bucket rain gauge

This gauge is the standard for automatic rain gauges. It uses a system called the bucket tipper which makes the system not very accurate. However the system can connect to WiFi, is not very expensive, and semi durable.

CoCoRaHs gauge

This is the most accurate manual rain gauge in the world. This rain gauge is very accurate and not very expensive. However this rain gauge is not able to record data, use WiFi, or empty itself. This rain gauge may be very accurate but without an automatic feature it falls short.

Decision Matrix

These are products that have attempted to solve our problems but have fallen short in one way or another. Here we make a decision matrix to see how products stack up against one and another. We use 1 as being the lowest score and 5 as being the best score. We rated the products out of six categories: price, accuracy, durability, measurements taken, is it automatic, and what type of precipitation the gauge can measure.

Presentation and Justification of Solution Design Requirements

After reviewing several other previous products that attempted to solve our solution we have found criteria that we will need to meet in order to make our product better than others currently on the market.

Durability- Able to withstand being outside in harsh rain storms, and can take normal outdoor use.

Size, weight- This will need to be very small so that it does not take up much space, but it will need to be large enough to fit and hold all parts of the rain gauge safely. It will also need to be light enough to be carried by the average person by also heavy enough to remain planted in the ground.

Operating environment- This product will be outside almost always and will need to be able to keep its internal parts dry.

Aesthetics- This gauge will need to be able to not be an eyesore to the rest of the neighborhood. Could provide normal white and gray colors, but also a camouflage variant.

Performance- This gauge will need to be very accurate and will need to be constantly recording data to send to the website.

Product analysis

Concept 1

Two rain gauges side by side hooked up together

Arduino board and Wifi chip

Pro: both accurate and can record data

Cons: heavy, not very stable, parts can be unreliable

Concept 2

Double sided cup

Sparkfun board, scale and photon chip

Pros: Accurate, can empty itself, wifi connectivity, constant reading on website

Cons: More expensive, delicate scale/ parts

Concept 3

Two rain gauges in one

One takes accuracy measurement, the other records data to wifi

Pros: Medium accuracy, not expensive, wifi ability

Cons: Complicated system, funnel could get easily


Why Concept 3 Was Best

Concept three was by far our best idea, because of the many pros and few cons it had. First this was our only idea that one that used only one system and did not connect two systems together. This would end up being very problematic and cause us to have to use more than one ardiuno system which would increase the price and make the system not as cost effective. This system also was the only that could connect to Wifi well and record data in real time. When using a scale you get consistent readings that can be reported every second automatically. If we were to use a regular rain gauge we would end up having to make a new system to record and send data without using a scale, maybe something like a light sensor. This concept also was able to empty and reset itself very easily unlike our other ideas. When we needed to empty our cups there would be a motor to simply turn it, but in the rain gauge we would have to cut a hole in the bottom to release the water and this would not be accurate. Overall concept three was by far the best in ever category.


We have used many applications of STEM in our prototype and throughout the phases of production. We had to have critical scientific knowledge of density of materials in order to even start using our scale. We use density because when you divide a unit of weight by a unit of density, you end up with volume. This can then be divided by the surface area of the collector to achieve a water height. As you can see, math is a very import tool to derive the density equation for the total height of the water. Within our project we used a piece of technology called an Open Scale. It is a modified Arduino chip that can measure a load cell and give us the weight of water. I modified the code so instead of outputting a weight it will output the height. For the rotatory cup we used VEX equipment to create the mount. We used a motor, VEX Cortex, and Encoder to make an open loop system so the cup will rotate 180 degrees. This technology allows us to be able to do our calculations for our gauge to measure the amount of rain. It all came together through Engineering. We combined our formulas, technology, and knowledge of density to complete our prototype.

Market Analysis

In the current market there are many rain gauges currently for sale, but none fit the niche that we are trying to fill. Most rain gauges are either manual or automatic rain gauges. Manual rain gauges are more accurate but can not record data and they have to be monitored after every storm. Automatic rain gauges record data, can run themselves and are efficient, but most are inaccurate due to the bucket tipper that they use. We want to make a rain gauge that will be as accurate as a manual rain gauge but will also be able to record data and monitor itself. Most gauges that try to be both manual and automatic are very expensive and are way out or reach of almost everyone, so we want to make it as cost efficient as possible.


Prototype Composition

This prototype is composed of:

-A Spark fun board (arduino)

-attached to a photon chip (WiFi connection)

-Scale under system( spark fun)

-Motor and encoder combo to spin cups (VEX)

Prototype Background

This first prototype use many different components to function which i have listed on the side of this document. We used a load cell and a sparkfun ardiuno chip to calculate the load on the cell to measure the weight. We then used a photon chip to transfer this data from the ardiuno to the internet website that will hold, store,

Prototype Testing and Collection Plan

Accuracy test

1 Set up CoCoRAHS Gauge on top of scale.

2 Set scale to grams

3 Tare scale

4 Pour water into rain gauge to a set amount

5 Read rain gauge (not scale) and record measurement

6 Now read scale and record the measurement

7 Repeat steps 4-6 with different amounts of water

8 Record data in a table like shown below

Function test

1 Set up prototype rain gauge by plugging in wires to get power to arduino

2 Once prototype is set gather twenty inch of water or more

3 Pour four inches of water into the cup facing up.

4 Record if the motor and encoder setup turns the cup to switch the places of the empty and filled cup.

5 repeat this 3 or more times for best results.

Data Results and Testing Analysis

From our data table you can see that our tests went very well. We were able to get around a 2.5% error when comparing our rain gauge to the most accurate rain gauge in the world. We are very pleased with how our gauge worked and that it proved very accurate.

Untitled document
water table

Documentation of External Evaluation

A gentleman with over 20 years of irrigation knowledge evaluated our prototype and gave us a lot of very good feedback. From him we learned many important things about what our prototype does right and what it does wrong. When judging our prototype he gave us many questions to think about so we can better further our project.

  • How accurate will this be with other types of participation?
  • How will you be able to keep the cost down?
  • How will you be able to communicate with an irrigation system?

However he also gave us many complements about what we did right such as

  • I like how it is more accurate the the current bucket tipper
  • I enjoy how it is very easy to use for an everyday person and being able to also set the website up yourself is very intuitive.
  • I like how it can be used by everyone and they can be connect to WiFi.

Overall this gentleman liked out prototype and thinks is has a place in the market and could be very useful in the irrigation industry.

Second External Evaluation

A Gentleman with several years of prior ardiuno and website advice came and talked to us about our project. He thought we had a very interesting way to using an ardiuno. When judging our prototype he had a few questions for us.

  • How will the ardiuno communicate to the website?
  • Will you be able to accurately measure with an ardiuno
  • How will the ardiuno be powered?

This man also gave us a lot of compliments and feedback. One piece of feedback he gave is to try out a website that he knew. He said it would be more difficult to set up but it is more efficient and overall preforms better. However in the end we decided to not use this website because our original website was all we needed for our project.

  • I like how it can use such minimum parts to complete the task
  • I like how the ardiuno is mounted securely and safely to the board.
  • I enjoy how the board is well put together and it is very neatly set up.

Designer Reflection on the Process

Throughout this project we have had many different ideas and have tried many different ways to make our rain gauge work. We needed a gauge that could take multiple measurements such as the amount of rainfall over time as well as the height of the rainfall. The gauge also needed to be able to empty and reset itself, and be able to send data to a website. We original wanted to use two rain gauges that would work side by side of one on top of another to get two different measurements. We soon found this to be faulty and in need of a new idea so we went with the idea of a scale. The scale would prove to be very accurate and work very well as long as it did not get damaged. We ran the scale though many rigorous tests to prove that it could work and that it would be very accurate. In the end the scale idea worked very good and proved itself.

Looking back on our ideas and what we could have done differently we have realized there are a few things we could have improved upon. We should have tried to use many different types of scales and arduino boards to see which ones worked best and were the most durable. We could have also tried to found a better motor or a new way to to turn the cup other than the vex motor and encoder that turned out to be very inaccurate.

Designers Recommendation

Throughout this class we have gone through many steps and have done a lot of work with this project. We have had a lot of very good things come out of it but there are a few things that we can improve upon.

1. When making the prototype we had many problems with our scale. If the scale is bumped or touched in the front or back instead of on the top or bottom, the scale will then send out wrong readings and is inaccurate. Scales need to be kept safe at all times in order to work properly.

2. We also found that Vex materials and parts do not work very well. When trying to use an encoder and motor to turn the cup 180 degrees it did not. Instead it would turn somewhere about 150 to 200. This was an error due to our parts and materials that we had.

3. Throughout the year we had many road blocks and time constraints to deal with. We could have been a lot more efficient with our time, and completing side assignments as well.

4. In testing we also discovered a problem with the website. The photon chip was very hard to use at first. We learned that school internet does not work with the photon chip and needs to use a hotspot on a phone to work for demonstration. It is dependent on the security type of the network to allow the Photon to work.

5. The material chosen for the double sided cup was 3D printer plastic. This plastic by its self does not hold water. When testing the cup we found that the cup will not hold water and was rendered useless, you will need a water tight material. We later found out that if you cover the 3D printed parts in an acetone it will make it completely waterproof.

Mentored Pathways Thank you

Thank you mentored pathways for finding us a mentor to help us with our project. Our mentors have helped us out with everything from calculations to finding out which load cell we should get. Here are our two mentors and what they have done for us.

Bob- This is Brett's mentor. Bob helped me out a lot every step of the way, and here are a few ways he helped. When looking for a new scale Bob was very helpful and found several scales that we could use. He also was able to help us with new ideas for the rain gauge such as how the cup would turn and how the water would drain. However Bob was most useful when we needed help with our coding. He gave us several ways to test what is wrong and helped us to solve our code issues.