At-Home Portable Urinary Catheter Monitoring System

Author: Keerthana (Rachel) Kurapati


Several studies have shown that more than 40% of the people over 65 years of age suffer with urinary problems. Urinary catheters are commonly used to treat various conditions and usually provide an effective mitigation allowing the underlying condition to be treated. However, they pose common challenges that can lead to major secondary complications. These catheters can suffer from blockages, lack weight change indicators that might suggest an infection, lack drain volume tracking, lack “clean bag notification” mechanism and lack “empty bag notification” mechanism. Though urine catheters are commonly used, there is no solution that addresses some or all the issues mentioned above. This paper discusses a system that uses IoT and mobile app to solve the above problems by providing automated way of notifying the user and helps avoid several complications.


A catheter is a medical device that is inserted into the human body to aid drainage of fluids and administration of medicines. A urinary catheter is a medical device where a thin tube is inserted into the urinary bladder that aids drainage of urine. Drainage of urine is an essential function and can be blocked due to several possible complications related to diabetes, kidney infections, prostrate issues and so on. Urinary catheter is a very effective way of providing short term as well as long term relief to patients that mitigate the drainage problem and allows treatment of the other conditions. Urinary catheters are by far one of the most used medical devices and serve the purpose effectively.  However, they are not without any drawbacks. These catheters can pose several challenges.


Mechanical issues and challenges

Anytime an external device is inserted into the body, there is a chance of infection and issuesWherever there is a tube involved, there are issues like clogging and loose connection that can arise from time to time.

Some of these issues take time to detect, given that the bladder itself is built to buffer the fluids and expand in the event of a blockage. Issues like buildup of debris can gradually clog the tube causing less fluid to flow through the pipe thereby reducing the effectiveness of the device. These issues can not only reduce the effectiveness of the functionality but can also be a cause for serious concerns like infections, bladder expansion, leakage through the site of incision, disconnection of the tube etc.


Measurement challenges

The primary function of the catheter is to drain the urine out of the bladder so that the inflow and the out flow of water/fluid in the system is maintained properly. Such a method usually comes with careful measurement of intake and output of urine. Measuring of intake can be done by consuming water from fixed set of measured containers.

  • Measurement of the amount of fluid drained could be a challenge, especially when several people including care takers and family members frequently help empty the bag during the day.
  • It is also challenging to detect the concentration changes in the fluid that is drained as it requires special testing from the lab.


Maintenance challenges

The human body drains a constant amount of fluid every hour and it is not practical to hold a bag that can accommodate the output of the entire day. A typical bag size can hold the amount of urine that is drained in 2-3 hours and will need to be emptied periodically. Not emptying the bag can cause issues like buildup of pressure in the bladder that can result in further issues like leakage, reverse flow, infections and so on. Maintenance presents the following challenges:

  • Detection of bag full and near bag full conditions present challenges especially when the person is engaged in activities like travel, sleep etc.
  • Detection of concentration/weight changes in the fluid also requires clinical attention and testing which is often easy to miss.
  • Detection of debris in the bag that does not drain is also a challenge. Being informed on the state of the bag will help determine the right time to proactively clean the collection bag.



Problem Encountered


Actual Result


Patient Outcome

Week1 Urine flow is missing or reduced Oftentimes a sign of kidney failure or a urinary tract infection (UTI) No indication of reduced flow
Week2 Bag is not being cleaned/replaced correctly Could lead to development of bacteria and possible UTI No indication - assumes the bag is in a good state
Week3 Fluid isn’t draining at a constant rate Urine is not being produced at a consistent rate - sign of bladder or kidney issues No indication about the changes in the rate of drainage
Week4 Fluid weight changes Might indicate buildup of a new infection No Indication
Week5 No way to see if bag is close to being filled Could lead to potential backflow of urine from the bag (that usually contains more types of bacteria) into the urinary track or bladder No Indication



Current solutions

Current solutions rely on clinical and manual approaches to address these problems and are highly error prone. These result in increased infection rate and complicate issues related to management of these catheters. Hospitals employ a different mechanism to address these issues and use commercial grade heavy weight solutions which are more intrusive, expensive, high maintenance, can only be possible to employ in a hospital kind of a setting and is administered by trained medical professionals.


Many people live with a permanent catheter and carry on with their lives and deal with the issues as they occur. There are no solutions in the market today that help address all these issues for a regular user.



Brief summary of the invention

The invention consists of a smart enclosure for the urine collection bag which monitors the rate of accumulation of fluid in the bag and raises an alarm if it detects any anomalies. The solution consists of several components as shown in figure 1.


Figure 1 shows the architecture of how all the hardware components come together to light up the solution.




The heart of the device is a Raspberry Pi which is Wi-Fi enabled with a weight sensor, toggle button and a display board attached. The entire setup is placed in a enclosure that will allow the collection bag to be placed on the weight sensor. The Raspberry Pi is powered either using batteries or a power cable. A computer program is written that runs on the Raspberry Pi that wakes up every 5 minutes and reads the weight on the sensor. If the weight read is less than or equal to the previous weight reading, then it raises an alarm and notifies the app using modules like PushOverNotification or similar ones. The toggle button can be used to reset the last weight when the bag is emptied so that the counting starts over. The app can also register the weight upon reset and compare it with the previous reset-weights. The increase in the reset-weights could mean more debris being accumulated in the bag that will allow the app to prompt the user to either clean the bag or replace it. The program also learns the maximum weight the bag holds over a period and can raise an alarm if it is reaching near capacity. This will prompt the user to empty the bag before it becomes full. The toggle 3 button can be used as a snooze button so that the user can suppress the alarm and allow the system to continue.



Figure 2

Figure 2 shows how the Raspberry Pi and Weight sensor (load cell) are connected so that the program/app can talk to the sensor and read values from it.



Figure 3


Figure 3 shows the high-level algorithm that generates alerts based on the rate of the urine flow into the bag.



Figure 4


Figure 4 shows the high-level algorithm that records the amount of urine that is produced every hour



Architecture consists of 5 major components.

  1. Raspberry Pi Processor: Raspberry Pi is a small single board computer which is inexpensive and can perform most of the computational activities that a regular computer can do and it also offers similar network and operating system stack and connectivity to various devices.
  2. Weight Sensor: There are several hardware options here, but the primary function of this sensor is to measure the weight of the object that is placed on it and to interface with the operating system allowing it to read the weight that it registers.
  3. Digital Display Board: This is a board that can be connected to the Raspberry Pi using a standard interface that allows programmable access to be able to display letters and characters on it
  4. Mobile phone: This can be any standard mobile phone that provides development interface to be able to develop and run apps that interface with a http/rest endpoint. This is a device where the alerts and notifications are sent to.
  5. Urine Collection Bag: This is the bag in any urinary catheter that collects urine and typically has markings that indicate the volume of the contents collected in the bag.


Toggle button: This is an optional hardware button that can be connected to the Rasiberry Pi mother board that allows the user to set some configurations. For example, the user can toggle the button to not raise any alarms indicating that he/she is emptying the collection bag. This can also be done using the mobile app, but having a hardware button makes the hardware itself independently usable even without the mobile app.

  • The Raspberry Pi can either connect to WiFi and communicate with the mobile app or it can use Bluetooth technology to talk to the mobile app. The simple and most common method is to host a https/rest endpoint on the Raspberry Pi and configure the mobile phone as a valid client to talk to the Raspberry Pi using Wifi and https. There are standard http client libraries that can be used to issue http get/post calls to talk to the Raspberry Pi.
    • The components are enclosed in a single casing where there are provisions for the bag to properly hang on to one of the hangers. The hangers are constructed in a way that the weight of the bag will fall on the weight sensor that sits directly on the base of the casing. The digital display board is latched to the face of the case so that it can indicate different alerts and warnings in a way that the users can read them. The Rasiberry Pi mother boards also come with the ability to emit standard system sounds/beeps which can be used to provide audio cues along with any visual alarms.



Below is a rough outline of how the app would look like. At a high-level it contains settings, snooze button and a place to receive alerts. Settings provide a place where the user can configure the app to connect to the physical device. The user can also update/adjust any thresholds here and customize the app.


Figure 5

Figure 5 shows the app with alerting functionality



Use Cases

The following are the use cases where the solution will help the user.

  • Get notified when urine flow is missing or reduced: As a user, I get notified when the urine flow from bladder into the bag reduces or stops. The phone app keeps getting updates on the data points throughout the day and keeps track of them. It uses these data points to identify when there is reduced or missing weight changes and can notify the user.
  • Register the amount of fluid drained per day: As the user, I can log on to my phone app and look at the amount of urine drained today as well as historically. The phone app keeps getting updates on the data points throughout the day and keeps track of them. It can determine the amount of fluid drained in a day and can track the trend over multiple days/weeks.
  • Identify when to clean or replace the bag: As the user, I can get notification on my phone informing me about potential dirt or debris being deposited in the bag. This will allow me to take a closer look and either clean or replace the bag. The program on the Raspberry Pi will detect the weight after the snooze button and notify the phone app about the same. This reset-weight is considered as the weight of the bag in its empty state. If the current reset-weight as compared to the original reset-weight increases beyond a threshold, it can be inferred that there is debris deposited in the bag which needs attention.
  • Detect weight changes in the fluid: As a user, I get notified of any concentration changes in my urine that might indicate a new infection or changes in my health. The phone app periodically gets updates from the Raspberry Pi about the weight of the bag. The app on the phone uses these data points to identify the net weight gained in 5 minutes and flags any significant deviations/differences between these data points over a range of time.
  • Notify if bag is close to being filled: As a user, I get alerts when the bag is getting close to being filled. This will give me enough time to allow me to find a place to empty the bag. This is especially useful when the user is travelling or sleeping or taking a long walk when it is hard to manually monitor the bag. The phone app registers the max capacity of the bag by using the data points that are sent. Based on this max-capacity it can detect if the bag is getting close to being full and notify the user.



Use of IoT to monitor and alert based on rate of urine flow.
Use of IoT to automate recording the amount of fluid that is generated.
Mechanism to notify the user if the bag needs to be cleaned or replaced.
Warning system to detect potentially detect concentration/weight changes of fluid as well as the bag (due to debris build up).
Warning system to indicate near bag full condition




Urinary catheters have been used to treat patients for many decades and suffer with several common problems which can lead to complications. The state of technology has rapidly changed and we can solve many of these common challenges by building an IoT based monitoring system thereby making the use of urinary catheters much simpler, safe and effective