Final Project Week 1: Focus and Prototype

For our final project, my partner and I chose to tackle the issue of toilets being too loud and scaring children, leading to them not flushing after themselves. 

To remedy this, we decided to create a device that would give children time to leave the bathroom stall before the toilet flushed. This device would work by first having the child press a button (rather than the flush handle), which would then trigger an ultrasonic sensor to start sensing if an individual is in the stall, as well as a timer to start timing. If the sensor senses that a child is in the stall, the toilet will not flush. If it senses that there is no child, the toilet will then flush. We also wanted to make sure that the toilet flushes in a  timely manner, so we would also have the toilet automatically flush if two minutes have passed without it flushing. 

In order to delay the time at which the toilet flushed, we also needed to design a device to flush the toilet in the child's place. We originally thought to use a Lego Bricktronics motor device to manually push down the flush handle of the toilet. This device would be activated when the sensor or timer indicates that it's time for the toilet to flush. When activated, the Bricktronics motor would turn a handle attached to it that would in term push down the flush handle for a couple of seconds. The motor would then reverse directions, bringing the flush handle to its original position. This processed is demonstrated in the video below. 

Before creating a more detailed prototype of our device, we paid another visit to the preschool we were working with to get more details on the toilets we would be designing the device for. In addition to taking measurements of the toilets' dimensions and pictures of the toilets, we also talked a bit with the school's director, Becky Geer. During this meeting we leaned that the delay needed for flushing the toilets was only about 10-20 seconds rather than two minutes. 

Toilet in the Preschool:

Closeup of Flush Handle:

Once we had more details on the toilet's dimensions, we then set out to build a more detailed prototype of the flushing device using a Bricktronics motor. The to-scale prototype featured the motor, the pushing attachment, a flush handle, and a box to cover the device to prevent children from touching it and water from getting on it. 

One thing to note is that the pushing attachment for the motor is designed to reach around the lip of the toilet tank cover to properly reach the flush handed. 

Once we had the overall design of the device worked out, we then had to think about the applicability of it, specifically whether or not the motor had enough torque to successfully push down the flush handle. To test this we used a spring scale to measure the force needed to pull down the flush handle on actual toilets. What we found was that the the force needed to push the handles down was more than our current motor could handle. 

We considered changing motors or creating a gear train to remedy this issue, but eventually our instructor, Amy Banzart, suggested we use a device that worked to flush the toilet from inside the tank, rather than by pushing the toilet handle from the outside. Due to time constraints we ended up ordering an automatic flushing device to use its motor rather than creating our own .

Device Used: Santeen Home Office Indoor Sanitary
 Automatic Hands-free Sensor-based Flushing System

The above device actually contained a sensor of its own, but we took it out in order to use our own ultrasonic sensor. 

Next week we will focus on creating a code for the motor, button, and ultrasonic sensor