Power Cleaner - Focus on Your Workout, It Will Focus on Cleaning

My device is the “Power Cleaner” and it sprays disinfectant on dumbbells at the gym by letting ultrasonic sensors and servo motors do the mechanical work so that gym-goers can focus on their workout, especially during COVID. The Power Cleaner works by having two Parallax ping ultrasonic distance sensors as inputs which will detect when the dumbbell is placed back on the rack. It will accomplish this by having each sensor placed on opposite ends of the dumbbell so when the sensors detect a change in distance to less than 8 cm they will send a signal to the output. The output consists of two servo motors, one positional and one continuous, attached to a small spray bottle with a small piece of rope connecting the two servo horns over the handle of the spray bottle. As the servo motors get the signal, they will rotate backward causing the rope to tense up and pull back the handle of the spray bottle leading to disinfectant spray being sprayed onto the dumbbell handle.

The following is a list of supplies needed with the Vendor and any part number that came with the item.

Ultrasonic Distance Sensor, Amazon - Smraza, HC-SR04

3-wire extension, Digi-Key, 1568-1930-ND

Spray bottle (8 oz), Amazon - SuperMMarK, ASIN: B082GPG1HG

ABS filament for 3D prints

Arduino Uno, Digi-Key, 1050-1024-ND

Breadboard, Newark, 79X3922

Micro servo positional, DFRobot, SER0006

Micro servo continuous, DFRobot, SER-0043

Wire Kit, Amazon: Austor, ASIN ‏ : ‎ B07PQKNQ22

4 AA Battery Holder, Jameco, 216187

AA batteries, McMasterr Carr, 71455K58

USB Cable A/B, Monoprice, 39918

Duct Tape

Construct the circuit based on the circuit diagram attached

Download the stand in the attached CAD file and open it in a CAD software program such as Fusion360 to the dimensions given in the image and 3D print two of these using the stronger ABS filament

Once the two stands are 3D printed, attach the ultrasonic distance sensors to the sidewall of the stand, as shown in Figure 3, using tape or a zip tie

Use the dumbbell to set the two stands and sensors at the necessary distance for the head of the dumbbell to be the only thing on the stand as shown in Figure 2

Place the spray bottle next to the dumbbell and the stands as seen in Figure 4, a distance of 15 cm works best usually but you should test it beforehand

Once you figure out the distance the spray bottle should be at, attach the two servo motors to the sides of the spray bottle at a slight angle like in Figure 5 using duct tape

Then using a small piece of rope or a wire, connect the servo horns over the handle of the spray bottle under tension so that the rotation of the servos can pull back the handle with enough force to have spray come out using knots at the horns and tape at the handle

Your final product should look similar to Figure 2 shown above or on the first page

Once the “Power Cleaner” is fully assembled, first take off the dumbbell to prevent any unwanted activations by your circuit. All you have to do is download the code from "codecircuit.ino" attached below to the Arduino board and power the circuit using a 4-AA battery pack or an equivalent voltage battery hooked up to the Arduino Vin and ground connections. You can then place the dumbbell on top of the two 3D printed stands and the ultrasonic distance sensors will automatically detect the dumbbell and wait 3 seconds before rotating backward, giving time to the user to remove their hand. It will then release the spray and wait 10 seconds before returning to its original position. In these 10 seconds, you will need to remove the dumbbell or remove the battery from the Arduino so that the circuit does not run in an infinite loop thus draining the battery.