This is the final phase for the designing of our pill dispenser. We completed the last minor touch-ups required to the set-up of our pill dispenser and finalized the placement of all the different parts onto the main acrylic board.

We assembled our pill dispenser and made markings according to the existing holes (for screws) on the acrylic board. Corresponding holes on the acrylic board were drilled, then we aligned the various 3D printed parts to the markings on the acrylic and held them in place with screws.

We made some tweaks to the assembly of the pill dispenser by changing the directions of the 3 curved tubes. Initially, they were all parallel to each other with the same curvature (downwards, towards the slide). However, the curved tubes leading from the two dispensing cups closest to the collection up have been rotated by ~90 degrees to point sideways instead, away from the dispensing cup. The curved tube leading from the last dispensing cup furthest from the collection cup has also been rotated by ~90 degrees but in the opposite direction, towards the collection cup.

With these changes, pills are still dispensed onto the slide, while increasing the distance for pills to slide down towards the collection cup. For the first two curved tubes, they drop the pill higher up the slide than before, so that the pill travels a longer path down the slide. For the last curved tube, it has been rotated such that the pill travels an “S” shaped path within the curved tube before it drops onto the slide. These tweaks are made so that pills dispensed from each of the dispensing cups will fall smoothly down the slide without any bouncing, ensuring that the pills will block the laser sensor at the end of the slide and drop into the collection cup. 

We designed a screen holder that could serve 3 functions: (i) house the RPi, (ii) allow attachment of fans to cool down the RPi, and (iii) mount the 7” touchscreen.

Initially, we worked with a 3.5” touchscreen connected directly onto the RPi GPIO pins. However, we bought a bigger 7” touchscreen as we realized that the 3.5” touchscreen is still too small for seniors to use it comfortably. The 7” touchscreen is connected to the HDMI port of the RPi with a HDMI cable and the USB port of the RPi with a microUSB cable. Therefore, we needed to design a 3-in-1 screen holder that could house the RPi, the fans required to cool down the RPi and the touchscreen for users to interact with. This screen holder is secured with screws onto the acrylic board as well, towards the front of the pill dispenser for easy access by users.

Initially, duct tape was used to hold the two parts of each dispensing cup support together, as the two parts had to be separately printed. However, the whole structure “sags” after some time, hence pegs (in black) were added with corresponding holes between the dispensing cup supports (in yellow), in addition to the duct tape on the exterior. This strengthens the whole structure, maintaining the angle between the two separate parts of each dispensing support with less significant “sagging” occurring.

We also added a final touch by 3D printing lids for the three dispensing cups. There is a groove in the lid to accommodate the stopper for the pills, a knob for easy removal of the lid, and a slot for labels; users can slot in a glass slide and paper underneath it, where users can write down details of the pills in each dispensing cup.

The Arduino Mega is secured in the centre of the pill dispenser set-up so that all components (laser, laser sensor, load cell, speaker, 3 motors, RPi) can be connected to it while it stays hidden from view.

The speaker is placed towards the back of the pill dispenser. We reused our previous collection cup (before incorporation of the load cell) as housing for the speaker. Upon completion of pill dispensing at each specified time, the speaker plays a reminder for users to collect the pills. The reminder plays on repeat until the load cell detects a drop in weight, indicating that the user has picked up the collection cup. If the collection cup has been returned to its place but there are still pills remaining inside, the speaker will play another reminder to alert the user about the remaining pills that the user has missed out. Only when the collection cup has been emptied of pills and returned to its place, then the speaker will play music, indicating that the user has indeed fully consumed all the dispensed pills.

Last but not least, we printed a final part to secure the curved tubes to the motor supports. Previously, we had been using a make-shift solution of blu-tac, but this did not maintain the fixed angle of the curved tubes, affecting the path of the pill from the dispensing cup to the slide.

Here is an image of our complete assembled pill dispenser!