What to use for electronically controlled latching setup

l'm working on making a medication organisation box for the senior population mnore than 65 years old. This box will have trays that will be inside containing the medications, different trays will have different medications and there will be a button that when pressed will release the trays that are to be taken at that time. After taking medications from one tray the person pushes the trays back inside the box where it gets latched. The person is suppose to do this for all the released trays.

The logic of what time it is and what trays have what medications and at what timne they need to be taken is managed by a Arduino and a companion Mobile application.

In order to make the box more compact and less noisy am interested in making the trays to be angled inside the box so that they come out using gravity. This will not require use of any stepper moters, gears and selection mechanism.

want the trays to be latch inside the box and control the release by the press of the button using an Arduino.

And this latch is released after the press of the button for all the trays that should come out (according to the logic) and after the person pushes the tray back inside it latches back on.

have to 3D print this box and don't have any idea on how or what parts should use to make this latch so it can be electronically controlled in this manner.

have to make this as a prototype in fusion 360 first and would need the models for the parts that use as well.

Please HELP what parts can make this latch. want this part to be small and do the job acceptably well.

Hi Abhishek, a latch that releases on a pulse and re-latches by itself when the tray is pushed back is a common cabinet-lock pattern. A few options, from simplest to quietest:

1. Small solenoid with a bevelled bolt (my first choice). Use a 5 V or 12 V push-pull solenoid (the JF-0530B size is about 30 mm long) or a ready-made "electric cabinet/drawer lock". Give the bolt a 45 degree bevel and add a small catch on the tray. When the tray is pushed in, the bevel pushes the bolt back and it springs into the catch, so re-latching needs no power. To release, energize the solenoid for about 100-300 ms. It only draws current during that pulse, and the tray then slides out on your gravity incline.

2. Micro servo (SG90) lifting a spring-loaded pawl. It is cheaper and quieter than a solenoid. Keep a torsion or compression spring on the pawl and a bevel on the tray catch so it still re-latches passively; the servo only lifts the pawl to release.

3. Shape-memory alloy wire (Nitinol) pulling the pawl. It is silent and tiny, but slower (about 1 s) and needs a few hundred mA while pulling.

I would avoid a plain electromagnet that holds the tray while powered: every tray would release on a power cut.

Driving it from the Arduino: never connect a solenoid straight to a pin. Use one logic-level N-MOSFET per latch (for example AO3400 or IRLZ44N) as a low-side switch, with a flyback diode (SS14, or 1N4148 for very small coils) across each solenoid coil and a bulk capacitor (470 uF) on the supply. For many trays a TPIC6B595 power shift register can drive up to 8 latches from 3 pins.

Tip: add a microswitch, or a small magnet in the tray with a hall sensor (A3144) in the box, to detect when each tray is pushed back and latched. Your app can then confirm that the dose was taken.

For Fusion 360, most solenoid and lock sellers publish STEP files, so you can import the solenoid and model only the printed bolt and catch around it. Leave about 0.3-0.5 mm clearance on printed sliding parts.Hi Abhishek, a latch that releases on a pulse and re-latches by itself when the tray is pushed back is a common cabinet-lock pattern. A few options, from simplest to quietest:

1. Small solenoid with a bevelled bolt (my first choice). Use a 5 V or 12 V push-pull solenoid (the JF-0530B size is about 30 mm long) or a ready-made "electric cabinet/drawer lock". Give the bolt a 45 degree bevel and add a small catch on the tray. When the tray is pushed in, the bevel pushes the bolt back and it springs into the catch, so re-latching needs no power. To release, energize the solenoid for about 100-300 ms. It only draws current during that pulse, and the tray then slides out on your gravity incline.

2. Micro servo (SG90) lifting a spring-loaded pawl. It is cheaper and quieter than a solenoid. Keep a torsion or compression spring on the pawl and a bevel on the tray catch so it still re-latches passively; the servo only lifts the pawl to release.

3. Shape-memory alloy wire (Nitinol) pulling the pawl. It is silent and tiny, but slower (about 1 s) and needs a few hundred mA while pulling.

I would avoid a plain electromagnet that holds the tray while powered: every tray would release on a power cut.

Driving it from the Arduino: never connect a solenoid straight to a pin. Use one logic-level N-MOSFET per latch (for example AO3400 or IRLZ44N) as a low-side switch, with a flyback diode (SS14, or 1N4148 for very small coils) across each solenoid coil and a bulk capacitor (470 uF) on the supply. For many trays a TPIC6B595 power shift register can drive up to 8 latches from 3 pins.

Tip: add a microswitch, or a small magnet in the tray with a hall sensor (A3144) in the box, to detect when each tray is pushed back and latched. Your app can then confirm that the dose was taken.

For Fusion 360, most solenoid and lock sellers publish STEP files, so you can import the solenoid and model only the printed bolt and catch around it. Leave about 0.3-0.5 mm clearance on printed sliding parts.