36 lines
1.4 KiB
Markdown
36 lines
1.4 KiB
Markdown
---
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active: false
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tags:
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- project
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created: 2025-05-30
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completed: 2025-06-21
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---
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## Goal
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Create door latches that use servos with more torque so that the latch will open under side pressure.
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- Must be able to open with side force of up to 30 Pa (kg/m2)
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- Must be able to lock automatically on closing
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- Must support access port to unlock manually from outside of otherwise sealed box
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- Must only use power when unlocking
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- Must be quiet in operation, no more than 20 dB
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- Must be not cost more than $25 per lock
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- Duty cycle of 20 opens/closes per day
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- Must be made from readily available parts (just in time delivery)
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- Can be level, edge or PWM triggered with a 5VDC signal
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- Power can be supplied separately up to 24VDC
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- Must be no more than 100mm x 50mm x 50mm in size
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- Latch throw must be at least 10mm
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## Tasks
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- [x] Order servos ➕ 2025-05-30 ✅ 2025-05-30
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- [x] Order springs ➕ 2025-05-30 ✅ 2025-05-30
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- [x] Create a circuit to test the latch using PWM pins on the RPi ➕ 2025-05-30 ✅ 2025-06-03
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- [x] Test that the servo can open under side pressure ➕ 2025-05-30 ✅ 2025-06-03
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- [-] Create `SoftPwm` class and use it to drive the servo ➕ 2025-06-04 ❌ 2025-06-18
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- [-] Design a housing for the latch that the servo can attach too ➕ 2025-05-30 ❌ 2025-06-18
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## References
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- [MG-90S Micro Servo Datasheet](https://www.electronicoscaldas.com/datasheet/MG90S_Tower-Pro.pdf)
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