43 lines
2.8 KiB
Markdown
43 lines
2.8 KiB
Markdown
## Goal
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Build a handheld device that can be used to test the 8 strand ribbon cables that connect the MRFC522 readers to the RPi breakout board.
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## To Do
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- [x] Design & print ribbon cable tester case bottom half 🔼 ➕ 2024-05-15 ✅ 2024-06-07
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- [x] Design & print ribbon cable tester case top half 🔼 ➕ 2024-05-15 ✅ 2024-06-08
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- [x] Design & print ribbon cable tester battery door 🔼 ➕ 2024-06-08 ✅ 2024-06-08
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- [x] Assembly the unit ➕ 2024-06-10 ✅ 2024-06-10
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## Parts List
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| **Part Code** | **Type** | **Value** | **Mfg Code** |
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| ------------- | ------------------ | ----------- | ---------------------------------- |
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| R1 | Resistor | 68 to 75 KΩ | |
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| R2 | Resistor | 1 KΩ | |
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| R3 | Resistor | 1 KΩ | |
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| R4 | Resistor | 1 KΩ | |
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| R5 | Resistor | 10 KΩ | |
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| R6 | Resistor | 100 Ω | The ratio of R6:R7 is 1:3.3 (0.30) |
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| R7 | Resistor | 330 Ω | |
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| C1 | Ceramic Capacitor | 0.01 µF | 104 |
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| C2 | Ceramic Capacitor | 10 µF | 106 |
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| RV1 | Potentiometer | 100 KΩ | 104 |
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| U1 | Integrated Circuit | LM555 | |
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| U2 | Integrated Circuit | CD4017 | |
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| D1 - D8 | 5mm LED | Red | |
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| D9 - D16 | 5mm LED | Green | |
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| D17 | 5mm LED | White | |
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| J1 - J2 | IDC Socket | 8 pin | |
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## Build Notes
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- Overall current draw is 0.03 A so power is ~0.27W
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## References
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- [This is a good tutorial](https://www.nutsvolts.com/magazine/article/led-chaser-sequencer-circuits), but there is no capacitor to pin 5 of the LM555 as in all the other articles, which seems wrong.
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- [LM555 datasheet](https://www.ti.com/lit/ds/symlink/lm555.pdf?ts=1715218052822&ref_url=https%253A%252F%252Fwww.google.com%252F)
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- [4017B datasheet](https://www.ti.com/lit/ds/symlink/cd4017b.pdf?ts=1715285377632&ref_url=https%253A%252F%252Fwww.google.com%252F)
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- The best [LM555 tutorial](https://www.nutsvolts.com/magazine/article/using-the-555-timer-ic-in-special-or-unusual-circuits). It actually works.
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