System Integration
1. Week Assignments
Design and document the system integration for your final project.
2. Prior Knowledge
Oh my… this is definitely a first for me! It feels like packing for some outlandish expedition and designing all it at the same time…
3. Work!
I composed all the components of my final project into a 3D model using OpenSCAD. Before I did that, I checked all PCB board sizes to be multiples of 5mm to make it easier to fit them onto a frame and into the exterior.
3.1. TODO Diagrams?
3.2. Bill of Materials
Below is a list of components to build this clock.
| Amount | Description | Price | Sum | Function |
|---|---|---|---|---|
| 1 | SEEED STUDIO XIAO | 5.75 | 5.75 | Main / RP2350 |
| 1 | DCF77 | 2.69 | 2.69 | Main / Radio Clock Receiver |
| 1 | DFPLAYER - A MINI MP3 PLAYER | 5.01 | 5.01 | Main / Audio source |
| 1 | 8Gb TF (Mini SD) | 12.40 | 12.40 | Main / Audio storage |
| 1 | Speaker | 0.00 | Main / Audio output | |
| 1 | RES 0 OHM JUMPER 1/4W 1206 | 0.10 | 0.10 | Main / Electrical |
| 1 | RES 1K OHM 1% 1/4W 1206 | 0.10 | 0.10 | Main / Electrical |
| 1 | Makerfocus 3.7V 3000mAh Lithium | 15.00 | 15.00 | Main / Battery |
| 30 | ADDRESS LED SERIAL RGB | 0.25 | 7.50 | Display / Light |
| 4 | CAP CER 1UF 50V X7R 1206 | 0.25 | 1.00 | Display / Electrical |
| 1 | KY-040 Rotary Encoder | 2.44 | 2.44 | Docking / Time selection |
| 1 | CONN SPRING MOD MALE 6POS SMD | 1.95 | 1.95 | Docking / Connector dock |
| 1 | CONN SPRING MOD FEMALE 6POS SMD | 1.92 | 1.92 | Docking / Connector clock |
| 4 | Magnets | 0.00 | Docking / Placement | |
| 1 | USB-C PD Trigger Board | 1.67 | 1.67 | Docking / Power |
| 1 | Wood?? | 0.00 | Housing and dock | |
| 1 | Clear acrylic?? | 0.00 | Housing | |
| Total ex. VAT | €57.53 |
3.3. PCBs
I exported all PCBs to STL models and imported them into OpenSCAD.
The above are connected as follows.
Note the holes on the top and bottom edges. They're be used to mount them on a frame.
The main board goes on the back of the display, so the holes in this board align with the holes in the display.
3.4. Electrical components
Apart from the PCBs there are some more components: a battery, a DCF77 antenna and a speaker. I arrange them as follows.
I created a frame (to be 3D printed) to mount the components on.
Note that the speaker is not attached to the frame. It will vibrate and should be attached to the housing.
3.5. Housing
For the outside, I decided on a basic box with rounded sides. The clock will be in the center with transparent acrylic on the outsides, allowing one to see the internals. I am planning on CNC milling these "rings" and providing slits in the edges to lock in the components frame and acrylic windows.
3.5.1. TODO Stacking and locking
The position of the slits will depend on the thickness of the wood to be milled because it is not possible to make a horizontal cut.
3.5.2. TODO Connector
3.5.3. TODO Snooze
To detect a snooze action the clock needs two metal plates to do a step response detection of a hand. First I need to figure out if a hand can be detected through the wood. If not, the plates can go on top of the clock and be coated with something to keep them for oxidizing.
Another option is the use a basic vibrating sensor switch like the Adafruit 1766 of 2384. I think is will be a lot easier to work with.
3.5.4. TODO USB access to RF2350
To make updating the software easier, it would be really nice to have easy access to the USB port on the RF2350. Maybe use a Sparkfun 15455 or make my own extension cable?
3.6. Dock
The base docking station will look something like below.
3.6.1. TODO Connector
See also 3.5.2.
3.6.2. TODO Rotary Encoder
A big 3D printed knob on a rotary encoder. I do not yet know how to attach this properly to the dock.
3.7. TODO Other Loose Ends
- Wiring (pretty ribbon wire with pin header / connectors + heat shrink)
- Power adapter (USB-C or some other 5V adapter)
