STM32F103CxT6 minimum system board (with CH334P)

PDF_STM32F103CxT6 Minimum System Board (with CH334P).zip

Altium_STM32F103CxT6 Minimum System Board (with CH334P).zip

PADS_STM32F103CxT6 Minimum System Board (with CH334P).zip

BOM_STM32F103CxT6 Minimum System Board (with CH334P).xlsx

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Red Knife.jpg

A simple little design, nothing special, just for fun.

Video link:
Attached, same as the Bilibili video:
https://www.bilibili.com/video/BV1BP2qYZEYL/?spm_id_from=333.337.search-card.all.click&vd_source=6e36cb5877fc1084cf9aefe8f240bd03
Project Introduction:
A very simple PCB design,
focusing on something useless but aesthetically pleasing.
Project Functionality
: Functions include only lithium battery charging/discharging and a touch switch, using a flexible ceramic filament as the blade.
Principle Analysis:
1. The lithium battery charging and discharging circuit
uses the classic IP5306 circuit. You can directly copy the chip datasheet. Some minor modifications were made for the design.
Testing showed that the tactile button doesn't require soldering, and
LED1 is unnecessary after assembly; it's practically invisible after assembly.
2. The tactile switch
is a typical touch switch circuit. The TOUCH switch uses the touchpad. Upon triggering, it outputs a high level, turning on Q2 and supplying power to the positive and negative terminals to light the filament.
The value of C20 can be adjusted according to actual conditions; I personally found 2uF sufficient. Besides touch, proximity also triggers, creating a somewhat entertaining effect (lol).
Note:

To reduce the number of PCB fabrications, two identical circuits are symmetrically designed on the board. Only one side needs to be soldered
. Buy two flexible filaments on the same side without soldering wires. The purchase list is attached. The nominal voltage is 3.7V, but testing showed that 5V works after adjustment. This is
a special version for IP5306 power banks; the regular version may not be compatible. There may be instances where the output power is insufficient, causing automatic shutdown.
The resistance of R24 in the touch circuit needs adjustment based on the actual situation. Adjusting the filament brightness and
ensuring the frame is oversized can be addressed by exporting to a JP manufacturer to save on board making costs. However, I personally feel that JLC ​​boards have a better build quality (perhaps due to familiarity).
If only one side of the touch circuit works after assembly, it's likely due to insufficient soldering; simply add more. Assembly process:



Take one outer shell board, solder components on any side, and connect the wires and battery according to the PCB layout .
Take another frame board and solder the filament according to the actual situation (paying attention to positive and negative).
Align the two soldered boards and solder the three holes.
If the soldering is correct, the filament should light up.
After confirming the filament brightness is correct, take another outer shell board, without soldering any components, and directly solder it to the other side. Embed
the filament into the blade's groove and secure it with hot glue. Secure
the battery and charging cable in the handle's groove, wrap it with tape, and then wrap the handle with paracord (refer to a paracord wrapping tutorial).
This link (https://www.bilibili.com/video/BV1kM4m1Q7U1/?spm_id_from=333.337.search-card.all.click&vd_source=6e36cb5877fc1084cf9aefe8f240bd03
) demonstrates how to make a matching Red Knife charging cable using a 2-pin USB-C cable.

Demonstration video.mp4

Other component purchase recommendations.xlsx

PDF_Red Knife.jpg.zip

Altium_RedKnife.jpg.zip

PADS_RedKnife.jpg.zip

BOM_RedKnife.jpg.xlsx

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Dactyl Manuform Flying Cable Reel Board - V2.1

Dactyl Manuform Ergodone Keyboard with Flying Cable Reel Board for Redox STM32 VAIL

Dactyl_Manuform_Flying Wire Switch Board - V2.0
is an optimized version based on anyiyao 1.0:

It fixes a bug where vias leak solder to the back. It uses pads instead of vias
to fix a bug where row and column vias are too close together, easily causing solder bridging. It optimizes the arrangement of row and column pads, reduces the number of pads, and changes the pad shape to square.

Dactyl_Manuform_Flying Wire Switch Board - V2.1 (not tested with prototypes)

merges the middle two column pads
and changes the diode cathode connection to the left pad of the switch seat.

Note that

the diode is an SOD123 package, model 1N4148.
To avoid conflict between the keycap of the bottom key in the middle finger row and the housing, the switch board hole for the top key in the thumb area has been reduced. The switch board for this hole needs to be cut: cut along the white indicator line on the switch board (a file or sandpaper is recommended for polishing). Note that the placement direction of the shaft plate at this hole position is different from others. The cut side needs to be close to the inner wall of the thumb area of ​​the shell, otherwise it will not fit.
It is recommended to make a 1.2mm thick sample board
and V-cut panel (no process edge, 6 rows and 6 columns). The sample price for 5 panel boards (180 single shaft boards) is estimated at 41.53 (excluding postage). Since the original version was drawn using the standard version of LCEDA and the shaft seat components in LCSC no longer have data, SMT placement cannot be used. The price for placing SMT on 5 panel boards is more than 250 yuan (excluding component price, only engineering fee), which is not cost-effective, so the shaft seat will not be redrawn.

Dactyl-APM
has optimized the shell interface of the dactyl manuform, drawn the bracket of APM32F103, and adapted the code simply. Currently, only the 4x6v6 layout model has been verified.
The specific bill of materials is also available in the project
: https://github.com/Byvm815/Dactyl-APM