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Welcome to the 2D-Printer wiki!
This project is a realtime writing machine, which enable user to write information remotely. This design controls the movement of the pen on the x and y axes through two stepping motors and the up and down movement of the pen through a servo motor. This Wiki page details how to recreate the machine.
| component | Description | Quantity | Supplier |
|---|---|---|---|
| NEMA-17 | Stepper motor | 2 | onecall MC02060 |
| SG90 | Micro servo motor | 1 | eBay |
| Stepper motor coupler | Flexible shaft couplings 5mm to 8mm stepper motor coupler aluminium alloy joint connector | 2 | Amazon |
| Screw rod | 200mm 3D printer T8-2 8mm lead threaded screw rod linear rail bar shaft | 2 | Amazon |
| Brass nut | Dia 22mm Brass 8mm 4-Start Flange Nut for CNC 3D Printer Rod Lead Screw | 4 | Amazon |
| M8 hexagon nut | Toolcraft Hexagon Nuts DIN 934 Galvanised Steel 8 M8 | 4 | Rapid 51-3428 |
| Stainless steel solid rod | 250mm*5mm | 2 | |
| Type ①②③④ acrylic board | The corresponding size and quantity can be found in datasheet | 10 |
| component | Description | Quantity | Supplier |
|---|---|---|---|
| L293DNE | Quadruple high current half-H driver | 2 | onecall 1470423 |
| CTB0500/2 | 2 way 14 A low profile interlocking terminal block | 5 | Rapid 21-1540 |
| CTB0500/3 | 3 way 14A low profile interlocking terminal block | 1 | Rapid 21-1545 |
| M20-6102045 | 2.54mm pitch PC/104 40 connectors | 1 | Farnell 1569230 |
| 10ML100MEFC6.3X5 | Electrolytic Capacitor, Miniature, 100 µF, 10 V, ML Series, ± 20%, Radial Leaded, 6.3 mm | 1 | Farnell 8126160 |
| Servo Motor Control | Motor Driver Board Control | Stepper Motor Control | ||||||||||||||||||||||||||||
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This 83mm*75mm double sided PCB is manufactured at University of Glasgow. There has some difficulties in the soldering process. All the files required to recreate this PCB can be found in PCB design folder of this repository.
- In this design, different motor driving threads are triggered by the comparison result of current coordinates and previous coordinates. This method minimizes system latency. But each thread requires 40ms runtime. During this time, the comparison of the coordinates is still in progress, but the motor is not driven. This means that the effective coordinates sampling interval is 40ms. During this interval, the mouse moves too fast or too slow will cause the pattern on the screen to be different from the pattern on the paper.
- In the future improvement, there are two kinds of schemes to consider:
- limit the moving speed of the mouse or increase the driving voltage so that the mouse moving speed can match the stepper motor speed.
- Rewrite the code architecture. By storing the coordinates value to simulate the mouse move path. Then control the motor. This approach has a huge impact on real time and brings higher latency.
This design uses 9V battery power supply, during actual operation, the battery voltage reduces very fast. The voltage drop has a great effect on the operation of the printer. In the subsequent designs, the addition of a voltage regulator module will be considered and the circuit should be improved to help the program dive the motor.
现有控制笔的结构并不没有将书写质量提到最高。十分依赖桌面平整程度。未来需要在悬挂装置上进行改良
未来可以用轴承来稳定screw shaft，来减少shaft 的摆动，使电机的运作更稳定。
机械结构 Current
*现况分析
around 40ms delay, the movement of 鼠标（显示器上图形会和实际绘画的图像有偏差）现在电机运行基于像素比较，实际运行中鼠标运动速度和电机运行速度不匹配，
*未来提升
pcb 无稳压源，电压随运行时间降低，导致电机运行
需要稳压源增加电源电压
控制笔换成更稳定的机械结构
- Wei Zhang - Hardware and software designer
- Honghao Wang - Researcher and film editor
- Huanyu Zhang - GitHub maintainer and material purchaser