Simon

From CMEE4K
Jump to navigation Jump to search

Linux Command - Rescue and boot up

Lorex 4K Camera

Future

Ardunio

Step Motor

A4988 Step Motor Driver
Microstep settings

Stepper motors typically have a step size of 1.8° or 200 steps per revolution, this refers to full steps. A microstepping driver such as the A4988 allows higher resolutions by allowing intermediate step locations. This is achieved by energizing the coils with intermediate current levels.
For instance, driving a motor in quarter-step mode will give the 200-step-per-revolution motor 800 microsteps per revolution by using four different current levels. The resolution (step size) selector pins (MS1, MS2, and MS3) allow you to select one of the five step resolutions according to the table below.

Microstep resolution Setting
MS1 MS2 MS3 Microstep resolution
Low Low Low Full step
High Low Low 1/2 step
Low High Low 1/4 step
High High Low 1/8 step
High High Hgih 1/16 step

All three inputs have internal 100 kΩ pull-down resistors, so leaving the three microstep selection pins disconnected results in full-step mode.

Differences between the A4988 and DRV8825

The DRV8825 is quite similar to the A4988 but there are some key differences:

  • The DRV8825 offers 1/32 microstepping, whereas the A4988 only goes down to 1/16-step. Higher microstepping results in smoother, quieter operation but is not always needed.
  • The current limit potentiometer is at a different location
  • The relation between the reference voltage and the current limit is different.
  • The DRV8825 requires a minimum STEP pulse duration of 1.9µs; the A4988 requires 1µs minimum.
  • The DRV8825 can be used with a higher voltage motor power supply (45 V vs 35 V). This means it is less susceptible to damage from LC voltage spikes.
  • The DRV8825 can deliver slightly more current than the A4988 without any additional cooling.

Note that the pinout of the DRV8825 is exactly the same as for the A4988, so it can be used as a drop-in replacement! Both can work with 3.3 and 5v.

Cytron LCD Keyboard

Cricut Maker

Sikuli

3D Printer and CNC

Personal interest

Education

Chinese

Keep Idea

  • Create an universal assemble and disassemble instruction for everything
    • Every product must provide disassemble instruction.

Misc

Warning: Kickstart project


Sharing my journey

2019-Jul-17 Status

I would like to share some interesting things when I try to start this non-profit STEM club (CMEE4K).

  • After I announced to look for volunteers, two PhD joined: one Math and one Physics.

We are still looking for a space (room) for meeting.

  • Some churches and their community center rejected us because it is not church related activity.
  • City's community center rejected us because it is conflict with their STEM program.
  • After submitted 'Community Use of School' form to school board for a month, no respond.
  • Currently, we still talking to a library and a culture center.

Digital Divide

We have talking to an Immigration Services and a Youth Centre, here are their situation.

  • Their young (or clients) are from low incoming family.
  • Their family cannot effort ~$110 material fee.
  • They don't have a computer, and possibly no home internet access.
  • We were talking about fundraising. However, CMEE4K has no history and track record.

My observation

  • The IB school STEM club has 10K+ equipment, and their parents can pay $200-$300 club fee without problem.
  • Toronto GTA has many commerce STEM clubs (companies). The parents pay $35-$45 per session.
  • Most of them assume that the students have his/her own laptop. It is a norm for them.
  • Schools selected the high mark students into their STEM club (for Robotic competition).
  • Government funded NGO have STEM program but hard to find them, and have limited spots.
  • CMEE4K is Opened for everyone. If we mixing the paid and the fundraise-support students, will there a social conflict?

I recognized that STEM education is costly. The Digital Divide is difficult for the kids from low income family to catch-up with the rest. Then, they cannot escape from the loop.


李永乐老师 如何才能摆脱贫穷?穷人和富人有什么差别?【2019诺贝尔经济学奖解读】2019-Oct-28

YouTube: 如何才能摆脱贫穷?穷人和富人有什么差别?
2019年诺贝尔经济学奖 如何才能摆脱贫穷.png

  • Ratio: when increase parent education, children will increase education time.
  • Learning disability: Translate the text book from English to their language.
  • Risk / threshold: There is the minimum living cost (threshold) for them to escape / accelerate.
  • Their financial concept: How they use their (low) income.

I like to share the vision of 任正非

任正非的教育情结

  • 把教育做好,国家才有未来
  • 社会重视基础教育,让教师成为最伟大的职业,成为优秀青年的向往。
  • 这个时代对一个国家来说,重心是要发展教育,而且主要是基础教育,特别是农村的基础教育。没有良好的基础教育,就难有有作为的基础研究。
  • 振兴教育不在房子,在于老师。
  • 物质不是最主要的,人才是最主要的,人类灵魂的工程师应该得到尊重,这个国家才有希望。
  • 任正非说:我认为,社会就是应该有口号“用最优秀的人去培养更优秀的人”,“我们再穷也不能穷老师”。
其他

任正非:为什么华为生死攸关的时刻,我反而要谈教育?
如果不重视教育,实际上我们会重返贫穷的。因为这个社会最终要走向人工智能的,因为你可以参观一下我们的生产线,20秒钟一部手机从无到有,基本上没有什么人。
未来我们几百条上千条的生产线完全是自动化的,所以我们的人的文化素质不够,至少你没受过大专或者大学以上的教育,你的英文也不好,计算机也不好,做工人的机会都不存在。
从我们公司的缩影就要看到国家,放大来看国家,国家也要走向这一步,否则国家是没有竞争力的。
不得不说科技和人工智能是未来社会进步发展的必然趋势,一个国家如果想要强大,必须发展科技教育。
因为他们相信只有将科技的“种子”埋在每一个孩子的基础教育中,未来才能生出根来。
而唯有科技人才,才是一个国家最锐利的武器,最坚固的堡垒。
在此前刚结束的国际人工智能与教育大会上就已经明确给出了答案:“人工智能是引领新一轮科技革命和产业变革的重要驱动力”,“培养大批具有创新能力和合作精神的人工智能高端人才,是教育的重要使命”。
而早在,2017年7月,国务院就印发了《新一代人工智能发展规划》,计划在中小学阶段设置人工智能相关课程,逐步推广编程教育。
总之,未来国家科技的发展,一定离不开科技人才的培养,以及当下科技人才的储备。
更有甚者认为中国教育出来的学生,创新能力普遍比西方差。为什么西方的人才普遍具有很强的创新能力?
大家可以看下国外政策环境时间轴。
Diff country computer eduction.jpeg
4-1558958476.jpeg

My record