Cheap and easy-to-use 40-key inline keyboard [ATmega32A]

Why is it cheap?

The relatively low-cost ATmega32A chip is used as the onboard main control;

The simplest 40-key design minimizes key shaft costs;

Using the splicing circuit board mode, the size of each circuit board meets the free requirements;

All use 1U keys, the keycaps are simple and cheap to install, and there is no need to buy satellite switches;

The structure is simple and the casing is compact.

How to use it?

Carefully designed small layout, all keys are within the comfortable operating range of ten fingers, and the little finger does not need to press the keys outward;

The most frequently used Enter key and Backspace key are under the little finger
of the right hand and can be operated without moving; the keys for switching the 1st and 2nd layers and the shift and space keys are under the two thumbs, and the thumb is no longer just used for pressing. space, effectively improving the utilization of the ten fingers;
press the Fn1 key with the left thumb, and under the left hand is a complete numeric keypad and operation symbols, which is very suitable for left-hand numbers and right-hand mouse operation;
press the Fn2 key with the right thumb, under the right hand are up, down, left, and Home, End and other direction keys, the gestures are similar to holding a mouse, natural and comfortable, especially convenient for moving the cursor when coding; for
all punctuation marks, you only need to press the Fn1 key or Fn2 key with your thumb, and press the corresponding key with the fingers of the other hand. The keys are all in the finger comfort zone;
pressing the Fn3 key with the left thumb, pressing the F key with one hand is simple and easy to use, and the right hand Fn3 key, virtual mouse...

Of course, compared with large keyboards, small keyboards must be learned and mastered by oneself. After forming muscle memory, it is convenient and efficient. The key setting is also becoming more and more perfect with continuous use.
When I used a 40-key keyboard as my main keyboard, I initially set up a right-hand numeric keypad. Later I switched to a left-hand numeric keypad. It took me a while to get used to it, but now I think it’s worth it.

The latest version can splice three circuit boards to form a 60-key keyboard, suitable for users who input a lot of numbers.

The soldering of Type C and 32a chips is a bit difficult for beginners. It is recommended to use a heating table and solder paste to complete it, which is much more convenient than a soldering iron. Except for key shafts and individual components, basically everything can be done with a heating table. Those who are inexperienced can search for relevant content at Station B to learn. Be careful not to weld for too long to avoid damaging the components. The heating table shown in the picture above was bought from a treasure store, and I DIYed a PCB heat insulation bracket, which is simple and practical. For details, see: https://oshwhub.com/iqirtryi/heater-holder

The keyboard structure, key setting and production are basically the same as those introduced in another article of mine, for reference during production:

https://oshwhub.com/iqirtryi/pbk40-rgb-keyboard-c

The minimum system of this project refers to the following materials. Thank you to the original author for his contribution:

https://oshwhub.com/Yomen/atmega32a-with-v-usb

The usbasploader provided by the original author is used. For how to burn, please refer to the original author’s B site video:

https://www.bilibili.com/video/BV1xU4y1f7cr

Reference materials, thank you all for your contributions!

https://www.zfrontier.com/app/flow/2wqGYOQPMpOQ  
https://www.bilibili.com/read/cv5275203/  
https://www.zfrontier.com/app/flow/2dq9AoE37KpE  
https://post. smzdm.com/p/aekz8pdm/  
https://www.bilibili.com/read/cv10071032/  
https://docs.qmk.fm/#/zh-cn/  
http://www.keyboard-layout-editor. com/  
https://kbfirmware.com/  
http://builder.swillkb.com/ 

Any corrections or suggestions are welcome.