Author:Anon1701, Translation: Cherry
Have you ever thought about making a computer that fits in the palm of your hand? I have, so I created this small laptop that I call Pi-Micro. This is the third version of Pi-Micro, which has been in the making for nearly a year, and it is refined enough to share with everyone. Pi-Micro can run a complete Linux operating system. It can browse the web, edit documents, use the terminal, create custom programming scripts, and play games. As far as I know, it is the smallest computer made using Raspberry Pi, and it also has a full keyboard. Made with Raspberry Pi Zero W, it has built-in WiFi and Bluetooth.
Pi-Micro Specifications:
512 MB RAM, 1GHz processor, built-in WiFi and Bluetooth, 3.5″ touchscreen, 1000mAh lithium-ion built-in battery, 16GB internal storage, full QWERTY keyboard, 108mmX19.5mmX70mm
The Journey of Making Pi-Micro
(If you want the good stuff, please skip this part.) This laptop has been refined for over a year, and during this year, I have gone through many different versions of designs and prototypes. The first two versions I designed were quite heavy, and the weight of both rotating axes was not suitable for the screen/mainboard.
a. V1.0 (Black) My first version of Pi-Micro was made on May 6, 2017. It used a 3D printed rotating axis, which was too loose to hold the screen upright. However, I liked the keyboard, but it was very thick and heavy. The edges of the top and bottom of the case were not rounded, and the shell was very cheap.
b. V2.0 (Blue) My second version of Pi-Micro was made around October 2017. I tried to fix this problem using ultra-small brass rotating axes, but they were still too loose. In this version, I made all the edges rounded to make it look nicer, and I created an interface for the Raspberry Pi in a 3D modeling program instead of soldering iron interfaces. A unique feature of this version was that the connection between the rotating axis and the keyboard could be easily detached. However, I ultimately didn’t like its appearance because it didn’t look like a laptop.
Project Disclaimer
The best projects are never easy. I spent over a year on this handheld computer, going through several versions and modifications to achieve the current finished product. This project involved many difficult soldering/desoldering tasks and a basic understanding of Linux and Raspberry Pi. I am not responsible for any injuries or other issues that may occur. Always wear appropriate protective gear, do not connect red and black wires, and absolutely do not puncture the battery. Be careful!
3D Printed Shell
Model files can be downloaded from the project repository.http://maker.quwj.com/project/44Print parameters are as follows: filament: ESUN PLA + thickness: 0.2MM shell: 3 infill: 80%
Component List
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Raspberry Pi Zero W × 1
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3.5-inch touchscreen display × 1
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3D printer × 1
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Power bank × 1
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Mini Bluetooth keyboard × 1
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Micro SD card × 1
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USB socket × 1
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Sewing needles × 2
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Various wires
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Screws
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Glue
Disassembling the Power Bank
The purpose of disassembly is to obtain a thin battery/charger combination, power switch, 5v output. Step 1, remove screws from the case, then take out internal components from the aluminum shell. Step 2, cut the wire from the solar panel to the controller board. Step 3, disconnect the battery, then reconnect it with two 3-inch long wires between the battery and the controller board. Step 4, disassemble the USB port and solder the wires to the positive and negative output of the controller board.
Preparing the Screen Component
Important Note: This step is based on the Waveshare 3.5″ display. If you use a different display, please change the soldering wire pins to match your display specifications. For more details, refer to the link at the bottom of the article. 1. Remove the shell from the touchscreen. Personally, the easiest way is to use flush cutters to cut it off, then use a soldering iron to remove the lower half of the pins from the circuit board individually. 2. Solder wires to pins 1, 2, 6, 11, 18, 19, 21, 22, 23, 24, and 26. 3. Label all wires for clarity, as shown in the picture. 4. Double-check the labels. 5. Drill holes in the 3D printed display parts for assembly. 6. Check the labels again. Trust me, it will save you a lot of frustration. 7. Place the screen inside the parts and assemble it together.
Soldering USB Socket to Raspberry Pi
I installed the USB interface at the bottom right of the computer. 1. First, use pliers to cut off the small tags on both sides of the USB socket (not any of the four pins), as they are not used to secure the USB. 2. Bend the four pins down at a 90-degree angle to extend out the back without extending out the bottom. 3. Solder wires to each pin, making sure they are long enough to extend from one side of the case to the other. Use heat shrink tubing to insulate the port if necessary. Tip: Use different colored wires; it helps to distinguish which ones you will connect to the Pi. 4. Using the circuit diagram above, solder the wires to the pads on the Pi.
Soldering the Battery to Raspberry Pi
1. Solder the red wire from the power 5V output to the Pi 5V pin. 2. Solder the black wire from the power GND output to the Pi GND pin.
Soldering the Screen to Raspberry Pi
This step is very tricky, so be careful. 1. Try to keep the wire lengths short. If your wires are too long, they will pile up inside the bottom case, making it difficult to close. Measure the distance each wire needs and cut them accurately, so there is a 2CM gap between the edge of the display and the edge of the bottom case. 2. Connect the labeled wires to the corresponding pins on the Pi. Make sure to confirm each wire.
Installing Software
You need at least an 8GB Micro SD card, but the size you choose will determine the internal storage capacity of the Pi-Micro. This is an important step, as it also helps determine if the screen and battery are connected properly. 1. Format the Micro SD to FAT32. 2. Download the pre-configured system image for the Waveshare display from here. 3. Use Etcher to write the system image onto the Micro SD. 4. Insert the card into the Pi, turn on the battery, and wait for good news. 5. If everything goes smoothly, it means your installation is correct. If there are issues, double-check all solder joints and connections. 6. Pair the Bluetooth keyboard with the Pi. This means we won’t have to access the pairing button on the keyboard later, and it will connect automatically every time we start it.
Reducing the Size of the Keyboard and Soldering it to Raspberry Pi
For the keyboard of Pi-Micro, we will use the mini Bluetooth keyboard from the battery and then solder it to the Pi. 1. Open the keyboard case. I found the easiest way is to bend the keyboard until a gap appears between the top and bottom of the box, then use a flat screwdriver to pry it open. 2. Remove the micro USB charging port. Heat the back of the port to do this, and when the solder melts, it will slide off easily. 3. Remove the battery. 4. Solder two wires to the battery connection ports. 5. Turn it on. (When we connect it to the Pi, make sure it will turn on at the same time.) 6. Solder the wire from the positive terminal of the battery to the 3.3V pin on the Pi. 7. Solder the wire from the negative terminal of the battery to any GND pin on the Pi.
Assembling All Components
Tip: This is the most tedious part, so please be patient, friends. For the rotating axis part, I decided to use needles as the pivot. If there is any resistance during the entire installation process, do not force it. Organizing the items inside the case is much better than forcing them in. 1. Ensure everything fits. Place all components inside the case, put the lid on the bottom part, and make sure it is flush. If not, make adjustments. 2. Use hot glue to secure everything (except the battery, which may explode). This ensures that nothing shifts when you shake the finished computer and that you won’t push it into the computer while trying to use the USB and charging ports. 3. Now that everything is secure, put the lid on the bottom part and fasten it with screws. You may need to pre-drill holes, as the thickness of the screws that can be used varies, so I did not include these holes in the design. 4. Place the display on the bottom part. Make sure it can be mounted on the bottom rotating axis and can rotate. 5. Install the needle. I recommend using the largest diameter needle, as the rotating axis may become stiff, and you may need to push them with the tip of a piece of wood or something else. 6. If necessary, melt the plastic at both ends of the needle to prevent it from sliding out. 7. If needed, solder any gaps around the edges of the bottom and lid with a soldering iron.
DONE! It’s finished! I hope you all like this project!
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