Introduction: Bolt - DIY Wireless Charging Night Clock (6 Steps)

Inductive chargings (also known as wireless charging or cordless charging) is a type of wireless power transfer. It uses electromagnetic induction to provide electricity to portable devices. The most common application is the Qi wireless charging standard for smartphones, smartwatches, and tablets. Inductive charging is also used in vehicles, power tools, electric toothbrushes, and medical devices. The portable equipment can be placed near a charging station or inductive pad without needing to be precisely aligned or make electrical contact with a dock or plug.

As part of Open Elective 2020 at the National Institute of Design, India, we had a workshop called "It's time to make it" conducted by our senior and visiting faculty in Product Design Mayur Bhalavi. This workshop focussed on making and sharing the making part in the community. This is an experimental DIY project which I made to explore material interaction of wood and 3d printing to make a night clock with wireless charger. This would be a boon to people who have a habit of scrolling through Instagram and Facebook till they fall asleep. Let's start making!

Disclaimer: This project was more process-oriented rather than product-oriented for a learning experience. The final output gave results but not satisfactory. I will be uploading the second iteration of this model in the future.

Step 1: Materials Required

Wireless charging circuit

  • Qi wireless charger module amazon link
  • Qi wireless charging receiver (It comes with different ports depending on the phone you are using. I used C- Type for oneplus 7) amazon link

Night clock circuit

  • Arduino nano ATmega 328p amazon link
  • DS1307 RTC amazon link
  • 128x32 Oled / TM1637 module for display (OLED/tm1637)
  • 3mm white Led (20)
  • DHT11 temperature-humidity sensor (optional) dht11
  • connecting wires
  • PCB

Body

  • ABS (3d printing material)
  • 25mm MDF (25x15 cm)
  • neodymium magnets (8 pieces)

Tools

  • Araldite
  • soldering iron and wire
  • 3D printer
  • CNC Router
  • Filer
  • Sandpaper
  • veneer
  • Fevicol SH

Step 2: Testing Circuit

You may need to test the wireless charging circuit. I prefer to use breadboard and jumper wires to test all the components before soldering.

  • Connect the module to USB power and connect your mobile phone and place the phone on the coil. Make sure that the receiver module's coil is placed exactly above the main coil. The led will glow and eventually charging would be indicated. Check the video for the demonstration.
  • Connect Arduino and other components as per the schematics. (I use Arduino Uno for testing but you can use nano too).
  • Open the Arduino IDE and download the necessary library files. I have followed this link for interfacing RTC and led 7 segment display.
  • You can use or modify my code as per your preference. check the COM port and board before uploading. I followed this tutorial link and modified the code. I have uploaded the library as well as the code I have used.

Attachments

Step 3: Assembling the PCB

Now its

time to assemble all the components on a single board. Solder the components as compact as possible but make sure they don’t intersect.

  • Use Vernier calipers or scale to measure the distance between the Arduino and the wireless charging module.
  • It is important as we need to make slots in the body to allow the user to charge as well as reprogram Arduino whenever required.
  • Remove excessive pins and extra wires while soldering. Make sure that you don’t burn the components while soldering.

Step 4: Preparing the CAD Model.

Once the dimensions of each component in PCB is measured let’s start with the cad model

  • You can explore your own design by ideating. I prepared a sheet of exploration and selected the best out of them.
  • I used Solidworks to create two parts, the lid, and the base body. The lid is made from MDF and the base body is 3d printed.
  • Give extra 1-2mm tolerance since the automated manufacturing has some errors.
  • Rendering tools like keyshot can give a better visualization of the final product. You can even experiment with other materials. You can refer to my cad files which i have uploaded.

Attachments

Step 5: Manufacturing and Assembly

As this project was an experimental one, I wanted to make parts using a material similar to wood and plastic. I chose CNC milling of MDF and 3d printing to save time. I would recommend going for hand operations to have close tolerance control. The following are the steps which I followed:

  • Take MDF at least 10mm thicker than the part height. My part height was 10mm and I took MDF of 25mm. Cut the MDF so that there is at least 20mm distance on 4 sides for fixing bolts. It is always good to have 2-3 extra parts just in case the MDF breaks.
  • Use screws/bolts to fix the MDF board on the CNC router.
  • Upload the step file and start the router. While selecting cutter use the one most suitable to manufacture your component. I used a 6mm cutter but it is recommended to go for smaller ones. Reduce the speed so that there is less chance of breaking or crack propagation.
  • After the process, use cutter to remove slabs of the part.
  • For reducing height use all cut machine to get close tolerance. Then proceed for sanding machine to remove materials of 2-3mm thickness.
  • For the upper depression, fix the part on benchwise and slowly remove the material using file and sandpaper. stick the sand paper on a wooden block to get flat surface and use it.
  • For the plus cut out, draw the desired shape and use drilling machine to cut out the mataerial.
  • Use paper veneer to cover the flat posrtion. This is done so that the led glows in form of plus sign. apply fevicol SH and apply paper veneer by gently pressing it and holding it till it dries. Use sand paper to give finish to the sides.
  • Use araldite to place the magnets in the slot.

For 3D printing I used white ABS in ultimaker. It is better to orient your STL file in such a way that the outer portion will get the best finish. After printing remove the support material and stick the magnet using araldite.

  • Use Araldite/fevi gel to stick the display in the slot.
  • Solder the diplay connections
  • Solder the extra LED used in side as well as the plus symbol (optional).
  • Solder the 5v and ground from the usb port in wireless charging module to Vin and GND port of arduino. This is done so that once you plug in the usb power, arduino is also activated.

Step 6: Learnings

Since this was an experimental project, it did not come out as expected. There are a few learnings that I would like to keep in mind for my next iteration.

  • Prepare a mental making sheet by listing down all the processes involved in making the product. This would give the processes and their dependencies. Prepare a Gantt chart if possible and adhere to it strictly.
  • Always prefer hand operation for the final model. Rapid prototyping methods are only for mockups that do not give a proper finish.
  • MDF is easy to work one but the material finish of the wood is unmatched. You can achieve the look of wood by applying veneer but that would only be possible if your surfaces are flat.
  • Press fits are less dependable unless you are going for industrial-grade injection molding.
  • Reduce the number of components keeping the assembly easier.
  • For products like these, design as little as possible by following Braun design. Keep an eye for detail and craftsmanship.
  • Keep the process in mind before manufacturing. Search for related products and their materials and study its manufacturing before starting to make your product.