DIY Bluetooth Headset (BK8000L Chip) 3D Printed

Hi there!

Here i would like to show you how to make your own wireless bluetooth headset. My motivation for doing this project is the fact that there are a lot of bad bluetooth headsets that i bought recently, so by doing my own i can tweak and develop each stuff i would like it to be. Besides, i also have a personal 3D printer which make this project more exciting and even more customizable.

This headset (BK8000L Chip) features are bluetooth 2.1+EDR compliant, A2DP v1.2, AVRCP v1.0 and HFP v1.5 which is not quite amaze me by looking other modules online that supports bluetooth 4.+ such as qualcomm CSR chips. But the end results satisfied me because it just connects quickly, works like a charm, practical, and of course the most important thing, sounds better than i previously bought. Enjoying movies is also possible because the latency of this bluetooth is approx below 100ms. Some test measurement will be attached below

Given the fact that this project is quite difficult for beginners, i suggest you to be patient when doing this because this requires knowledge like 3d printing, pcb making, soldering, and 3D modelling. Let's dive in!

Tools:

1. 3D Printer
2. Laserjet Printer
3. Screwdriver (-)
4. Solder
5. Scissors
6. Iron
7. Multimeter

Materials:

1. BK8000L Chip (From Aliexpress, etc.)
2. Wired Headset/Earphone (Get the best that you can afford)
3. Lipo Battery 260mah (customizable)
4. TP4056
5. Push Button (smd)
6. Toggle Switch (smd)
7. Resistor 110 ohm size 1206 (3x 330 ohm paralleled)
8. Resistor 10k for TP4056 current treshold
9. Photo paper
10. PCB Board (1mm thickness)
11. Soldering tin and flux
12. PLA Filament

1. Install circuit wizard software and follow the instructions
2. set your print to mirror (SMD)
3. Print the PCB layout above (BK8000L Module 3.cwz)
4. Cut your PCB Board according to the size of PCB design
5. Adjust your iron temperature slightly below the max and start ironing the board for approx. 5-8 minutes (note: first, place the photo paper and heat it from sides to full coverage, then apply some pressure while you iron it(with the tip) in vertical, horizontal, and diagonal path. never move or overheat the paper while you iron, the ink will bloated)
6. Soak the PCB in water for 2-3 minutes
7. Rub the paper until the ink seen, also dry it to see if there are some leftover paper
8. Use ferric chloride (FeCl3) solution until the PCB formed.
9. Place your components w/ solder (BK8000L Chip, resistor, female pin header, toggle switch, push button, Lipo Battery)
10. Test for any shorted lines w/ multimeter

This part, you need AutoCAD software for redesign mine (wireless 3.dwg). I also provide you the stl. files (3a and 3b) above. You can tweak the width, compatibiblity of your component, etc. After you ready with your design, 3D Print it

The first picture shows the 3D Printed parts (2 pieces) for top and bottom closure, then the next pic shows the complete soldered battery and components as shown before. Glue both of the 3D Printed pieces and headset cables as shown above. It's necessary so your component and cable wont fall out. The last pic shows the bottom closure with charging port (+ & -). The polarity MUST NOT reversed when you charge with current treshold modified TP4056.

1. Sound test by comparing real mp3 file and recorded result of this bluetooth headset (phone as recorder so result may affected by the phone mic or environment)
2. Latency test by recording the video and bluetooth of transmitter simultaneously with screen recorder and audio recorder (Result: late latency <100ms)
3. Amperage measurement to calculate the battery life:
   • Bluetooth sniffing: 30-50mA
   • Bluetooth playing audio: 55-60mA Equal to 0.222 Watt
   • Bluetooth pause: 25mA
   • Bluetooth idle: feature not available
   • 260mah 3.7v Battery equal to 0.962 Watt Hour
   • Theoretical Battery Life: 0.962/0.222 = 4.33.. hour of music playing at max volume continuously

Yay that's it! hope you like my bluetooth headset project.

• For future development i'd like to improve the quality and battery by using affordable qualcomm chips: CSR86xx
• I also excited about fitbit-alike charger dock for future project for convinience in charging

UPDATE >> Charging dock is now possible!

5/13/19

Just a quick update for the fitbit alike charger that i designed this week. This design turned out really great and make this bluetooth headset charged up all the time. As you can see from the pictures above, there are only 2 parts: Body and back cover. TP4056 easily fit into the body and just need a little bit soldering for the charging pin and ready to be encolsed by the back cover.

Accidentally, i designed the top body part really thin so the light indicator from TP4056 passes through and give it a nice indicator whether it's charging or not. Green for full/no load and Red for charging.

STLs attached below

Feel free to ask questions below!

Bagi kalian yang berbahasa Indonesia silahkan kunjungi link di bawah :)

my blog project: https://www.endoxos.id/blog