One client last year assigned me the task of technical supervision of a smart watch project designed and produced in collaboration with a Chinese factory. After two years of working with the factory, the client discovered, at the final stages, that the factory had violated contracts preventing them from reselling the same product. As expected, the factory refused to deliver any source files for the embedded program so we could continue development without them.
The project owners eventually realized that the product quality was poor both in terms of software and electronics, and also discovered the factory had not adhered to agreements regarding reselling the design. However, they had already lost time and money. They decided to stop working with the Chinese factory and begin studying the development of a new version, assigning me this task.
Through this experience, I learned many lessons, which I will share in this report, focusing on component selection and interacting with manufacturers in China, or what is called an Original Equipment Manufacturer (OEM).
The first mistake was on the part of my client, who repeatedly ignored my advice that the factory was not performing its tasks properly. Tasks that should have taken two days were taking a month, and repeated errors appeared frequently in the software.
Although the client decided to continue cooperating with the factory despite discovering the deception, this collaboration reached a dead end when the factory informed us that it did not possess the source files for the embedded program and had developed it with an independent developer, which also violated the agreement.
The client then decided that we should look for a new partner. This time, I told them that we must choose carefully and keep the key assets in our control, primarily the embedded watch software.
I proposed a development plan to find a manufacturing partner in China that would allow us to develop part of the embedded program related to the client’s unique smart watch features, including programming the user interfaces (UIs).
I conducted in-depth research on potential manufacturing partners, contacting at least 20 companies via email, and used Reddit communities such as r/hwstartups, r/embedded, and r/AskElectronics to get recommendations from real people rather than ads.
I also researched open-source watch projects such as zswatch and studied the new version of the famous Pebble watch. They reproduce it and share many technical details, especially after Google released the source code for the old watch. Through this, I discovered a Chinese microcontroller called SF32LB52 with an open-source development environment that includes most required features, is low-cost, and supported by the LVGL library widely used for smart watch UI design, even in Xiaomi watches. I also contacted hwtrek.com, which connects you with reliable Asian manufacturing partners; you only need to send them an email with details.
I conducted a study on the most suitable microcontrollers for smart watches, identifying candidates that must be low-cost, have a graphical processor (eGPU), sufficient memory, and support external memory.
I also studied key electronic components such as the magnetometer and IMU, especially since the watch includes a digital compass that must work reliably. I found that Chinese chips are difficult to research through traditional methods—they are not available in usual sources, and without Taobao, it is hard to know their prices (Taobao is difficult to use outside China). I also discovered a Chinese version of LCSC (item.szlcsc.com), which contains Chinese chips not available in the global version of the site.
In my plan, I proposed developing the electrical schematic by first creating a large-form-factor prototype PCB, which the manufacturing partner would then convert into a suitable PCB for the final watch case. I prepared a Product Requirements Document (PRD) detailing the product specifications to allow the manufacturing and development partners to provide accurate quotations.
After about a month of calls and interviews with potential partners, I reached the following conclusions:
- One of the biggest obstacles to working with manufacturing partners is the Minimum Order Quantity (MoQ). Most partners and factories refuse to cooperate if the MoQ is less than 100,000 units.
- Do not trust a partner without conducting a factory visit, either in person or through a reliable third party, and verifying their legal records.
- Language barriers are one of the major obstacles when dealing with Chinese manufacturers. Either a capable translator is required, or you must find a partner who understands English, which reduces available options to less than a third.
- Chinese factories often attempt to steal designs, so be wary of any partner showing unusual interest in your product idea. It is better to maintain control of key assets such as software and mobile apps to prevent easy copying.
- Finding a manufacturing partner may take months. It is recommended to start prototyping before securing a partner, although the partner may still play a role in some design decisions.
