Designing a dark LED stylus pen

Project Info


The client requested our company for designing a special dark LED stylus pen that could write at nights or in some areas with insufficient light. The design was to be later prototyped and therefore it had to meet the requirements given by the client.


The main requirements for the project included the followings:

  • The pen’s internal battery had to be capable of powering the system for a long time, like in such applications as mountain climbing where for there is no access to the grid power for the charging for a long time.
  • The aesthetics of the pen had to be considered so that it could compete with the existing similar products in the market.
  • The final design had to be cost-cost effective.


Based on the client’s request, our engineers started working on a pen enclosure satisfying the aesthetic condition. Having finished the design, they worked on the electronic part according to the following steps:

  1. They designed a mechanism by which when there was a pressure on the tip of the pen, the electronic board could power the LED and turn it on.
  2. They also considered a high power small size battery that could power the LED.
  3. The board was then tested to make sure that it could work in different conditions.
  4. In order to meet the power condition and extend its working time, the designers added a solar charging system in addition to the small battery embedded in the body of the pen. This helped the charging of the main battery and storing energy even when posed to a week light. The small PV panel was installed in the transparent cylindrical part of the enclosure in the middle of the pen

The client was satisfied with the design as it met all of his requirements and proceeded with the prototyping of the product.

David Jones
May 20, 2018
Mechanical Engineering