Race time semaphore - "Timekeeper"

[burgic]

The one of my freelance products that I sell the most is the "Timekeeper". It is actually an ordinary clock (0-24) with several features, used mostly on marathons, half-marathons and similar activities.
The feature list was (and still is) extending according to the customer needs (upcounting mode, downcounting mode, GPS synchronization, manual RTC calibration, device setup and control using the encoder, device setup and control over PC using the UART, etc.). Remote control is currently not supported, but it is planned for the future.

The main board is based on STM32F100 MCU. Internal RTC with an external 32,768 KHz crystal is used as a time base. Depending on the product variant a GPS module (MTK3339) can be connected to use it's PPS signal to avoid the drifting of the time due to the RTC and its external circuitry. Since the time is quite stable with on-board components (XTAL + capacitors) a GPS module is usually not required by the customer. The display is driven by TLC59282 which is located on the display board. Each display board contains two 7-segment digits and an output connector for the colon, which is an additional board.

Some of the pictures from the "field" and PCB schematics and layout of the main board are attached.
The PCB schematics and layouts of the digit and colon board will be attached in the next post.


Posted on: February 13, 2020, 05:48:18 05:48 - Automerged
In the meantime I found better pics from the gerber viewer for the main board.
Actual pics of the boards will be uploaded when they are delivered from the PCB manufacturer.

[Martin Miranda]

nice project! i made a similar one for a arcade game.
the rtc is ok. but i needed more precision in the mS.
https://www.romanblack.com/one_sec.htm