SpotClock 2 displays live gold, silver, and platinum spot prices on an array of custom 7-Segment displays.
The 7-Segment displays shows the price in red, green, or magenta representing price down days, price up days, and holidays/weekends.
The controls area consist of a power switch, element select button, and Wi-Fi connection indicator.
The display segments are 3D printed from white PLA. Unfortunately, the white material causes the display to washout making the digits difficult to read due to the lack of contrast. For this reason I consider this a failed project despite the technical project aspects functioning correctly.
The three elemental indicators inform the viewer which element’s price is being displayed.
SpotClock 2 uses 2020 aluminium extrusions creating a sturdy frame with multiple attachment points for various brackets.
Behind each plywood panel are seven WS2812b strips. Typically projects are designed to allow for disassembly of all major components in case of part failure, damage, or redesign. Unfortunately, due to a hastily design phase, the 7-Segment displays were not designed to be removable allow for a quick reprint and replacement to be unlikely.
The MeanWell power supply is secured with custom 3D printed brackets and provides enough power for the 124 WS2812b LEDs (most fixed to one color and brightness software limited).
The MCU is an ESP8266 (NodeMCU) provides Wi-Fi connectivity, JSON parsing, and LED driver ability. Due to timing issues, the ESP8266 was not able to drive the strip length of 105 LEDs – a flickering issue occurred around LED 42. Therefore the strips needed to be shortened and connected to multiple pins. Due to limited pins LED strips (7-Segment display, element indicator, dots, name plate, connection indicator) were daisy chained in such a way the resulting firmware suffered development slow downs and awkward code.
The SpotClock 2’s Wi-Fi and system parameters are stored on a SD card. The image above shows the custom bracket holding SD card module in place.
The connection status indicator’s LED wiring is not particularly well done as the the exposed pins could cause future problems due to shorts. Using heatshrink tubing is required for a satisfactory wiring job.
Another point of contention is that the power distribution method is crude, albeit effective. Power distribution being a regular requirement in many projects, custom drop in PCBs will be developed for future projects.
The wall hanging bracket is effective in terms of strength and the ability to shift the frame to prevent tilt.
The corner brackets are 3D printed and have the strength to hold the frame square.
The above image is example of the washed out display due to the lack of contrast.
Source code and design files: https://github.com/reubenstr/SpotClock2
Not recommend for new designs.
See the QuoteBot project for up to date ESP32 based stock quote framework.
Update (3/15/2021):
An updated version of the SpotClock 2 is being planned with removable 7-Segment displays printed in black. A fix for the WS2812b strip length flicking error will be attempted and if the error persists an ESP32 will be deployed. The update will incorporate firmware enhancements utilized by the QuoteBot such as multiple Wi-Fi credentials, NTP local time, market hour detections, dimming, etc. Power distribution PCBs have been developed and will be incorporated into the new version.
