Servo Controlled Word Clock v2

Version 2 of our word clock which is controlled by 114 servo motors

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A few months ago we finished building a servo controlled word clock (see link below).
In this variation of the popular clock letters are projected from the back onto a screen. Each letter is connected to a linear actuator that can be moved back and forth by a servo so that the projection changes size and focus onto the screen. Since we got a lot of positive feedback for our clock we decided to turn this into a limited product for people interested in artful technology. Version 1 of the clock turned out great but the building process was very tedious and would make it practically impossible to manufacture. In this project we will work on a complete redesign of the clock with the goal to make it more reliable and improve the assembly process that will allow us to bring our clock to the market.

We are planning the following improvements compared to the first version

  • minimalistic design based on laser cut acrylic 
  • more robust metal gear servos
  • open frame with visible mechanics from outside
  • control via android app using bluetooth low energy (BLE)
  • overall reduction of 3D printed parts for easier assembly
  • LEDs mounted on custom PCBs for easy wiring

  • PCBs ordered

    Moritz v. Sivers8 hours ago 0 comments

    We have just ordered 125 custom PCBs for the WS2812B LEDs on For the previous prototype we just cut an LED strip into 114 pieces, glued these onto a 3D printed panel and connected them again with wires. Since each LED needs 6 connections, the preparation of all wires (cutting, stripping and tinning) and soldering them took a huge amount of time. Now we will get preassembled PCBs that include JST connectors for easy wiring.

    Eagle and Gerber files for the PCBs can be found on the linked GitHub page.

  • Servo Motors and Controllers

    Moritz v. Sivers07/24/2019 at 11:06 0 comments

    This is how 120 pcs of MG90S servo motors look like. We also received 20 pcs of PCA9685 driver boards. Each one of these can control 16 servo motors and interfaces to the MCU via I2C.

  • Testing BLE Functionality

    Moritz v. Sivers07/18/2019 at 20:06 0 comments

    I recently got an ESP32 development board which will be replacing the Arduino Nano that we used for version 1. The idea is to control the clock from an smartphone app using the Bluetooth Low Energy (BLE) functionality of the ESP32.

    For a first test I used the example code written by arduinofanboy to turn an LED on/off. I was also able to control the servo motor using the same app. The next step will be to write an app that can fully control the clock and will be replacing the IR remote that we used in the first version.

  • Choosing the right servos

    Moritz v. Sivers07/14/2019 at 15:35 0 comments

    The most important part of our Servo Word Clock are of course the servo motors. For our previous clock we used SG90 nylon gear servos. Although they were labeled with the popular brand Tower Pro they were obviously cheaper Chinese knock-offs. For the new version of our clock we decided to switch to the more robust metal gear servos MG90S. To keep the price low original Tower Pro servos are still not an option but we ordered some servos from the Chinese brand MiToot. This should at least allow us to get consistent quality in contrast to ordering unbranded servos.

    The servos we ordered were delivered very quickly and I let them running for a few hours without any of them failing. While this does certainly not count as a thorough lifetime test we felt confident enough to order 120 pcs that will be used to build the next Servo Word Clock prototype.

  • Choosing the screen

    Moritz v. Sivers07/13/2019 at 11:43 0 comments

    We are planning on using an acrylic plate as screen on which the letters are projected from the back. I have ordered several samples of white acrylic with varying optical transmission. Unfortunately, the outline of the letters is always blurred on the acrylic sheets. This is because the light is diffused too much within the plates which are rather thick (2-3 mm). Therefore, the current plan is to use a thin semitransparent foil (similar to the previous version of our clock) which will then be attached to a transparent sheet of acrylic. As can be seen in the last picture, the projection has a sharp outline on the foil.

  • CAD Design

    Moritz v. Sivers07/13/2019 at 11:26 0 comments

    My colleague Fabian came up with a complete redesign of the clock's housing. Instead of using a wooden frame as in the previous version, the clock will only consist of two (or three) plates mounted on top of each other. The top plate will serve as screen while the actuators and electronic components will be mounted on the bottom plate(s).

    With this design the clock will be open on all sides so that one can observe the linear actuators moving. We are also thinking about using transparent sheets to close up the actuators so that the gears inside the actuator are also visible.

    Instead of mounting every single actuator separately on the back plate, all actuators within a single row now have a common housing. This should greatly improve the assembly process and also reduces the amount of 3D printed components.

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Vendetta wrote 07/25/2019 at 13:23 point


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Lutetium wrote 07/18/2019 at 15:27 point

Very cool to see this product-ized! Nice work!

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Richard Hogben wrote 07/15/2019 at 20:55 point


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