Thames Barrier Model Restoration
Client:
Unit22
Project Type: Models, Motors, Arduino, Hardware
I was asked to help in the restoration of a Thames Barrier model from the 70s, that used to oscillate between two positon back and forth in the head office for the Barrier engineering firm. The client wanted to restore the model visually as well as expand on this function so they could have it running consistently in the office for demonstrations, for the team and visitors.
Working with the team at unit22, they took care of the visual elements and I was tasked with developing a replacement motor system that would allow the model to move to 3 position and hold there for a few second before returning back to a home, or fully open gate positon. I would need to deliver and install a solution that me and the team at unit22 could install in single afternoon, due to the time frame of the project.
Solution
To kick things off, the 70 mechanical gear was surprisingly well kept and made fully of brass with not clear issues. The main drive chain would pas through two 90degree worm gears before driving the main gate, that would connected viva grub screw to second drive shaft. The motor seemed to powerful and stepped up in a gearing to help with torque.
After my assessment, I decide on using a large 57i stepper motor with a driver connect to the brass gearing that was already in the model. I decide this as the requirements for the install was long term and the reliability that comes from CNC motors and the type of driver and power supply means I could rely on the safety tools and solution found factories and workshops globally
The electronics would be driven by a Arduino with 3 LED indication buttons, that would flash to indicate the barrier is moving to a set position, and key places limit switch that would be true when the barrier is at its open position, the 70s model did also have some limit switches that toggle the direction of motor, so mounting for the correct position was already correct.
How it works
The script is super simple, and performs a homing function whenever power is provided, to find the limit switch, this homing feature require the connect encoder to turn clockwise a small amount then anti clockwise to find some, similar to 3d printers homing. The other functions are the buttons input, once homed the user can press any solid buttons, and the barrier will q that position had start moving , once in position for 5 second it would then return home waiting for the next button press. The project was install July 2025, and has been operating since with no issue.