How I Made My Heating Smart Without Damaging Or Replacing Anything — February 1, 2020

How I Made My Heating Smart Without Damaging Or Replacing Anything

I’ve previously mentioned that I wanted to upgrade my heating system so I could program it with more complex timings or control it form my phone. But there’s a catch: The house is rented, so the whole system must do no damage, be made only of removable parts and be installed without modifying any of the existing infrastructure.

In this post, I’ll talk about how I managed it, how it works and what the current state of the project is.

Background

My electric heating is controlled by a Timeguard RTS113 mechanical timer located awkwardly in a kitchen cupboard; it consists of a large outer ring that rotates once every 24 hours. On this ring, you push in red (on) or blue (off) plastic pegs (called tappets in the user manual) at the time you want the heating to turn on or off. As the peg passes a control spindle (representing the current time in the bottom right) it pushes it around approximately one eighth of a turn. Each eighth of a turn of the control spindle, toggles the heating on or off.

A second inner ring allows you to suppress the morning or afternoon schedule for a given day in the week. For example, you can have the heating come on at 6:00am and 7:00pm every day, except on Saturdays where it does not come on at 6:00am because the morning schedule is suppressed.

This works reasonably well, but it’s not very flexible – you pretty much a to live your life on the same schedule every day – if you deviate from it the heating is either wasting power while you’re out, or you’re freezing and have to reach into the cupboard to press the override button.

I’d love to have a smart thermostat such as Nest or Hive but they don’t support my electric heating and as this is a rental house, I’m not able to modify anything to support them.

What I Wanted To Do

The control spindle that is rotated by the pegs has a small slot on the top that can be turned manually using a screw driver to toggle the heating on an off. I can remove all of the pegs and use a stepper motor to very gently turn the spindle each time I want to change the heating state. I could then connect this to a controller that receives instructions from the internet, and write whatever software I wanted to run the schedule.

The Motor

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Using the Monoprice Voxel (FlashForge Adventure 3) With Ultimaker Cura — January 12, 2020

Using the Monoprice Voxel (FlashForge Adventure 3) With Ultimaker Cura

Recently I bought a Monoprice Voxel (a rebranded FlashForge Adventurer 3) 3D printer, and I’ve spent the last couple of weeks getting to grips with it. I’m very impressed – it works well and I’ve had a lot of fun building parts of my projects.

One interesting this about the printer is that it comes with its own slicing software called FlashPrint. This seems to work quite well, slicing all the models I threw at it and sending them to the printer. However, I was curious if it was possible to use the printer with the Ultimaker Cura slicer, which has some more advanced features and is supported more widely by the community.

I did a load of research and found some interesting topics on reddit and Ultimaker forum, I also examined the .gx files produced by FlashPrint and thoes sent to the printer by PolarCloud. I’ve gathered all this together into a this guide for using Cura, but it stands on the shoulders of a whole bunch of other people in the community, so thanks to those people you really helped me figure all this out.

Disclaimer

Every model I have printed in this way has worked well and I am very pleased. However, follow this guide at your own risk – If something bad happens to your printer, on your own head be it.

Observations

FlashPrint and the printer appear to use a custom file format for printing – .gx. This is identical to the .g file used by other printers but with some additional metadata at the top. I suspect this is the image of the model that’s shown while printing, as well as the print time estimation.

The printer is perfectly happy to print .gcode files, provided the file extension is changed to .g first. While printing a .g file the time estimation on the printer screen does not count down the remaining time, it counts up the elapsed time. Also instead of a small image of the model being shown, a generic icon is displayed.

Getting Cura

Firstly, you need to install the latest version of Cura from the Ulimaker website.

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New Project: Zero Damage Smart Heating in a Rental House — December 21, 2019

New Project: Zero Damage Smart Heating in a Rental House

This is the first post in a series documenting my attempt to build a smart heating system for a rental house. Further posts will follow as I work on it.

I have electric heating in my house, powered by a central timer from the past. The timer is a masterpiece of engineering, but is incredibly crude by modern standards. I’d love a connected system such as Nest or Hive but these systems only support low voltage trigger systems found with most gas systems, not the high voltage switching I have.

So I want to build my own, It’ll be fun, educational and greatly improve my quality of life in the winter. There’s just one thing though: I don’t own the house, so whatever I do must be easily reverted / removed / undone. Also, I’m a software not an electrician so, in the name of safety, I am not re-wiring anything or changing how it currently works.

The Timer

The timer is a Timeguard RTS113, it supports switching the heating on or off once every 30 mins by inserting a red (on) or blue (off) tappet at the appropriate time. On an inner ring it supports suppressing this schedule for the morning or afternoon for any day in the week. For example, you can have the heating some on at 6:00am, and 7:00pm every day, except on Saturdays where it does not come on at 6am.

The tappets are attached to a rotating dial, which rotates once per 24 hours. Each tappet has a lug, that as it passes a control spindle, pushes it around an 8th of a turn. As the control spindle is rotated it toggles the heating on or off.

The Plan

The control spindle has a plastic screw slot on the top to help you see its current state when programming the timer. So, in theory, I can remove all of the tappets and turn the control spindle manually (and very gently) using a stepper motor each time I want to turn it on or off.

Proof of Concept

I picked up a suitable looking stepper motor and motor controller from The Pi Hut, and hot glued a washer to the end. By holding this in place I was able to turn the heating on an off by rotating the motor with an Arduino. Now to figure our a more permanent arrangement…

Next Steps

I’ve already used Tinkercad and made a driver head to fit over the motor shaft and engage with the timer’s control spindle (replacing the hot glue blob from the proof of concept), I’ll 3D print this and see how it goes. Then I need to design some kind of support to hold the motor in the correct place so I can let go of it.

The above gif was made using Paint 3D ❤️