How’s it going with the fan controller design?
I was hoping for a Christmas miracle! 
How do the results compare with commercial fan convector radiators assuming the exisiting radiators all need replacing due to being 1970s?
Sorry, Santa got held up a bit. I have noticed a few flaws in my design that needed fixing. This is 90% done now. I have redesigned the whole electronics so it can be cheaply manufactured at JLCPCB for less than 10€/PCB, plus the plug-in controller. Once this is finished, I plan on placing one big order.
3 Likes
I have a few measurements how much they increase power but would not put so much trust in them to inform on radiator size for a new install. The combined setup with Type 33 rad + fan will be cheaper than going with a commercial product.
1 Like
Great news! Hyped for the release.
My goal is to increase the output of a 1400x600 K3 rad in the bay window of my living room; it’s located behind a sofa, so radiant output is almost non-existent, and the room sits at ~1C below the rest of the house. Hoping that 8x 140mm Noctua fans running at ~500rpm will boost convection output enough to make up the shortfall.
That will be sufficient to get the extra degree. One of the flaws was not having sufficient sockets for fans, the new design has 8, so perfectly suited for your setup ;).
1 Like
I put 8 fan connectors and the temperature sensors can now be attached with screw terminals to avoid having to crimp a connector to them. Also, there’s one DS18B20 sensor already on board. I’ll review the design again in the coming days to avoid any stupid mistakes and then order a first testing batch.
4 Likes
I’m suddenly interested myself. I have a room which has failed to heat sufficiently over the past few cold days, and which I really think that, with a bit of help from fans, could produce the heat required.
Would it be possible to swap the barrel DC power connector to a 5V USB-C type? This would make for a neater install in combination with USB wall sockets…
2 Likes
The fans are 12V, so that’d be kind of tough. You can negotiate different voltages over USB-C but I never looked into that
1 Like
I also have a big radiator under a living room bay window that didn’t seem warm enough.
Adding (commercial) fans underneath does seemed to have helped with the room temp.
2 Likes
I had a look - you can buy 12 V “Trigger cables” that are barrel jack on one end and USB-C on the other. They integrate the necessary hardware to negotiate the voltage with the wall wart and then output the 12V on the barrel plug end. It’s a good idea to move to USB-C, but I would see that as further down the road as integrating the hardware to comply with the USB-C specifications is not trivial (to me at least). I’d really like to have USB-C and a full Esp32 instead the pluggable Atom lite on the PCB in the future but I don’t have the time for that currently.
4 Likes
Thanks for the reasoning, makes perfect sense. I’ll use a trigger cable from my 3A USB wall sockets.
Really looking forward to using your controller, thank you for working on it!
1 Like
I still have TADO’s on all rads, so I can use these to read the room temperature and then stop the fansbased on those
You have to check whether they deliver sufficient power. It needs to be USB-C PD (power delivery) on the wall wart, otherwise they cannot deliver the power. If the rating is 3A at the standard 5V USB voltage that would be pushing it, as one 140mm fan can draw up to 0.3A @ 12V, i.e. 3.6 W. With 8 fans + some headroom you need a 30W supply to run them at full power.
1 Like
I ordered the fully assembled prototypes from JLCPCB last night and hope to have them by the end of next week. If the tests are successful, I will place another order and could ship them to anyone interested. The more I order, the cheaper it gets. An order of 25 would result in 10€/PCB, plus another 10 € for the Atom Lite controller, so overall around 20€/piece + shipping. Cost optimization comes next, but I think this is not excessive. I’m just not sure about the process of shipping to the UK from the EU - I guess this would just be a private parcel without any customs involvement.
Softwarewise I’m currently using ESPhome in conjunction with Home Assistant. I guess a more standalone solution is needed as not everyone has HA.
1 Like
There is latitude for some “edge logic” in ESPhome [I am sure you know this anyway].
For example, I have ESPhome deployed on smart plugs which pings something and power cycles if it stops responding for so many minutes.
ESPhome also can have its own web interface.
1 Like
The web server component is a great idea, I hadn’t considered this. I’ll try right away to activate it for one of my devices to see whether the memory suffices.
1 Like
Excellent news! Count me in for 2x units, possibly more depending on how effective the fans turn out to be.
1 Like
