I'm still working on a new design for a boost filter, which is looking good so far, though my first prototype print does have a few errors I need to fix. I think the design will work OK though, and the 8038 fan fits. I'm still waiting on an OLED screen with 4 buttons and a couple other parts for the design though.
But since the boost fan is coming together, I thought about making a more universal window exhaust setup (than my doggie door exhaust duct). The doggie door duct works really well, and has been going strong for a couple years now, but I never released it, since I was waiting to really test a boost fan to go with it. Both use 2.5" hoses, so they sort'a work together. The downside of a doggie door vent however is that not everyone has a doggie door, and some are used by actual dogs. So I started adapting the design to a window and after a failed first attempt, I think this next one may be a winner. The design utilizes a similar flapper setup to close off the vent when the fan is off (but that part is optional). The design is intended to be lower profile, so the window can be opened just about 30mm, and there will be some 250mm inserts to fill the gap. These inserts are in the 1st and 2nd pics, and appear like stairs since they are arrayed next to the larger insert. The inserts will attach to the vent, and each other, with some additional sizes in 20mm increments, so hopefully most window sizes can be accommodated. My hope is that a window could be opened just enough to get this in place, some weather sealing tape could be run around the parts which go in the window, and then the window could be secured closed with a slide latch or even just a stick to deter the bad guys. The whole unit will also be easily removable, so it can be used temorarily while printing and then removed, with only a single wall bracket and one knob that will be needed to take it down or put it back up.
I've also designed a mirrored version, so it can be used on left or right side opening windows, as well as on the bottom of a window that opens vertically. This is all of course what is intended, and none of this has been tested, but the design seems OK.
I have one problem though, and that is I don't really need this design myself. But I can test it, and have a family member who may be able to use it, so I do plan on test printing it - but that will be after I get the boost fan done.
But since the boost fan is coming together, I thought about making a more universal window exhaust setup (than my doggie door exhaust duct). The doggie door duct works really well, and has been going strong for a couple years now, but I never released it, since I was waiting to really test a boost fan to go with it. Both use 2.5" hoses, so they sort'a work together. The downside of a doggie door vent however is that not everyone has a doggie door, and some are used by actual dogs. So I started adapting the design to a window and after a failed first attempt, I think this next one may be a winner. The design utilizes a similar flapper setup to close off the vent when the fan is off (but that part is optional). The design is intended to be lower profile, so the window can be opened just about 30mm, and there will be some 250mm inserts to fill the gap. These inserts are in the 1st and 2nd pics, and appear like stairs since they are arrayed next to the larger insert. The inserts will attach to the vent, and each other, with some additional sizes in 20mm increments, so hopefully most window sizes can be accommodated. My hope is that a window could be opened just enough to get this in place, some weather sealing tape could be run around the parts which go in the window, and then the window could be secured closed with a slide latch or even just a stick to deter the bad guys. The whole unit will also be easily removable, so it can be used temorarily while printing and then removed, with only a single wall bracket and one knob that will be needed to take it down or put it back up.
I've also designed a mirrored version, so it can be used on left or right side opening windows, as well as on the bottom of a window that opens vertically. This is all of course what is intended, and none of this has been tested, but the design seems OK.
I have one problem though, and that is I don't really need this design myself. But I can test it, and have a family member who may be able to use it, so I do plan on test printing it - but that will be after I get the boost fan done.
2/2/2026: This project has become + one more now, since I decided to integrate the booster fan with the duct, as an option. It actually will probably make more sense than an inline fan in most cases too. The updated design appears mostly completed, and I have tested several of the electronics holders and the screen parts. It's always a bit of trial and error to get things to fit just right when dealing with electronics and boards, but getting the screen and buttons to work just right took three tries. The cool thing is that I now have a working reference design and have modeled the boards I'm using, which will help with future projects. I still have to tweak the buck converter mount, but it should be a simple fix.
My next step is to get the automation working in a breadboard setup, and make sure the sensors function. I'm really hoping I didn't bite off more than I can chew with this though, since I'm gonna lean on ESPHome and help from AI to get started. It's been a while since I've done much with Arduino or other micros, but I hope it will start coming back as I go. So far, I've just loaded up Home Assistant, with the HA-Bambulab integration. HA seems a bit clunky, but definitely has gotten better since the last time I tried it out. Still though, I think the UI is still pretty cluttered, with everything on blast by default, especially with the ha-bambulab integration. I know there are ways to clean it up, but they are also a bit clunky, so for now I just shut off all the stuff on my "Overview" page to clear the noise out. I probably won't be using HA for anything else though, so won't need to deal with it, aside from getting the filter integration set up.
My next step is to get the automation working in a breadboard setup, and make sure the sensors function. I'm really hoping I didn't bite off more than I can chew with this though, since I'm gonna lean on ESPHome and help from AI to get started. It's been a while since I've done much with Arduino or other micros, but I hope it will start coming back as I go. So far, I've just loaded up Home Assistant, with the HA-Bambulab integration. HA seems a bit clunky, but definitely has gotten better since the last time I tried it out. Still though, I think the UI is still pretty cluttered, with everything on blast by default, especially with the ha-bambulab integration. I know there are ways to clean it up, but they are also a bit clunky, so for now I just shut off all the stuff on my "Overview" page to clear the noise out. I probably won't be using HA for anything else though, so won't need to deal with it, aside from getting the filter integration set up.
2/2/2026: I spent some more time today on this design, and made a few more optimizations for printability. The parts appear to slice OK. and there will be minimal supports needed. The related booster fan design is gonna be the first test of this concept, and if it works as planned, I will then try printing this window blower duct and test it as well. But between that booster fan and this design, I will need to complete testing on my H2C spares case, so this is 3rd up to bat. This design should be an easier build though, since there is much more room for the electronics components, which will be semi-modular in the way they install.
2/12/2026: This project had to take a pause while I wrap up the H2/P2 Spares Case Update. That project is gonna be done this week or early next week, so I expect to get back to this one then.
4/29/2026: Well I guess I wasn't very truthful with that last update, but really a few things popped up, and some other projects as well, so this one got sidelined again. But the time has let me think of a few things I should change with the design, so that may be a plus. This one however is still at the back of the queue, behind three other projects that I haven't posted about, but will hopefully be done soon.
6/6/2026: I haven't forgotten about this design, and am making some progress on the electronics component, with a somewhat related project (which this one will directly benefit from). The related project is an update to my Bento Box clone, to add an ESP32 running ESPHome, which I will then integrate with HA-Bambulab to add some intelligence to when the filter runs. The whole thing is being "vibe-coded" using AI, since my coding skills are very rusty (and what they were at the peak was nothing to be very proud of anyway). I'm pretty impressed though, and some of that old knowledge is coming back into my head as I work though the project.
Pardon the messy breadboard, it's been cleaned up quite a bit since I snapped these, and I've since soldered all the headers onto the board. The ESP32-32E dev board I'm working with lacks much of any documentation, but I think I've gotten all the pins figured out (and will post that as an update seprarately when I'm certain of it). The only reason I went with this dev board was due to the onboard MOSFETs, which I'm using to control a pair of non-pwm fans on the Bento Box clone (since 4 wire 5020 blowers seem to have disappeared from AliExpress lately). But with the window vent filter, any old ESP32 board will work, since I can use a PWM fan with that design. The VOC sensor I'm using is one of these, however it suffers from an ugly feedback problem due to the VOC sensor heating the onboard temp/humidity sensor, which is used to calibrate the VOC sensor. It's probably good enough to see a trend though. I may try adding a second temp/humidity sensor to fix that issue, but really it's not a big priority. In the first pic the sensor was still "warming up", which can take a long time, but when it does it starts showing actual data.
This will be the last post on the window vent filter for a while (probably several weeks), since I want to get the other designs finished and posted. Fortunately the CAD is mostly done, so I will just need to print and test it when I circle back. The electronics should be an almost copy/paste from the setup I'm working on for the Bento Box clone V2, so that should also help.
4/29/2026: Well I guess I wasn't very truthful with that last update, but really a few things popped up, and some other projects as well, so this one got sidelined again. But the time has let me think of a few things I should change with the design, so that may be a plus. This one however is still at the back of the queue, behind three other projects that I haven't posted about, but will hopefully be done soon.
6/6/2026: I haven't forgotten about this design, and am making some progress on the electronics component, with a somewhat related project (which this one will directly benefit from). The related project is an update to my Bento Box clone, to add an ESP32 running ESPHome, which I will then integrate with HA-Bambulab to add some intelligence to when the filter runs. The whole thing is being "vibe-coded" using AI, since my coding skills are very rusty (and what they were at the peak was nothing to be very proud of anyway). I'm pretty impressed though, and some of that old knowledge is coming back into my head as I work though the project.
Pardon the messy breadboard, it's been cleaned up quite a bit since I snapped these, and I've since soldered all the headers onto the board. The ESP32-32E dev board I'm working with lacks much of any documentation, but I think I've gotten all the pins figured out (and will post that as an update seprarately when I'm certain of it). The only reason I went with this dev board was due to the onboard MOSFETs, which I'm using to control a pair of non-pwm fans on the Bento Box clone (since 4 wire 5020 blowers seem to have disappeared from AliExpress lately). But with the window vent filter, any old ESP32 board will work, since I can use a PWM fan with that design. The VOC sensor I'm using is one of these, however it suffers from an ugly feedback problem due to the VOC sensor heating the onboard temp/humidity sensor, which is used to calibrate the VOC sensor. It's probably good enough to see a trend though. I may try adding a second temp/humidity sensor to fix that issue, but really it's not a big priority. In the first pic the sensor was still "warming up", which can take a long time, but when it does it starts showing actual data.
This will be the last post on the window vent filter for a while (probably several weeks), since I want to get the other designs finished and posted. Fortunately the CAD is mostly done, so I will just need to print and test it when I circle back. The electronics should be an almost copy/paste from the setup I'm working on for the Bento Box clone V2, so that should also help.
6/10/2026: The ESPHome / Home Assistant automation seems to be working, with the fans being controlled by my X1C's "Print status" entity in Home Assistant. The fans can only be controlled by Home Assistant when the logic running on the fans locally has a flag set to allow automatic control. That is done via a menu which requires a 3 second button press of the "enter" key to set the automatic control mode to on or off. That makes the auto control an intentional choice, and it can be canceled out by the user by pressing the main button at any time (which turns off the fans, and reverts to manual mode). When in manual mode (auto being disabled), the filter is controled locally by a main button which cycles from off-high-low.
I'm still doing some testing to verify things, but so far I've not found any serious issues (and those that were found have been resolved). I'm a novice to using Home Assistant (and my "Overview" screen on HA is a mess lol), but things are statring to click.
There will also be some 24h history graphs, which will allow tracking a rough trend of how temps, humidity and TVOC change over time. These will be accessed by menus on the filter, but I expect that HA could also be set up to track this data on a dashboard as well.
I'm still doing some testing to verify things, but so far I've not found any serious issues (and those that were found have been resolved). I'm a novice to using Home Assistant (and my "Overview" screen on HA is a mess lol), but things are statring to click.
There will also be some 24h history graphs, which will allow tracking a rough trend of how temps, humidity and TVOC change over time. These will be accessed by menus on the filter, but I expect that HA could also be set up to track this data on a dashboard as well.
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