The Freshening Part 5

So it's about time I got this project fully wrapped up, and a little ahead of schedule as I managed to get an early start today which meant I could burn some time before lunch, and thus before the attic turned into an inferno that would cook me alive as soon as I poked my head up above ceiling level.

Of course, the first task didn't even take place in the attic itself, but rather in my car hole, where I bent up a piece of sheet metal into a 5 inch round splice.

Fun fact: you can make round things on a sheet metal brake... Well, sort-of-round things. Round enough.

Anyway, that piece goes in between the too-short piece of duct I installed a few days ago and the new piece of duct that arrived on my doorstep.

So this area over here is no longer a hideous octopus of aluminum foil ducting.

And what did I do with the remaining 15-or-so feet of duct from the 25 foot box?

I shoved it back in the box. I'm sure I'll find a use for it at some point. It can live up here until then.

Speaking of boxes, I installed the relay box which allows me to adapt the 120v timer switches I installed last time to the 24v control lines that the HRV uses.

It's just a pair of relays with 120vac coils (which is apparently a thing) wired up exactly how you'd expect them to be.

And good news: even at full zoot with the "Taco Tuesday" button switched on, the HRV is still barely audible down in the occupied portion of the house. In fact, I think removing the duct-o-pus from the output actually made it a bit quieter than it was initially, which is pretty sweet.

So the only other question is: how efficient is this HRV? Well, it was a little over 28c outside the other day so I pointed my thermal camera at the fresh air vent.

Hmm. Well, I guess I can't really expect miracles when there's only 4 degrees difference between the inside and outside temperature. And, let's face it, this is California; the main goal here, which I achieved, was getting more air circulation inside the house without having to open the windows and let a bunch of pollen and pollution in.

But while I've got the thermal cam out, let's see how the insulation in the car hole is performing (which is still an ongoing project).

Well now that's a bit more of a dramatic difference. The face of the insulation (left) is only 25c while the underside of the roof (right) is roasting at 42c.

Now that the HRV project is done, I'll hopefully be able to wrap up the insulation project over the next few weeks before spring really kicks into high gear and the hot days become more inconveniently frequent.

But in the meantime I've got some fresh air to enjoy.

Seeing Stars

When I got my microscope, I foolishly decided to get a stereo binocular unit instead of a trinocular unit which has a third "eyepiece" for a camera to be mounted to. For most usage this isn't a big deal as I'm only using my own two eyes to look through the microscope, but I've found that occasionally I'll want to shoot a photo or video of something I'm looking at up close, and the lack of a camera mount puts me in an awkward position.

I thought about trying to find some sort of adapter to be able to mount a smartphone to look through a microscope eyepiece, but the fact is that the market for people who bought a microscope but need a camera feed and didn't get a trinocular is pretty small and not worth serving.

On the other hand, the market for people who bought a telescope and want to take pictures through it with their smartphone is much, much larger.

And wouldn't you know it, but the eyepieces are, externally at least, pretty much identical between telescopes and microscopes. The field of view isn't really amazing mind you, so I have to zoom in a bit to avoid the circular cropping, but all told it's pretty easy to set up and yields some perfectly usable images.

It's certainly worth the $20 I spent on it.

The Freshening Part 4

When we last left off on our HRV installation adventure, we were staring at the underside of a piece of cardboard blocking up a hole in my ceiling that was a bit too large for the vent that was about to go into it.

Since this will be another long one, click through to continue reading.

Caulk, Robot Caulk

Recently I had cause to dispense some construction adhesive in order to stick something to another something (as one does). This reminded me that squeezing construction adhesive out of its tube with a regular manual caulking gun is quite a bit more difficult than I'd prefer to put up with. So, I hired a robot to squeeze it for me.

I was almost a little worried when the new electric caulking gun stalled before squeezing any adhesive out of the tube, but after clearing up a bit of dried up adhesive from the tip it was able to dispense it without too much difficulty.

And just for context, it's not like I'm lacking in forearms strength by any measure, I can squeeze the handle on my caulking gun hard enough to basically collapse it, and the construction adhesive will just barely, ever so slowly, ooze out of its tube.

So the fact that this new caulking gun can squeeze out a healthy bead at a respectable rate is nothing short of impressive.

I suspect I'll still use my manual caulking gun for most regular caulking jobs as it's much lighter, a bit more compact, and absolutely sufficient for the job. At least, I will after the novelty of using this new one wears off. But for construction adhesive in particular, I'm going all in on electric power.

The Freshening Part 3

Parts have arrived, the week has been booked off, so let's get things moving for real. We'll start by yeeting the HRV up my shiny new attic ladder.

But because this will be a long post, not until after the break. Click through to continue reading.

Feet Pics

In a previous blog post I introduced the function generator that I recently picked up. Having been formerly used in a rack mount setup, it didn't have any feet, and so was sitting directly on its bare chassis on the overhead shelf of my workbench.

This isn't especially ideal given that there's cooling vents on the bottom of the unit, so I ordered up some feet to lift it back up to its proper height.

They just snap into the trio of holes on the bottom of the unit.

And now the function generator is sitting much nicer on the shelf with plenty of air space underneath.

I'm still contemplating one other upgrade for this unit, but that will have to wait for a future blog post, depending on how things work out.

The Freshening Part 2

If I'm going to bring fresh air into my house, I want it to be actually fresh, and that means I'll be filtering out all the pollen and pollution that tends to be mixed with the outside air. To do this, I'll need a filter and, more importantly, a plenum to install the filter into.

So it's back to the sheet metal grind to use up the other ~3/4 of the metal I cut up last week. A basic box is a good place to start.

As we can see this is sized precisely to fit a 12x20x1 filter diagonally inside the 1 inch flange. Coincidentally, the size of plenum needed for this fit is 12x20.

Go figure.

Anyway, the removable fingers of the box and pan brake are really coming in handy here, especially when it comes to the double-fold on the door panel.

It's actually going to fit folded side out to the front of the plenum so that the flat panel sits up against the side of the filter, otherwise the air would just blow right around it through the gap.

And we can also see the rails in this picture that the filter will slide into.

Those rails get riveted to a set of corner panels, and a pair of braces goes lengthwise between them to support the filter and block the air from going around the edges.

And the whole assembly will look roughly like this.

But that's going to need a lot of rivets, so before we get there let's take a quick newt break.

And refreshed from that, I'll add the cross breaks to the panels. I had initially contemplated not adding them as some of the panels were slightly too large to fit into my brake diagonally, but in the end I decided to go for it and employed the other method for adding cross breaks: using a window screen roller.

Which works surprisingly well, all things considered.

Then, about a hundred rivets later, everything is secured together nicely.

Was it actually 100? I don't know, feel free to count up the stems and let me know.

I do still need to attach the door to the plenum. I already have the hinges and latches, but I want to get the weather stripping first so I can space things out correctly.