- There's a time and a place for batteries.
The place is the dumpster
and, even for rechargeables,
the time is eventually.
I hate them.
Most of the batteries you buy
are gonna end up leaching nasty chemicals
into the environment somewhere,
and even if you prefer coal rolling to tree hugging,
they're a massive inconvenience.
I mean, yes, yes.
In some places they make sense.
I mean, who would want a wire
permanently attached to their TV remote?
But, what in the Sam Hill is this
and where is the plug?
No, I reject your reality and I substitute my own.
But, don't get the wrong idea.
This is no Adam Savage level mod.
Converting a battery powered device like this one
to take regular wall power is both fast and easy.
I don't think this is gonna happen.
And, if you don't mind taking some shortcuts,
it can be shockingly inexpensive,
unlike sponsorships for this channel,
like the one we sold to...
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- This trend towards filling up our homes
with stationary objects
that require regular battery replacements is baffling
and infuriating to me,
because when I say regular battery replacements,
I'm being extremely generous.
A, they tend to fail in a staggered
rather than predictable manner,
meaning there's basically always something in your house
waiting for you to grab a step stool
and pop in a new power pod.
And, these CR whatever the craps they are
are anything but regular.
I mean they're mostly similar,
generally kind of button shaped, and three-ish volts,
and lithium based,
but they come in a wide variety of diameters
and thicknesses
to the point where trying to predict
and stock everything you might need
will make you feel
like you're some kind of career procurement officer.
But, then you're good, right?
Once you've got them all in your little organizer.
Well, no.
Like any batteries, they have a finite shelf life,
so you can't order too many of 'em.
You should spend that money instead
on stocking up on waffle sweaters from ltdstore.com.
We've got lots of different colors now.
To be clear, I fully support the idea
of optional battery power
or battery backups in the event of a power loss.
This is a specially important
for devices like smoke detectors
or emergency lighting that must operate
even in the event of a power outage
or for devices with volatile memory.
But, if I had a battery in every stupid connected thing
in my house,
it wouldn't matter if they all boasted
one year battery life.
It would be a weekly chore
to be going around and swapping out
and ordering new battery inventory.
Even without much smart home nonsense,
it was getting to that point at my old place,
which is why I implemented the zero batteries policy
for my new house.
Everything from security sensors, to doorbells,
to smoke detectors is hardwired,
and it was working great until Ecobee screwed me over
with the smart sensor.
Due to a questionable design choice
by the original owners of this house,
the two bedrooms that we're about to walk through
are on the same in floor heating zone.
Now, this could have been rectified during our renovation,
but it would've basically involved
ripping out the existing tubing,
which is embedded in concrete by the way,
and running new loops down to the basement mechanical room.
Yeah, that wasn't gonna happen,
which means that a single thermostat right here
controls the heating for both of those room.
That's not inherently a huge problem
given that both rooms face the same direction
and have similar sized windows
except that the thermostat
and therefore temperature sensor
is in a completely different space in the hallway.
And, my daughters were thoroughly unimpressed to find
that the new in-floor heat didn't activate for them at all,
because even though the upstairs hallway
doesn't actually have tubes running under it,
heat rises,
and enough rows from downstairs
that their thermostat
was always reporting a comfortable temperature.
Now, one way around this is offsets.
Ecobee,
and most other thermostats for that matter,
has a simple interface
that allows you to take the temperature of the room
in your desired spot,
then key in an adjustment
that allows you to account for that difference.
This is a great solution
if your sensor happens to be right next to a window
and you don't want the rest of the room
to end up being stifling hot.
But, for the girls,
it wouldn't do me a lick of good,
because the in-floor heating
and the sensor are on the opposite sides of a wall.
I'd actually end up with the opposite problem.
They'd end up with heat stroke in the middle of winter.
How embarrassing.
Thankfully, there is a solution for this.
Ecobee allows you to pair one or multiple smart sensors
to your thermostat wirelessly
to feedback data on both temperature and occupancy,
ensuring that, on average,
your room is comfortable.
So, I picked up a two pack of these
only to find out that there is absolutely no way
to power them without batteries,
and wildly this wasn't even a case
of me just buying the wrong version.
There is no wall powered smart sensor.
What the heck, Ecobee?
Fortunately, converting a battery powered smart sensor
to a wall powered one
should only take a few minutes.
Here's one right here.
By their nature,
all battery powered devices
will have their power contacts easily accessible.
All we need to do is get the same DC voltage
that the battery was supplying
to those contacts.
So, our battery here is a CR2477,
runs at three volts,
which is pretty typical of a button cell,
but not that typical of a wall power supply.
That's okay though.
We have some options.
You can get your hands on three volt power supplies
or variable power supplies,
but I promised that this was gonna be extremely cheap
if you were willing to take some shortcuts, remember?
And, that's exactly what we're gonna be doing.
Five volt low amperage USB power supplies like this
are flipping everywhere.
They cost just a few dollars to buy brand new
and, realistically,
you probably have a handful of them lying around already.
It is possible that your device
would actually take the five volt output from this
just fine.
We talked in more detail
about how to tell if a device has a range
of acceptable input voltages
in our recent video
about converting old game consoles to USB-C.
But, the smart sensor unfortunately does not.
It's pretty sensitive and we need to get exactly 3.2 volts,
which is the nominal voltage of these button cells,
into it.
So, here is how we're going to do it.
There are a number of different ways
to step down the voltage coming out of our wall wart
depending on your tolerance for ratchetness.
Our first attempt simply used resistors.
We did manage to get the voltage down to about three volts,
but what we found was that,
once the device actually booted up,
it dropped down to 1.7 or so,
which caused it to not boot up anymore.
So, instead we are going with this MIC5504 voltage regulator
which gets us down to 3.3 volts,
not quite low enough,
and this 1000 ohm potentiometer,
which is basically a variable resistor.
The total cost, about 40 cents.
To do this over again,
I would probably just buy a three volt voltage regulator
but they're less common and we didn't have any lying around.
So, this is the route we took.
The one thing to watch out for
when you're using a voltage regulator though
is that the higher power draw the device is
the more heat it might kick out
if you're inputting a higher voltage
than what it's expecting.
So, it's not like a magic, oh,
I have a thousand volts incoming,
and I need five,
and I'll just put one of these on here.
It doesn't really work like that.
It needs to be kind of close.
For wiring,
I'm just grabbing an old USB-A to mini B cable
that I don't need anymore.
And, to cleanly pass it into my device,
I'm just gonna drill a small hole
in the existing back plate.
Hole, yeah.
So clean.
Love it.
I do not have the best wire strippers
for these tiny little wires.
- [Brandon] Did you get new wire strippers yet?
- I haven't yet.
These are my old janky ones.
Honestly, a fingernail is probably better than these.
The black and red wires in here should be five volt,
but we're just gonna sanity check that real quick here.
4.95, perfect.
Now, things are about to get extremely spicy.
Unlike Dan, who did the proof of concept for this,
I do not have helping hands,
or a proper soldering work bench,
or really any of the things that I need to work on this.
So, good luck to me soldering this to that.
Okay, that actually went better than I expected.
All I have to do is about 10 more successful micro solders.
I hate my flux, I hate my flux.
This is really crappy old flux,
but the best flux is the flux you have.
And, if you don't like it, go flux yourself.
Whoops.
- [Brandon] Did you just break it?
- Did I say 40 cents?
I meant 80 cents.
I love Dan for how awesome he is,
but I hate him for how he makes the rest of us look.
If you're watching this thinking,
surely there must be an easier way,
yes,
the easier way is to not use
surface mount components like this
that are intended for board manufacturing.
Our red and black cables go into a Y splitter
and directly into our potentiometer respectively.
It goes out into our 3.3 volt regulator
and then we just need to dial in the pot
to make sure that the voltages going out
to our Ecobee smart sensor
are exactly...
Exactly 3.2 volts.
So, let's just go ahead and double check that.
3.26.
Okay, well, we'll need to adjust that.
Oh, boy.
I turned that way too much.
Okay, Gordon,
I might need you to hold this steady.
3.1 should be fine.
Okay, let's go try it.
Obviously, the stand isn't really designed
to account for this extra weight off of the back,
but that's okay.
It's a minor problem.
We're gonna solve that another day.
Let's plug this bad boy in.
Yep.
And, I guess this dresser stays that far from the wall now.
Okay, add a new sensor,
blah, blah, blah, blah, blah, blah.
Sure, fine.
Oh, I gotta scan the QR code inside it.
If I break this wiring, I'll be extremely unhappy.
Select an Ecobee device to connect to this smart sensor.
- [Brandon] Okay.
- Sure, Connect.
Is it gonna work?
There's no lights on it or anything,
'cause it's designed to run on battery for like two years
or something like that.
Is this one of those cases
where I have over-engineered the solution?
Yeah, most people probably aren't gonna do this.
Shoot, I think I have to adjust that pot again.
One of the troubleshooting steps
is to bring the sensor closer to your thermostat.
Maybe that's the problem.
- [Speaker] Nope.
- Okay, it's basically at exactly 3.2 now.
I wonder if it's dead.
This may have been more trouble than it was worth.
Let's try a different sensor real quick here.
It's one of those things
where I hate every moment of it while I'm doing it,
but as soon as I'm done,
I can't wait to do it again,
you know?
Why is my hobbies this?
Why are you 4.2 volts?
Well, I sincerely hope I didn't fry this thing.
3.175.
Okay, let's try it.
Boop.
Girls' room.
Can...
- [Speaker] Nope.
- [Dan] Hello, go ahead?
- Hey, you're on speaker.
I'm at my wits end here.
- [Dan] Okay.
(upbeat music)
- [Dan] Could be that it's registered
to the the Ecobee here?
- No, I tried.
I tried popping your thing into a different one.
It's at 3.200 volts,
exactly what you specified.
I accidentally ran it at a higher voltage momentarily.
It was at like 4.5.
Do you think I just fried it?
- [Dan] No, I was doing that a lot.
What you could try doing is bur lower
or like increasing the voltage,
turning down the pot until it spikes up to four
and then increasing it from there
to bring it back down to 3.2.
I think it has a large bit of draw right at the start
and that screws with our little jank system.
- Oh, I think we've reached the point in this video
where I can't say that I would recommend doing this.
- Hey, guys, Dan here.
I figured out what was going wrong with Linus' Ecobee.
One of the little tiny wires inside the USB end
actually broke
and so we weren't getting the full five volts
that we needed
to make it run at all.
Linus actually did a great job
with the impossible soldering task that I gave him.
I hope you can appreciate
just how absolutely tiny
some of these SMD size components are.
I mean honestly, could you soldier onto that?
It...
Like in your carpet?
That's nuts.
These do come in larger versions,
but we didn't have any on site,
so I had to kind of make do with what we had.
However, while troubleshooting
I actually did find a better solution
that's kind of Linus proof.
Look at this size of this guy, it's giant.
I don't even have to use tweezers to hold it up.
Far easier.
I've done a little test setup here,
so you can kind of see how they work.
It's really neat.
We can use three of them in series
to step down the voltage to exactly what we want.
If we wanted a lower voltage,
then we could just add more.
In the first section before the diode,
we're getting our five volts.
That's directly right out of our USB wall wart.
And, at the final position, we're getting 4.3.
Now, that's not the three volts we need,
which is kind of weird.
Because, there's no current being sucked out of the diodes,
the circuit kind of doesn't know what's going on,
and the power supply doesn't know what's going on,
nothing's being drawn.
As soon as we add our Ecobee sensor in here,
on our first section, we're getting 5.1,
on our second section, we're getting 4.7,
and our third section, we're getting 4.3.
and then finally on the output,
we're now hovering around four volts,
so we've stepped down like a whole volt.
But, these Ecobees are ultra low draw devices.
These draw like 0.005 of a milliamp,
which is almost nothing.
When we're about to pair them,
they're actually drawing a lot of current.
They know that they're not paired
and they're drawing 30 to 50 milliamps,
and that's kind of what we're seeing
when we're dropping down to our three volts initially.
Every four to 10 minutes,
you get a little spike of 7 million.
This is one of the reason Linus was struggling so much,
because it's asking for wildly different amounts of current.
I think this is kind of one of the weirder devices
in this category
to convert to battery power.
I think both of us learned quite a lot
on this interesting little project.
And, here's another little finished one I did.
I'm happy to be done with this (censored).
However, Linus doesn't know any of this,
'cause he was trying it about a week ago.
Let's see how he does.
- Here's what we're gonna do, okay?
We're gonna unplug it.
Oh, shoot.
I just melted a bunch of the plastic housing.
Oh, it still fits.
Thank goodness.
Now, we just need to go into home assistant
and see if we're actually getting a readout from it.
Holy crap.
I think it might be working.
Let's take it into the room.
Holy crap.
I will...
I will come up with a better system for this later.
And, we finally got a temperature update.
It's about a 20 minute cycle time,
which I guess makes sense
on a device that's intended to run for years
on a button cell.
But, anyway, the point is it's flipping working,
which means I don't have to run the heat pump
in the winter anymore.
See you later.
Okay, wait, yeah.
How does this work?
(upbeat music)
I'm so excited this worked.
I'm not excited to do up another two of them
without Dan's help,
but I am excited to tell you about our sponsor.
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That's a pretty...
This is a pretty good deal.
- If you guys enjoyed this video,
maybe go check out the one
where Jake helped me hack together
this whole Ecobee home assistant thing in the first place.
It's pretty interesting actually.
These are...
This is not how these things are intended to be used.
(upbeat music)