fest

14 ms·

91.
by fest 4y ago
Standard WiFi AP only broadcasts short identification/presence beacon frames once a second or so. With a firmware that supports TX99 (a mode where radio is transmitting all the time, typically used for testing/certification proces
92.
by fest 4y ago
When I set up my Fronius inverters, I did connect them to Ethernet, but disabled any cloud features and set up a simple script that fetches the stats I'm interested in and stores them to a local influx database. I didn't go as far
93.
by fest 4y ago
It really depends on your starting point. If you have a perfectly serviceable means of heating that you are happy with, then it's a straightforward cost analysis (cost of consumables for the current heating method vs cost of electricit
94.
by fest 4y ago
Brine temperature varies over the heating season by up to 10 deg C. I really tried to verify the horizontal coil length and installation depth recommended by installers from the first principles, but I had to give up, as there were just too
95.
by fest 4y ago
"That's OK, I learned a ton while doing this" :)
96.
by fest 4y ago
While I do agree that it was true a year ago, I wonder if it holds true for current electricity prices? My considerations for going with ground source heat pump were: * the maximum amount of solar that I could install is enough for ground s
97.
by fest 4y ago
Yeah, I have travelled that road too often (hmm, looks simple, I bet I can make it for half the cost- and a year later I have spent way more even disregarding the cost of my time and still only have a barely working thing) to know how that
98.
by fest 4y ago
For horizontal designs yes- the rule of thumb is the brine coil area should be around 3x the heated area. However, the vertical bores don't need much area, just expensive drilling work.
99.
by fest 4y ago
Modern heat pumps drive the VFD and circulation pumps as needed (i.e. the pumps run slower when the heat demand is low). The main factor for good efficiency is low output temperature- underfloor heating works at ~35 deg C, radiators work at
100.
by fest 4y ago
I am currently installing a Thermia Calibra ground source heat pump (installers are apparently too busy). When I looked at the insides of the pump, the simplicity of construction was surprising- I could readily understand whats going on, as
101.
by fest 4y ago
To anyone who's wondering how is such a feat possible: it's covered in the first few chapters of Dan Raymer's Aircraft Design. Reading it made me appreciate (again) the "old" way of knowledge sharing- books and publ
102.
by fest 4y ago
There is a small minority that refuses to buy Apple products because of ideological causes (at least that is the reason for me- I am not comfortable with supporting a company that locks it's users in a walled garden).
103.
by fest 4y ago
Not in Latvia- it's an online application, you get a decision (=does the grid have generation capacity in your location), and then submit an installation report signed by electrician. Getting building permits for installations was wai
104.
by fest 4y ago
At least here, the heatpump and installer availability seems to be the biggest bottlenecks. I'm not looking forward to it, but I may end up having to install (ground source) heat pump myself (assuming it will be delivered this season a
105.
by fest 4y ago
Some politicians in Latvia are using the same rhetoric: our hydro plants have a production cost of 0.1x/MWh, but nordpool price is xMWh. Somebody is stuffing their pockets!! What they don't say is: some of our hydro plants are bei
106.
by fest 4y ago
At the current electricity prices, break even point for household PV installations even in coldish climate (Latvia, Eastern Europe) is on the order of 3-4 years without subsidies. Granted, it does not solve the problem that the energy I&#x2
107.
by fest 4y ago
It also depends on your roof material- if it's flat, couple of extrusions to support corners of the panels is less material than full length extrusions. When I shopped around for components, the prices did range from ~20-30EUR per pane
108.
by fest 4y ago
I'm using KiBot for this, see pcb_replace/sch_replace/set_text_variables options here: https://github.com/INTI-CMNB/KiBot#supported-preflight-optio...
109.
by fest 4y ago
It's still not fun, but I'd put it on par with Altium Designer: + at least I don't have to generate my own bog-standard 0402, 0603 resistor/capacitor footprints, + a lot of the standard IPC-something footprints are inclu
110.
by fest 4y ago
Yes, I think this is undervalued feature, which should be used more in professional contexts. - being able to tag a commit, which automatically updates silkscreen with tag name/board revision and commit date. - being able to run automa
111.
The tooling ecosystem that adds joy to KiCad(media.ccc.de)
156 points by fest 4y ago|93 comments
112.
by fest 4y ago
A soviet-era book on machining I recently read stated that up until that point, about 40% of the total steel and cast iron production since 1890 has been lost to corrosion.
113.
by fest 4y ago
Why don't you? 10 years ago I was getting tired of working on php crud apps, revived my electronics hobby, practiced on small contracting jobs, landed an interesting embedded software position which then lead to my current position job
114.
by fest 4y ago
Since the start of chip shortage I have been defaulting to RP2040 for my hobby/learning projects. The PIO has been useful for some applications: * 13 bit 8M baud UART receiver for Digipan x-ray sensor. Alternative would have been a sma
115.
by fest 4y ago
> In fact, for most purposes, a slot screw was enough. Enough for removing, but I dread fastening more than a couple slotted bolts at a time- the driver always slides out easily, is not self centering, and you still need several sizes to
116.
by fest 4y ago
And your systems actually support decryption and entering the said keys. You might be surprised what proportion of the hardware that operates in Ukraine (from both sides) is using civillian grade GPS receivers (i.e. almost anything with a p
117.
by fest 4y ago
The board area under CPU is usually filled with ceramic capacitors, not to mention the lack of ecosystem support (i.e. CPU vendors just cannot rely on everyone starting to provide additional cooling from the other side, so they have to desi
118.
by fest 4y ago
Generally by using the dimensions and heat conduction properties of the exterior surfaces of the house (area of foundations, walls, windows, roof), taking into account the heat gain due to sun, with some local fudge factors applied (loss du
119.
by fest 4y ago
Indeed. I just looked up the heat loss for my house: 213W/ deg K. So, to maintain 20 deg C inside with -20 deg C outside requires about 8.5kW of heat energy (200m2 single-family house built around 2008), or approx 200kWh/day.
120.
by fest 4y ago
In a climate I live in (Latvia , -20 degC for a few weeks in winter), reasonable energy consumption for heating of single-family house is around 100kWh/m2/year. My 200m2 house is slightly worse at ~120kWh/m2/year, or aro

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