https://lemmy.world/post/22892985

/c/technology was the most active by far (more so than /c/cars), so I'll post here again first.

Stats

The following stats are winter tests (10F to 30F. Or -10C to 0C).

• L1 Charger from Home is 2.05 mi/kwhr (12.0 mi/electric-$$. 17.1c per kwhr home costs) in this deep cold.

• L2 Charger from Work is 2.8mi/kwhr (14.0 mi/electric-$$. 20c per kwhr work-charging costs).

• 43 Miles per Gallon gasoline (13.9 mi/gasoline-$. $3.10 gasoline during test).

• L1 Charger is closer to 2.8 mi/kwhr during 60F (15C+ temperatures).

• L2 Charger is closer to 3.5 mi/kwhr during 60F (15C+ temperatures).

Conclusion: The cold (10F to 30F) has made the Li-ion batteries of this car SIGNIFICANTLY less efficient. We're at the point where L1 chargers are more expensive than gasoline, while L2 chargers are roughly on part with gasoline.

I recommend anyone who gets an EV to get an L2 charger. Not only for the convenience of far faster charges, but also because of the incredible improvements to cold-weather charging efficiency.

There were some pro-EV fans asking me to more carefully test the gasoline usage in the winter. And now you have the stats. I can solidly say that gasoline is worse during the Winter (down from EPA estimated 48), but not dramatically worse like the electric engine gets.

The above gasoline test was done over an entire week of driving to reach the 200+ miles I thought was needed for a solid test. I performed it by running out of electricity (all the way down to 0%), then driving to a gasoline station and filling up. I memorized the exact pump I filled up at.

Then, after 200 miles across a week, I came back to the same pump and filled up exactly the same. I then counted the gallons that came out of the pump and divided out based on my trip odometer. I was 203.5 miles of driving total with 4.734 gallons reported from the pump.

cross-posted from: https://lemmy.world/post/22892955

The Prius Prime is a dual fuel vehicle, able to run 100% on Electric, or 100% on gasoline, or a computerized blend in-between. This presents me a great opportunity to be able to do a direct comparison with the same car of an EV engine vs an ICE engine.

• Toyota computer claims 3.2mi-per-kwhr.

• Kill-a-watt (https://en.wikipedia.org/wiki/Kill_A_Watt) claims 2.2mi-per-kwhr.

• Additional 1.5% losses should be assumed in the wires if you wish. (120V drops down to 118V during charging, meaning 2V of the energy was lost due to the resistance of my home's wires).

• Level 1 charger at home (known to be less efficient).

• Toyota computer claims 53miles-per-gallon (American Gallon).

• I have not independently verified the gallon usage of my car.

• 295 miles driven total, sometimes EV, sometimes Gasoline, sometimes both.

• 30F to 40F (-1C to 4.5C) in my area this past week.

• Winter-blend fuel.

• 12.5miles per $electricity-dollar (17.1c / kw-hr home charging costs)

• 17.1 miles per $gasoline-dollar ($3.10 per gallon last fillup).

If anyone has questions about my tests. The main takeaway is that L1 charging is so low in efficiency that gasoline in my area is cheaper than electricity. Obviously the price of gasoline and electricity varies significantly area-to-area, so feel free to use my numbers to calculate / simulate the costs in your area.

There is also substantial losses of efficiency due to cold weather, that is well acknowledged by the EV community. The Prius Prime (and most other EVs) will turn on a heater to keep the battery conditioned in the winter, spending precious electricity on battery-conditioning rather than miles. Gasoline engines do not have this problem and remain as efficient in the winter.

I originally wrote this post for /c/cars, but I feel like EVs come up often enough here on /c/technology that maybe you all would be interested in my tests as well.

The Prius Prime is a dual fuel vehicle, able to run 100% on Electric, or 100% on gasoline, or a computerized blend in-between. This presents me a great opportunity to be able to do a direct comparison with the same car of an EV engine vs an ICE engine.

• Toyota computer claims 3.2mi-per-kwhr.

• Kill-a-watt (https://en.wikipedia.org/wiki/Kill_A_Watt) claims 2.2mi-per-kwhr.

• Additional 1.5% losses should be assumed in the wires if you wish. (120V drops down to 118V during charging, meaning 2V of the energy was lost due to the resistance of my home's wires).

• Level 1 charger at home (known to be less efficient).

• Toyota computer claims 53miles-per-gallon (American Gallon).

• I have not independently verified the gallon usage of my car.

• 295 miles driven total, sometimes EV, sometimes Gasoline, sometimes both.

• 30F to 40F (-1C to 4.5C) in my area this past week.

• Winter-blend fuel.

• 12.5miles per $electricity-dollar (17.1c / kw-hr home charging costs)

• 17.1 miles per $gasoline-dollar ($3.10 per gallon last fillup).

If anyone has questions about my tests. The main takeaway is that L1 charging is so low in efficiency that gasoline in my area is cheaper than electricity. Obviously the price of gasoline and electricity varies significantly area-to-area, so feel free to use my numbers to calculate / simulate the costs in your area.

There is also substantial losses of efficiency due to cold weather, that is well acknowledged by the EV community. The Prius Prime (and most other EVs) will turn on a heater to keep the battery conditioned in the winter, spending precious electricity on battery-conditioning rather than miles. Gasoline engines do not have this problem and remain as efficient in the winter.

Hey, lots of Political Topics coming up that's just turning into blame games, anger and bad vibes. I'm enacting a temporary rule: no new politic topics for one week as of now.

I recognize that there is a lot of anger around the election and it's legitimate to feel that way. But I'm willing to bet that none of the political talk in the next week constitutes a 'Best Of' post anyway.

That being said: feel free to use this topic (!!!!) as political talking points. I'm serious. People deserve to discuss their opinions and I don't want to hamper them too much.

If you have political stuff to say, say it in here. I'll promise to lightly moderate this topic, which means this topic will naturally lead to bad vibes and poor arguments.

But we need a place to discuss and vent.

Hey Gaza / Free Palestine guys,

I'm pissed about the Kamala loss but that's not important right now. I need to know what media you were using.

Where did Free Palestine/ Gaza memes and discussions start?

I'm worried that the discussion is a right wing disinformation campaign designed to make us tear each other apart. I cannot find any legitimate politician (even far left ones like Bernie Sanders, AOC, etc. etc) that would have pushed the message of 'Joe Biden / Kamala is just as bad as Trump on the issue of Gaza'.

The only ones who would push that message are right wing trolls who try to separate us. So now I want to track down and confirm my suspicions. Who meme'd this? Where did you hear it? Was it Twitter? TikTok? Reddit? Facebook? Instagram?

Despite all the doom scrolling, Harris has a comfortable lead in the electoral college right now.

The time for vibing is over. It's too late to change anyone's opinions (especially because national level events like debates are over). Harris will finish her Media Blitz soon (including a Fox News showing) while Trump retreats into his shell hoping no one notices how damn stupid his mouth is.

This is the time for doing. The focus should be on voter drives and other get out the vote pushes. It's mid October, and the October surprises are against Trump and in our favor.

It's not the lead we wanted but it's a lead nonetheless. Don't talk yourself out of believing this lead because of a bad poll or two.

Just working on my recent electronics project and I needed two temperature sensors for it. This time around I didn't feel like making a full PCB from KiCAD and wanted to keep things simple with a 1/2 size solderable breadboard.

As usual, I'm using an AVR DD (this time: a curiosity nano devboard) for simplicity. (I expect to need the 32768 Hz clock crystal, so a PCB with said clock would be nice. Otherwise, the DIP package is available). The overall circuit is pretty simple, but the topic of discussion today is the MCP970X series temperature sensor.

https://www.microchip.com/en-us/product/mcp9701a

At this point I do recommend people to read the documentation.

The gist is that you simply apply 3.1V to 5.5V between Vdd and Gnd. Vout will have some amount of startup time, and eventually output 400mV + (Temperature-in-C * 19.5mV). For example, my room temperature is ~24C right now and the voltage output is ~920mV.

(There's clearly errors in my ADC but I'm saving that for later... this device is supposed to be outputting 876mV given the room's temperature)

With a ~6uA expected current, this device is power-efficient enough to run from most MCU pins. AVR DD's 50mA-per-pin is overkill, but more importantly, a through-hole design like mine seemingly has substantial inductance on all wires.

The datasheets claim a startup time of 0.8ms. Alas, when I soldered on the MCP9701 and turned on the GPIO-pin, it took over 20ms (!!!) before the oscillating signal finally calmed down and settled upon the room temperature reading.

To counteract this parasitic inductance, I've added a 10kOhm resistor and a 10nF capacitor out of my through-hole kit. (E12 resistor kit and E6 capacitor kit). With 220us of startup time now on the GPIO pin and with only 500uA max current going to Vdd... there is no more "ringing" anymore and life is good!

EDIT: I should probably note that my goal was to return to 0.8ms startup time, like the documents suggest. 10kOhm was chosen as 500uA (5V) to 250uA (after charging to 2.5V) is a magnitude more current than I need and is a decent starting point. 10nF was chosen to pair-up with this to give me startup time in the 100us range but not over 800us (I don't want to be "slowed down" by the charging capacitor, so I want the Vdd charge to be faster than 800us claimed startup time). It should be noted that a 5V over 1000us curve was claimed as a 800us startup in the MCP970x documents if you read all the graphs.

Moving forward, my last task is that of calibration. The on-board ADC of the AVR DD is apparently quite accurate, but the Vref of the microcontroller is +/-4% (!!). With a +/- 2% accuracy of the temperature sensor, there is some calibration I should do.

The ADC errors + Vref errors are expected to just be linear. The temperature-sensor's error is quadratic however. In both cases, I don't want to overcomplicate things, so I'm planning on just adding a constant-offset to the mV reading to shift it to the correct spot.

All in all: pretty standard Analog-to-digital conversion issues here. But I figured it'd be a good discussion topic for beginners.

Modern AVR has a wide variety of Timers (TCA, TCB most commonly, but TCD, TCE, and TCF are uncommon and specific to particular AVR chips).

This can make choosing a AVR DD vs AVR EA vs AVR EB vs AVR DA a difficult choice, especially if you're trying to use timers to their greatest extent possible.

This blogpost covers a basic idea of what the different timers offer.

The blogpost is short enough. I feel like what I can add is to highlight the difference between:

• Timers -- A background count++, a comparator of count vs some pre-configured values, and then likely an output pin that changes based off of these configurations. Consider this an MCU output. Almost everything listed can be used as a timer.

• Counters -- Counter functionality is an MCU input. Many protocols, such as Servos, PWM, pulse-train decoding requires a variety of pulse-frequency-modulation, pulse-counting, or wide variety of other kinds of common tasks. "TCB" may be called a "Timer", but its really more of a counter-focused device which can more easily measure frequencies (for pulse-frequency-modulation). TCA and a few others can do some basic counting tasks, but usually not as well as TCB.

The other discussions in the blog are easy enough to understand IMO. This is all AVR specific, but some of the best material online are highly specialized articles like this, so I still feel like sharing.

1.5 c Microcontroller alert.

Very low-end, but 38kHz support is explicitly called out in its product manual. This means that this tiny uC is ideal for TV remote control (or other IR-blasters).

I wouldn't recommend anyone use this chip unless you were some kind of professional saving pennies. Typical $1 uCs are far easier to work with and have exponentially more power (even $1 8-bit uCs). Still, its an interesting thought experiment for what a 1.5 cent uC could be used to implement....

This blogger booted an F1C100s from scratch, even though they made a mistake buying 16MBit instead of 16MByte of Flash. (Requiring to be booted off of USB-bootloader / Allwinner's FEL Protocol instead of Flash).

So a few mistakes were made, but its still a custom booting Linux + blogpost that explains the steps.

What really interests me about this design is the ~~buck~~ Boost-converter

So this ~~buck~~ boost-converter is 100% core-independent. The Analog Comparator, TimerD, CCL, and Event-System are all active while the AVR DB sleeps, meaning that the microcontroller can run this simple ~~buck~~ boost-converter without any cost to CPU time.

An incredible design that demonstrates the flexibility of AVR DB's combined peripherals.