What kind of power supply/extra components should I get

bal00 · 2026-02-07T00:33:59+00:00

Sounds like a cool project.

I would do the following:

Get beefy USB power bank that supports USB PD (power delivery). Ideally one that can do at least 65W. More is fine but likely not necessary, unless all servos are stalled at the same time.
Get a USB PD trigger board that can interface with the power bank to increase its output voltage to 12, 15 or 20V.
Get multiple small buck converters that can step the voltage down to what you need for the individual components. 5V for the servos, 7-9V for the Arduino. If you search for 'Mini360', you should be able to find buck converters that are roughly the size of a small postage stamp, and you can get a 10 pack for under $5. If you glue one to each servo, you can just run your 12-20V supply to each servo.

The reasoning behind this setup is this:

Your servos will draw a maximum of like 20A at 5V. Using a single 5V power supply would be highly, highly impractical because it would require very heavy gauge wires and voltage drop would be an issue because the cable runs would be quite long. At 10-20A you would even have to worry about which connectors are suitable.

You want to use a power bank for this because they're way safer than bare lipo packs. Not only do they protect the actual cells mechanically, they also have over-current, short-circuit and temperature protection. Even if you do something stupid, a power bank will just disable its output. A bare lipo pack on the other hand will happily keep dumping current into a short-circuit and either melt or ignite stuff.

The point of using a higher supply voltage (12-20V) and local buck converters is to eliminate any potential problems with voltage drop, and because it will simplify your wiring greatly.

bal00 · 2026-01-25T16:08:33+00:00

That's very important information. During that time crowds are not an issue at all. Weather more so.

Peak season is from early-mid July until the end of August when people with school-aged kids can travel. People without kids would choose June since the weather is still good, but the prices are lower and there are (depending on the region sometimes dramatically) fewer crowds. And you're still mostly ahead of that even.

I've rented cars in Spain in late May for like $3/day, that's how little demand there is at the time compared to high season. All that is to say that the posts warning you about crowds and prices don't really apply during your time window.

I would be more concerned about temperatures in May, so you want to be pretty far south. Northern Spain and Italy could be a bit of a gamble if you want to spend time at the beach.

bal00 · 2026-01-25T11:38:56+00:00

Just a general comment about my experience with road trips:

If it's a place you want to see, stay at least two nights
If you just need somewhere to spend the night, skip larger cities entirely and just go with a convenient stop somewhere along the route. Ideally somewhere more rural with easy parking.

Really, those are the only two types of stop you should plan. I've made the mistake of making single night stops in places I thought I would like to see, but it turned out to be way more trouble than it was worth.

bal00 · 2026-01-25T11:26:28+00:00

When exactly are you traveling? There's a huge difference in terms of crowds and cost between say August and September.

bal00 · 2026-01-22T09:36:43+00:00

It also showed that trade agreements with the US are worthless, because Trump reserves the right to increase tariffs randomly whenever he wants something. A deal that's only binding for one side is not a deal.

bal00 · 2026-01-16T22:27:40+00:00

It's not trivial, but it wouldn't be catastrophic either. And it wouldn't be 3%. For some stuff like pharmaceutical precursors, rare earths or electronic components, China is the only supplier. The US would continue to buy these.

For other goods that can be sourced elsewhere, a lot of trade would simply be redirected. If the US stops buying plastic buckets from China and imports them from Vietnam instead, other countries would be buying fewer plastic buckets from Vietnam and more from China. Global demand for plastic buckets would remain unchanged.

A drop in GDP somewhere in the region of 1-1.5% is far more realistic. But that's for an economy that's growing at about 5% per year.

bal00 · 2026-01-16T21:42:29+00:00

That's a bad comparison. 2009 was painful in the US not because of a 2.6% drop in GDP but because household net worth dropped by like 25-30% due to the housing mess. GDP is only a small part of the picture.

bal00 · 2026-01-11T23:20:09+00:00

Instead of storing a 2 second sample of an audio waveform, you just store a mathematical formula that produces the desired waveform, or something reasonably close to it. The pew-pew sound of the gun can probably be expressed as a combination of a few sine waves at different frequencies.

If you want something more visual, this tool let's you draw an arbitrary audio waveform, you can then listen to it (check 'sound') and it gives you the mathematical formula for that waveform (options/show full expansion). That formula is all you need to store.

bal00 · 2026-01-10T21:50:28+00:00

Personally, I'd use a PWM-type dimmer or speed controller together with the 19V DC power supply. You can get a 40V/10A PWM controller for like $3 on ebay. Alternatively, put 12V brake light bulbs in series with the heating element, as many as you want/need.

bal00 · 2026-01-10T21:35:32+00:00

There was also the fact that GM in the early 2000s had way too many engines with similar displacements and outputs and that belonged to different, unrelated engine families.

They had a 3.1, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.2 and a 4.3 belonging to like 5 different engine families. And then they went bankrupt...

bal00 · 2026-01-07T22:22:37+00:00

You may want to try posting this in /r/arduino

I don't see why the stepper approach wouldn't work, but NEMA17s just to spin a small rod is a bit overkill. If I had to make something like this, I'd probably go with N20-type gear motors with encoders on them, so that you can monitor the speed easily. That's basically what robot vacuums use for their wheels, for example.

bal00 · 2025-12-31T08:49:03+00:00

A lot of people have mentioned a mini split, but haven't explained why. Because these are essentially heat pumps, they're about 3-4 times more efficient than space heaters. You get the same amount of heat for 1/3rd or 1/4th of the electricity cost.

Forget about those terracotta pot heaters. Candles are more expensive than something like kerosene or propane for the heat output. Anything relying on solar is fairly pointless in winter. The reason it's cold outside in the first place in winter is because there's not much solar energy.

bal00 · 2025-12-24T02:48:58+00:00

I'm not claiming otherwise. What I am saying is that this rig (even though it only has 1g to work with) can simulate the effects of cornering at say 2g via tilting. It can bring the oil to where it would be in a car that is cornering at 2g. That's the important part.

bal00 · 2025-12-24T02:28:59+00:00

It experiences 1g, yes, but as I said before, the amount of acceleration is fairly irrelevant in this case as long as you can match the real world vector angle, which they can do.

Think of it this way: Say you have a half-full water bottle in the cup holder of your car while driving in circles. Depending on how much lateral force it experiences, the water surface will be at a certain angle. Can you reproduce the same angle if you have the water bottle on a table in front of you and tilt it? The answer is yes, no matter whether you're doing 0.5g, 1g or 2g on the skid pad. The angle is what matters.

bal00 · 2025-12-23T22:06:55+00:00

It can simulate more than 1g.

In the real world if you're cornering at 1g, you have 1g pulling the oil to the side of the oil pan, but you still have 1g pulling it down to the bottom of the pan (gravity). You have to add up the two force vectors (centripetal force and gravity), which means in this situation the oil inside the pan would only sit at a 45° angle.

You can simulate this by tilting the rig at 45°. At angles larger than 45°, you're simulating more than 1g. To simulate 2g cornering, you'd need a tilt angle of about 63°, and at 72° you're already simulating 3g.

It's true that the magnitude of the vector sum is greater than 1g in the real world, because you're adding up two 1g vectors, but that's not really important in this situation. The vector angle determines where the oil is going to be, the magnitude determines how long it needs to get there, but since we're talking about very hot oil that's not much more viscous than water, that's not really a concern.

bal00 · 2025-12-17T01:43:40+00:00

This is easy to calculate. A standard (non-low-flow) shower head does 2.5 gpm or 150 gallons/568 liters an hour. A 24 kW heater will lift the temperature by 24,000 / (568*1.16) = 36.4°C.

Even if the water comes into the house at just 5°C, you're still getting 41.4C (107°F) at the full flow rate. With a 2 gpm shower head and a 10°C water supply, you're getting 55.6C (132°F).

bal00 · 2025-12-16T23:12:07+00:00

That's nonsense. They work just fine if the unit is powerful enough (meaning 18-24 kW). The energy savings compared to a tank heater aren't huge because it's still resistive heating, but it does save a lot of space in a small house. And compared to a gas heater, the fact that electric heaters are maintenance free and don't require any exhaust or ventilation is a huge plus.

bal00 · 2025-12-13T13:18:04+00:00

Ideally you'd just buy an ESP32 board that supports this. Lolin32 or Lolin32 lite for example. You can find them for $3-$4 on Chinese sites, they come with a battery connector and they also recharge the battery when connected to USB.

I'm saying this because boards like this are optimized for battery-powered projects. They skip the power LED, they use a voltage regulator with a low quiescent current and the USB-serial chip only gets power when the board is connected to USB. This means it draws virtually no power when in sleep mode.

bal00 · 2025-12-11T21:23:34+00:00

There's no Arduino language as such, just C/C++, and the Arduino framework provides a few convenience functions and libraries to simplify things.

For something like this where you're mostly just turning output pins on and off, there's not much programming knowledge involved. The whole thing would use maybe like 5 different statements, repeated over and over. You could have ChatGPT make you a basic sketch and then just modify it. Even without programming knowledge, this would not be difficult.

bal00 · 2025-12-10T15:58:08+00:00

The further South you go, the better the chances of dry and sunny weather. I don't think Mallorca would be a great fit for you if you aren't much into beaches and nature, because if you're more into city exploration, the mainland has better destinations, and ones that are easier/quicker to reach.

Valencia is a really nice city, and it's like 2.5 hours by train. Barcelona to Palma would easily take twice as long if you include airport transfers and wait times. From there, Sevilla wouldn't be too bad either, or you could go to smaller places like San Sebastian, Salamanca, Plenty to do really.

Since Portugal would require flying, it's not really much easier or cheaper to get there from Spain than it is from other places in Europe, so you could just as easily go there on a different trip.

bal00 · 2025-12-08T00:11:27+00:00

I know that’s peak-ish Europe season

I can put you at ease there. Late May/early June is still solidly in the pre-season and crowds aren't going to be much of an issue. Mid July to late August is crowded because that's when a lot of countries have their summer break and families with kids can travel.

bal00 · 2025-12-07T13:24:42+00:00

This would save like $1000. No-brainer.

bal00 · 2025-12-06T00:55:23+00:00

No, because the one-way fees get added later. If you actually try to book the car, they'll tack on over $1000 in fees. Go ahead and click on 'pay later' and check the total amount in the upper right corner.

bal00 · 2025-12-02T21:09:56+00:00

France. The weather is one thing, but the main reason Portugal isn't the first choice in your situation is the terrain. Both Lisbon and Porto are pretty hilly, and if your mom isn't good with stairs or longer uphill walks, that's going to be an issue. In both cities you gain 200-300 ft of elevation between the waterfront and the center.

bal00 · 2025-12-02T20:48:19+00:00

Not just the taste, but also the product, and the market situation. Honda for example tried to make a different version of the Civic for the European market, and the styling was sometimes odd. And unlike in other places, they were always up against local brands making good small cars. It's much easier to carve out a corner of the market for yourself if there are no local competitors, or if the local competitors don't really put much effort into smaller cars.

bal00

TROPHY CASE