Circuit VR: The Dickson Charge Pump

There was a time when taking a low DC voltage — say a single battery — and converting it to a higher voltage was painful. Now, however, cheap and easy-to-use DC to DC converters are readily available. For some small tasks, though, these can seem like overkill. For example, consider a case where you need to supply a higher voltage for a MOSFET gate that doesn’t draw much current. Perhaps you need that higher voltage to trigger a microcontroller’s programming mode and nothing else. The current draw is minimal, and a full-blown DC to DC converter is overkill. For cases like that, it is tempting to use some voltage multiplication scheme. There are many, but for this post, I’m going to take you inside a Dickson charge pump. This is Circuit VR because not only are we going to discuss the circuit, we’ll look at an LT Spice simulation you can try yourself.

The Dickson is interesting because it doesn’t require any AC conversion or transformers. Instead, it uses diodes or other switching elements to transfer charge between capacitors in stages. Each stage will effectively increase the voltage by the supply voltage — in theory. Reality isn’t so kind, though, as we’ll see.

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Mechanisms: Couplings

I was splitting wood one day a few years back, getting next winter’s firewood ready on my hydraulic splitter. It normally handled my ash and oak with ease, but I had a particularly gnarly piece of birch queued up, and the splitter was struggling. The 20-ton cylinder slowed as the wedge jammed in the twisted grain, the engine started to bog down, then BANG! I jumped back as something gave way and the engine revved out of control; I figured a hydraulic hose gave out. Whatever it was, I was done for the day.

I later discovered that a coupler between the engine shaft and the hydraulic pump failed dramatically. It was an easy fix once I ordered the right part, and I’ve since learned to keep extras in stock. Couplings are useful things, and they’re the next up in our series on mechanisms.

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The Basics And Pitfalls Of Pointers In C

Pointers — you either love them, or you haven’t fully understood them yet. But before you storm off to the comment section now, pointers are indeed a polarizing subject and are both C’s biggest strength, and its major source of problems. With great power comes great responsibility. The internet and libraries are full of tutorials and books telling about pointers, and you can randomly pick pretty much any one of them and you’ll be good to go. However, while the basic principles of pointers are rather simple in theory, it can be challenging to fully wrap your head around their purpose and exploit their true potential.

So if you’ve always been a little fuzzy on pointers, read on for some real-world scenarios of where and how pointers are used. The first part starts with regular pointers, their basics and common pitfalls, and some general and microcontroller specific examples.

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Bringing Fiction To Life With 3D Printing

I print something nearly every day, and over the last few years, I’ve created hundreds of practical items. Parts to repair my car, specialized tools, scientific instruments, the list goes on and on. It’s very difficult for me to imagine going back to a time where I didn’t have the ability to rapidly create and replicate physical objects at home. I can say with complete honesty that it has been an absolutely life-changing technology for me, personally.

But to everyone else in my life, my friends and family, 3D printers are magical boxes which can produce gadgets, weapons, and characters from their favorite games and movies. Nobody wants to see the parts I made to get my girlfriend’s 1980’s Honda back on the road before she had to go to work in the morning, they want to see the Minecraft block I made for my daughter. I can’t get anyone interested in a device I made to detect the algal density of a sample of water, but they all want me to run off a set of the stones from The Fifth Element for them.

As I recently finished just such a project, a 3D printed limpet mine from Battlefield 1, I thought I would share some thoughts on the best practices for turning fiction into non-fiction.

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Hackaday Links: Some Sort Of Fool’s Day, 2018

A few years ago, writing for a blog called Motherboard of all things, [Emanuel Maiberg] wrote PC Gaming Is Still Way Too Hard. The premise is that custom building a gaming PC is too hard, because you have to source components and comparison shop. Again, this was written for Motherboard. Personally, I would have shopped that story around a bit more. Now, the same author is back again, telling us PC Building Simulator is way more fun than building a real computer. It’s my early nomination for worst tech article of the year.

Speaking of motherboards, This is a GoFundMe project to re-create the Amiga 4000 mainboard, with schematics. Building PCs is too hard, but the Amiga architecture is elegant. Some of these boards are dying due to electrolytic capacitor and battery leakage. This project is aiming to deconstruct an original A4000 board and turn it into Gerbers and schematics, allowing new boards to be manufactured. Building a PC is way too hard, but with this GoFundMe, you won’t have to design an entire system from scratch. Don’t worry, I already tipped off the Motherboard editors to this one.

Alright, story time. In 6th grade science class, the teacher was awesome. On the days when there was really no chance of any learning happening (the day before Christmas break, the last day of school), the teacher broke out the Electric Chicken. What’s an Electric Chicken? It’s a test tube rack, two wires, and a Wimshurst generator. “Here, grab ahold of this for as long as you can.” It got even cooler when you get a bunch of kids to hold hands and tell them pride is better than pain. Here’s a Kickstarter for a mini Wimshurst generator. It’s made out of PCBs! Hat tip to [WestfW] for finding this one.

It’s no secret that I get a lot of dumb press releases. Most of these are relegated to the circular file folder. It’s also no secret I get a lot of ICO announcements hitting my email. These, also, are trashed. I recently received a press release for an ICO that goes beyond anything else. ONSTELLAR is a blockchain-powered social media network for paranormal and metaphysical enthusiasts.  It’s the crypto for Coast to Coast AM listeners, UFO enthusiasts, and people who think PKE meters are real. This is it, we’ve reached peak crypto.

If you want to decapsulate an IC — and why wouldn’t you? — the usual way of doing things involves dropping acid, ego death, toxic chemicals, and a fume hood. There is another way. Here’s [A Menadue] decapping a quartz watch IC with just fire. The process is about as ‘hold my beer’ as you would expect. Just take a small butane torch, heat up a chip, and recover the die. A bit of ultrasonic cleaning later and you get a pretty clean chip. Microscope not included.

Fail Of The Week: How Not To Build Your Own DGPS Base Station

GPS is the modern answer to the ancient question about one’s place in the world yet it has its limitations. It depends on the time of flight of radio signals emitted by satellites twenty thousand kilometers above you. Like any system involving large distances and high velocities, this is bound to offer some challenges to precise measurements which result in a limit to achievable accuracy. In other words: The fact that GPS locations tend to be off by a few meters is rooted in the underlying principle of operation.

Today’s level of precision was virtually unattainable just decades ago, and we’re getting that precision with a handheld device in mere seconds. Incredible! Yet the goal posts continue to move and people are working to get rid of the remaining error. The solution is called Differential GPS or ‘DGPS’ and its concept looks surprisingly simple.

What’s fascinating is that you can use one GPS to precisely measure the error of another GPS. This is because the inherent error of a GPS fix is known to be locally constant. Two receivers next to each other pick up signals that have been affected in the same way and thus can be expected to calculate identical wrong positions. This holds true for distances up to several kilometers between individual receivers. So in order to remove the error, all you need is a GPS receiver in a known location to measure the current deviation and a way to transmit correction information to other units. DGPS does just that, using either terrestrial radio in some regions and satellites in others. Mobile solutions exist as well.

So a raspi with a USB GPS dongle in a known location should be able to act as a DGPS over IP base station, right? In theory, yes. In practice… fail.

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Ask Hackaday: Is Your Clock Tied To Mains Frequency?

Earlier in March we heard about a quirk of the interconnected continental European electricity grid which caused clocks to lose about six minutes so far this year. This was due to a slight dip in the mains frequency. That dip didn’t put anything out of commission, but clocks that are designed to accumulate the total zero-crossings of the power grid frequency of 50 Hz don’t keep accurate time when that frequency is, say 49.985 Hz for an extended period of time.

An interesting set of conversations popped up from that topic. There were several claims that modern alarm clocks, and most devices connected to mains, no longer get their clock timing from mains frequency. I’ve looked into this a bit which I’ll go into below. But what we really want to know is: are your alarm clocks and other devices keeping time with the grid or with something else?

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