'We thought we'd sell 1,000': The inside story of the Raspberry Pi

Maybe it's just me but it seems to me that it would be more likely that someone would get their hands on an inexpensive used monitor to tinker with instead of using the family TV. An inexpensive monitor would also allow you to set up basically anywhere in the house.

I know when I was growing up I would not have been able to tinker using the TV for very long before someone else in the family would want to use the TV.

+1 -- one of the biggest hurdles I had when I got my pi was actually connecting to the thing. I don't have a TV, and neither do any of my friends.

Eventually I just brought it in to work and plugged it into one of the TVs we use for information display for our customers.

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Since then, though, I've started work on this: http://raspihacker.com

The aim of this is to address some of the problems that I encountered with my raspi.

This is true. I've been buying $87 21" 1080p monitors with HDMI. That's pretty cost effective for a dashboard.

HDMI connector is also a darn sight smaller, which is good for limited board space, and probably cheaper than a D-SUB connector as well. (Remember, they were pretty tightly squeezed on budget)

You may even have a spare adapter buried in your closet like I did. More and more graphics cards are coming with HDMI -> DVI-D adapters, you see.

Thank you for the comment, as I did not live during the hayday of then(born in 1981 and had an electrician as a father). But regardless of what you are saying my point is still clear: Globalization and newborn tech and hacker mentality are souring; Not as much as when they started!

Of course this is all interesting. But times are very different! Radio Shack hobbyists were at the forefront. There were not SO many of them.. but because the latest chips and other doohickies were fairly expensive in today's world, allowed Radio Shack to prosper. We are both on HN, so we are a bit different than normal population... Globalization changed that, I'm in NYC, you?

Hmm...I guess my memory isn't so keen. Maybe I was thinking of another system. It was called 'cherry' something but it was under but closer to $100. But I see your point.

Incidentally that 1/10th cost is one of the reasons I want to get into designing hardware so if you have pointers on that, it'd be helpful. :)

Hell it was in the impulse buy range for me and I'm a college student! :)

I forgot about that part, I was thinking back to my experiences at a hardware startup. The battery circuitry was only a small portion of the board, but it was the most complicated electrically.

Yeah, in the simplest case you can battery power a pi with one of those rechargable battery-pack usb chargers meant for cellphones. Those require absolutely zero technical skill, start around $20, and it looks like they can power a pi from a few hours to more than 10.

The power distribution on a board is essential to it running properly. The 5v needs to go into 3.3v and probably 1.2-1.8v as well. You need to make sure that any loads on the power net won't cause a momentary voltage drop below any component's tolerance. You also want to make sure that the components on the far end of the board will receive the same voltage that everything else is receiving. Next you want to make sure that any digital chips won't inject noise on the line and have their own power reserve via decoupling caps. These capacitors need to be speced out to block specific frequencies and placed accordingly. Also, grounding is super important to consider as you want to have a stable "0V" reference (for digital only designs this means having a dedicated ground plane, mixed analog and digital can have separate ground planes).

Now, for most hobbyist designs the rule of thumb is use a simple LDO and the recommended input/output caps (1-10uF) for it and use wide traces to route the power in a star like fashion. Also put a 100nF capacitor next to each power pin for noise and to serve as a power reserve.

More complicated circuits / circuits that will need to go through FCC will require more complicated power distributions. Most professional boards (with high frequency signals on it) that will meet FCC will be 4+ layers, with a dedicated ground and power planes. A PCB I just designed with an FPGA on it had something like 50 capacitors for just the 1 chip, with physical size requirements for each type (the smallest capacitors were 1mm x 0.5mm to block the highest frequency noise, anything bigger won't be as effective).

Don't let this deter you however, looking back on my first schematic/PCB designs I'm amazed at how much better I've gotten. Microcontroller designs with a few chips are very, very lenient. If you mess something up it will likely still work, but your performance won't be as good (i.e. if you use a built in ADC it may not be as accurate, or you might not be able to reliable run it at it's max clock speed)

* How do I do board layout?

You learn an EDA tool such as Eagle, pick a board vendor, and produce a design that meets the board vendor's specifications. You submit an order, and get boards in the mail. It's like designing and getting custom t-shirts made, expect much more involved.

* How do I know which components to put on a board?

Mostly datasheets. Once you identify your subsystems (I want this micro, that USB interface, this video chip) you get the datasheets and read them to learn how to design the schematic for that part. How do you pick what micro or USB chip? I start by browsing hobbyist websites to see what is popular and digikey to see what meets my specs and is cheap.

* How do I know what components go where?

On a hobbyist board running in the kHz range? They mostly go where they fit. There are no rules, just guidelines- group things by how they connect, so you have less wire everywhere. Rats-nests are hard to design and debug, and component placement is the #1 way to fight rats-nest. Put central components (like the microcontroller) in the center. Put ports on the edge of the board. Put the USB chip next to the USB port.

* How do I test the system I want to build.

You build it. There's no simulation. You build it, and if things are wrong you figure out why with a multimeter and maybe an oscilloscope.

You can try breadboarding if you have a simple through-hole circuit. If things are SMD-only, you'll have more trouble.

While fairly basic, the Arduino boards are probably some of the most documented out there and would be a decent starting point.

Look at KiCad (open source) or Eagle (free to hobbyist) for a schematic capture / electronic design. But for a starter in hobby electronics, you might start by following a blog like "Dangerous Prototypes" or "HackADay"

"Making a schematic" is more of a thing you do in facilitation of something else, like designing a circuit (or documenting a circuit you already built, etc). You say you "know digital circuits and simple DC circuits", but it doesn't sound like you have the necessity of the design part in your head as solid as it should be. It really sounds like you're asking how to get started in electronics and build complete circuits rather than tinkering with demo boards.

I'd recommend choosing a microcontroller, probably a PIC or AVR, in a DIP package and putting it on a breadboard (or are there even ARMs in DIPs these days?). Figure out how to program the chip directly, and get it running by hooking up its supporting components (power, crystal, etc). You can rely on schematics of others' designs for the same chip. At this point you should have similar functionality (blinking LEDs, etc) as if you were using an Arduino (AFAIK Arduino, that is). It won't seem like you've accomplished much, but the whole point is to get comfortable working with raw components instead of anything "magic" (although an MCU is quite magic).

You then want to get comfortable building other kinds of independent circuits on the breadboard, probably hooking them up to the MCU so you're able to use your programming abilities as leverage. I'd recommend starting to play with opamps next (and ADCs on the MCU), but if you've got some ultimate goal in mind (and you probably will), figure out what type of chips are meant to comprise that functionality, get some in DIP packages, and start making them work using manufacturer's application notes as a starting guide.

1. Analysis, both before and after, are much more important than for software. Imagine you're working on a program that modifies its own source code, with no ability to backup.

2. There are no magic black boxes. Every component and pre-baked solution is made up of sub devices that you can be familiar with. Abstractions are there to simplify your overall thinking, but when trying to debug, you are going to be thinking about eg what the specific circuit behind the pin of a chip looks like.

3. Eventually you'll be confident enough to know what parts of the circuit you should build out before even laying out a board, and which should be relatively straight forward to blindly fab. But this only comes with knowing your experience and strengths.

4. This stuff takes a long time to get right. Good luck!

Email me, I'll be happy to walk you through the process of getting your first board made. I'm also available on IRC as Kliment on the freenode network. It's an incredibly fun thing to do if you like attention to detail, and incredibly frustrating otherwise.

Yeah. It's funny in my case, though. I'm writing a music streaming web app and not sure yet if the RPi will be able to transcode formats in real-time, so have pondered using decoders in JavaScript, e.g. [1], instead. Normally this would be an obvious task to do on the server side.

[1]: https://github.com/ofmlabs/flac.js

Um... he did post to HN... so... yeah, I guess maybe he could be doing that from the public library.

I see absolutely no evidence that the Raspberry Pi Foundation is unsavory in any way.

Yeah, I wonder how much customers they lost because of the supply problems. I was very existed on the day it started selling (or DDOS those two sites), wanted to buy two. But I wasn't able to, so I waited few weeks until I could place an order, but my interest faded with time, and as of now (almost year after they started selling it) I still don't own zero respberrypis.

I don't know why you are so insistent having an uncharitable interpretation of the article.

"The first inkling of the fervour the credit card-sized board would create came in May 2011, when the first public outing of the Pi in a BBC video generated some 600,000 views on YouTube.

Upton and his colleagues revised their initial run of boards up to 10,000, thinking that would be more than enough to meet demand."

There initial plans were to produce far less than 10k. They were surprised when they had to adjust their plans up to 10k, and surprised again to learn that their estimations were grossly inaccurate.

Also, the earliest story here about the Raspberry Pi was from 2 years ago. "Day one" for them was 5+ years ago.