From Zero to Nano

Have you ever wanted to build your own Arduino from scratch? [Pratik Makwana] shares the entire process of designing, building and flashing an Arduino Nano clone. This is not an entry-level project and requires some knowledge of soldering to succeed with such small components, but it is highly rewarding to make. Although it’s a cheap build, it’s probably cheaper to just buy a Nano. That’s not the point.

The goal here and the interesting part of the project is that you can follow the entire process of making the board. You can use the knowledge to design your own board, your own variant or even a completely different project.

from-zero-to-nano-thumb[Pratik Makwana] starts by showing how to design the circuit schematic diagram in an EDA tool (Eagle) and the corresponding PCB layout design. He then uses the toner transfer method and a laminator to imprint the circuit into the copper board for later etching and drilling. The challenging soldering process is not detailed, if you need some help soldering SMD sized components we covered some different processes before, from a toaster oven to a drag soldering process with Kapton tape.

Last but not least, the bootloader firmware. This was done using an Arduino UNO working as master and the newly created the Arduino Nano clone as target. After that you’re set to go. To run an actual sketch, just use your standard USB to UART converter to burn it and proceed as usual.

Voilá, from zero to Nano:

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The Zero Ohm Resistor

What’s your favorite value of resistor? 1K? 10K? They’re all fine, but when you need nearly no resistance at all, nothing beats the good old zero-ohm resistor.

Wait a minute! Resistors are supposed to resist current. What the heck does a zero-ohm resistor do? Well, the short story (tee-hee!) is that it’s like a jumper for single-sided surface-mount boards. In the bad old days, companies used to save money by running single-sided boards, and you could buy wire jumpers to help make the layout that much easier.

Fast forward to the modern era, where there’s not a through-hole component to be seen. What’s the resistance (ideally) of a wire? Zero ohms. And thus the zero-ohm resistor was born. We have a whole spool of them in our closet in 1206, the largest SMD size that we use, in order to be able to sneak two or three tracks underneath, even on a home-etched board. They’re great.

Anyway, what set us off rhapsodizing about the lowest value resistor was this article on the peculiarities of the zero ohm resistor. Of course, nothing has zero resistance, and the article walks you through some of their real-world properties. Enjoy!

A DIY Vacuum Pickup Tool for $75

If you’re assembling prototypes of SMD boards on your own, placing the parts accurately can be a pain. Of course, it’d be nice to have a full pick and place machine, but those are rather expensive and time consuming to set up, especially for a small run of boards. Instead, a vacuum pickup tool can help you place the parts quickly and accurately by hand.

The folks over at Ohmnilabs have put together their own DIY pickup tool for about $75, and it’s become part of their in-house prototyping process. They grew tired of placing components with tweezers, which require you to remove parts from the tape before lifting them, and have a tendency to flip parts over at the worst time.

The build consists of a couple parts that can be bought from Amazon. An electric vacuum pump does the sucking, and the vacuum level is regulated with an adjustable buck converter. A solid foot switch keeps your hands free, and syringe tips are used to pick the parts up.

This looks like a simple afternoon build, but if you’re prototyping, it could save you tons of time. To see it in action, check out the video after the break.

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Ugly Manhattan Adapters

“Ugly” or “Manhattan” style circuit building is popular among ham radio folks. Basically, you solder the circuit point-to-point, using a solid copper plate as a backplane. “Manhattan” gets its name from the little pads and parts of different heights strewn all around the board — it looks like the Manhattan skyline. It’s a great one-off construction method and actually has reasonably good properties for radio/analog circuitry. It’s easy to pull off with leaded components, but gets trick with smaller surface-mount parts.

Unless you build some adapters. [Ted Yapo] has made his library of small Manhattan adapters available for us all to use. There’s also no reason to stop with SMT parts — even normal DIP parts can be easily adapted to Manhattan construction, as this teasing photo of a bunch of [Ted]’s adapters shows. And if he doesn’t have the layout you need, the source files should give you a good starting point.

If you want to get started with Manhattan (or other “ugly”) construction, we’ve got a guide for you. And in case you take the “ugly” moniker too seriously, check out this incredibly beautiful ugly build.

Design for Hackers

Near the end of the lifecycle of mass-market commercial product development, an engineering team may come in and make a design for manufacturability (DFM) pass. The goal is to make the device easy, cheap, and reliable to build and actually improve reliability at the same time. We hackers don’t usually take this last step, because when you’re producing just a couple of any given device, it hardly makes sense. But when you release an open-source hardware design to the world, if a lot of people re-build your widget, it might be worth it to consider DFM, or at least a hardware hacker’s version of DFM.

If you want people to make their own versions of your project, make it easy and cheap for them to do so and don’t forget to also make it hackable. This isn’t the same as industrial DFM: rather than designing for 100,000s of boards to be put together by robot assembly machines, you are designing for an audience of penny-pinching hackers, each building your project only once. But thinking about how buildable your design is will still be worthwhile.

In this article, I’m going to touch on a couple of Design for Hackers (DFH) best practices. I really want to hear your experience and desires in the comments. What would you like to see in someone else’s open designs? What drives you nuts when replicating a project? What tricks do you know to make a project easily and cheaply buildable by the average hacker?

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Tools of the Trade – Inspection

In the last episode, we put our circuit boards through the reflow process. Unfortunately, it’s not 100% accurate, and there are often problems that can occur that need to be detected and fixed. That’s what the inspection step is for. One could insert an inspection step after paste, after placement, and after reflow, but the first two are icing on the cake — the phase where most mistakes can be caught is after reflow.

There are a number of problems typical with a surface mount reflow process: Continue reading “Tools of the Trade – Inspection”

Tools of the Trade – Reflow

In our previous issues in this series on making circuit boards, we covered placing solder paste and placing components. Now it’s time to bake our cake!

There are a variety of methods for reflowing a circuit board, but they all rely on a single principle: heat up the solder paste (a mixture of flux and solder) until the flux burns off and the solder becomes liquid, and then cool it down. Accomplishing this once or twice is easy; once you’ve played with a hot plate you’ll swear off through hole. Scaling it up and doing it repeatedly with high yield is extremely challenging, though. Continue reading “Tools of the Trade – Reflow”