RF Biscuit Is A Versatile Filter Prototyping Board

As anyone who is a veteran of many RF projects will tell you, long component leads can be your undoing. Extra stray capacitances, inductances, and couplings can change the properties of your design to the point at which it becomes unfit for purpose, and something of a black art has evolved in the skill of reducing these effects.

RF Biscuit is [Georg Ottinger]’s attempt to simplify some of the challenges facing the RF hacker. It’s a small PCB with a set of footprints that can be used to make a wide range of surface-mount filters, attenuators, dummy loads, and other RF networks with a minimum of stray effects. Provision has been made for a screening can, and the board uses edge-launched SMA connectors. So far he’s demonstrated it with a bandpass filter and a dummy load, but he suggests it should also be suitable for amplifiers using RF gain blocks.

Best of all, the board is open source hardware, and as well as his project blog he’s made the KiCad files available on GitHub for everyone.

It’s a tough challenge, to produce a universal board for multiple projects with very demanding layout requirements such as those you’d find in the RF field. We’re anxious to see whether the results back up the promise, and whether the idea catches on.

This appears to be the first RF network prototyping board we’ve featured here at Hackaday. We’ve featured crystal filters before, and dummy loads though, but nothing that brings them all together. What would you build on your RF Biscuit?

ESP-Micro is a Tiny Development Board

The ESP-8266 packs a lot of networking power into a small package. Some would say too small, which is why they often come on a slightly larger carrier PCB. The PCB is usually little more than a breakout with an optional 3.3V regulator. [Frazer Barnes] went one step further: he put an equally tiny USB to serial bridge, an oscillator, and some power management on an ESP-8266 breakout board.

You can program the ESP-8266 via the serial port, so having a built-in USB port is handy. Of course, you might not need it in the final product, but with the board being 25x30mm, you can probably cram it into most projects. [Frazer] posted a bit about the project on Hackaday.io, and has a GitHub project, although right now the upload of the design files is pending.

There’s no shortage of ESP-8266 projects. We saw a small Zigbee to ESP8266 board last year, and also the antidote for a tiny carrier board that includes an LCD, switches, and more. We also have tons of breakouts on Hackaday.io: here’s one with all the bells and whistles, and a similar, stripped-down version. All open-everything, and ready to go.

A Raspberry Pi Tidy Tide Tracker Predicts Propitious Promenades

The whims of the tides can make walking near the ocean a less than pleasant experience. A beautiful seascape one day may appear as a dismal, mucky, tidal flat the next. Frustrated over these weary walks, [Average Man] created a tidy tide tracker to predict propitious promenade periods.

A Raspberry Pi A+ pulls tide timing information off the web by scraping a web page using Python code. The time for the high tide, when the estuary will be full of water, is shown on a 4-digit 7-seg display. It’s all sandwiched between two smoked black panels to provide a neat case while still letting the LEDs show through.

The code comes from two projects [Average] recalled from a kickstarter timing project and a 7-seg display project. As he points out:

It’s great to learn programming from others, but it’s even better if you learn them well enough to remember, re-use and combine that code later on as well.

The display chips are mounted on a product of his own, the no longer available ProtoPal board. This is a Pi A+ size board with 288 prototyping holes and the standard connector for mounting on the Pi GPIO header. It keeps the project neat and clean.

ARMing a Breadboard — Everyone Should Program an ARM

I’m always a little surprised that we don’t see more ARM-based projects. Of course, we do see some, but the volume isn’t what I’d expect given that low-level ARM chips are cheap, capable, low power, and readily available. Having a 32-bit processor with lots of memory running at 40 or 50 MIPS is a game changer compared to, say, a traditional Arduino (and, yes, the Arduino Due and Zero are ARM-based, so you can still stay with Arduino, if that’s what you want).

A few things might inhibit an Arduino, AVR, or PIC user from making the leap. For one thing, most ARM chips use 3.3V I/O instead of the traditional 5V levels (there are exceptions, like the Kinetis E). There was a time when the toolchain was difficult to set up, although this is largely not a problem anymore. But perhaps the largest hurdle is that most of the chips are surface mount devices.

Of course, builders today are getting pretty used to surface mount devices and you can also get evaluation boards pretty cheaply, too. But in some situations–for example, in classrooms–it is very attractive to have a chip that is directly mountable on a common breadboard. Even if you don’t mind using a development board, you may want to use the IC directly in a final version of a project and some people still prefer working with through hole components.

The 28 Pin Solution

One solution that addresses most, if not all, of these concerns is the LPC1114FN28 processor. Unlike most other ARM processors, this one comes in a 28 pin DIP package and works great on a breadboard. It does require 3.3V, but it is 5V tolerant on digital inputs (and, of course, a 3.3V output is usually fine for driving a 5V input). The chip will work with mbed or other ARM tools and after prototyping, you can always move to a surface mount device for production, if you like. Even if you are buying just one, you should be able to find the device for under $6.

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Why are You Still Making PCBs?

Few things have had the impact on electronics that printed circuit boards (PCBs) have had. Cheap consumer electronics would not be as cheap if someone still had to wire everything (although by now we’d be seeing wiring robots, I’m sure). Between removing the human from the wiring process and providing many excellent electrical properties (at least, on a well-designed board), it isn’t surprising that even the cheapest examples of electronics now use PCBs.

For many years, the hallmark of being a big-time electronic hacker was the ability to make your own PCBs. There have been many ways that people have tried to bring PCB manufacturing into the hacker’s garage: stick on decals, light-sensitive blank PCBs, and even using laser printer toner (that last one spurred me to write a book on PCB layout many years back). You also see a lot of people using 3D printers or CNC mills to create PCBs. Hardly a week goes by that someone doesn’t ask me how to make a PCB in a home or small business lab.

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Organize That Messy Prototype

You’re working away busily at your project. A pcb here cabled to a breadboard in the middle, and over there some motors and other devices. It should work but it doesn’t. Time to hook-up the multimeter but the test point is on the other side. As things are moved around to reach the point, the magic smoke escapes from a critical component. Should have put those pliers away.

Workbenches are always messy. [Ryan Clark] may have an idea that can help.  His Jigmod system — currently running a kickstarter campaign — uses an acrylic a polycarbonate sheet with a grid of mounting holes to keep prototyping hardware in place. If you need to move the prototype around there is no strain on the wiring and no way to set a circuit down on that pair of pliers. The positioning of everything is your decision.

[Ryan] is also providing breakout type boards for connectors like USB and Ethernet, switches, battery holders, and other typical components. This is one place where the system really shines. A lot of these interface connectors tend to be breadboard-unfriendly and the terminal blocks these modules offer solves those issues. When you need to demonstrate your project it’s easy to transport since everything is attached to the plate. No more disconnecting cables, especially jumper wires, and hoping you get them all hooked back the right way at the destination.

With so many dev boards out there we really enjoy seeing jigs that can hold them along with a breadboard. This Stickvise-inspired 3D printed jig sticks out in our minds as a favorite. Do you have your own system of organizing your prototype builds? We’d love to hear about it in the comments!

Lessons From The Fablab Masters

I spent some time recently at the Fab11 conference, a gathering of the people behind the Fab Labs that are springing up all over the world, where entrepreneurs, hackers and the curious can learn about making things. So, it was no surprise that this was a great place to pick up some tips on designing, building and hacking things. Here are a few of the lessons I picked up at this fascinating gathering of the fabbers.

Build Quickly

If you can make something in an hour, you’ll make it better in a day

said [Joris Van Tubergen]. He knows something about making unusual things because he 3D printed a full-sized Elephant. To do this, he worked out how to hack the Ultimaker 2 3D printer to print to an unlimited Z height by flipping the printer upside down and moving the Z motor to lift the printer rather than the print head. With a few tweaks to the software, he could then print full-height elephant slices to speed up the process. He is absolutely right: while it is tempting to endlessly fiddle with a concept on paper, you learn more by building a prototype, even if it doesn’t work.

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