Dead Bug Prototyping and Freeform Electronics
by HippyNerd in Circuits > Soldering
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Dead Bug Prototyping and Freeform Electronics
Dead bug prototyping and freeform electronics are a way of building working electronic circuits, by soldering the parts directly together, or through wires instead of the traditional way of using a printed circuit board (PCB.)
Dead bug prototyping got its name because when you invert a IC, and bend the legs out, it looks like a dead bug. Sometimes you can make your whole circuit work just by soldering the parts directly to an IC, and the easy way to do it is to lay the chip upside down, bend the leads out and solder parts together. Sometimes people use many chips, and glue them upside down to a blank PCB, then build the circuitry from part to part.
This type of circuit is often a quick way to get going on a project, and is a good way to test stuff, before investing in printed circuit boards, which makes it useful in prototyping, or even for building small quantities, but its fairly labor intensive, often difficult to build, and ends up looking ugly.
The neat thing about building circuits without boards is that it removes the need for everything to be on a plane, making for more interesting looking 3D circuits, rather than 2D circuits. Geometry comes more into play this way, and the way parts are manufactured, the number of leads, how they are organized all limit, and shape the way the parts can fit together. Some parts have 2 axial leads, others may have 2 or more linear leads or dual in-line leads, while another may have leads in a radial fashion. Surface mount parts and through hole parts have different properties, but they can both work fine and can even be mixed in the same designs.
When I used to work building electronics, engineers would revise designs, which would cause changes in manufacturing. We would do things like clipping a lead on a part, solder a different part on to that one, or sometimes on top of another part. It was pretty common practice to piggyback memory modules or chips to make a bigger memory module or chip. This sort of thing is practical and viable in many useful ways. Its also can be aesthetically appealing, and interesting looking.
The purpose of this instructable isnt to show you how to do this, but rather that its a fun way to build interesting electronic projects, as well as a quick way to see if your thing works.
Piggybacked Shift Registers
Shift registers are component often used in digital circuits, in this case, im using 74HC595 shift registers, they are very popular among hobby electrics users. They are a serial to parallel device, you send it a series of data, it outputs in a parallel fashion. Serial parts work well for piggybacking, typically the outputs are parallel, and the input is chained from one chip to the next, with several leads in common. The leads that are common, can be soldered in a direct line, that makes things easy, the outputs are also in a direct line, which makes thing nice and easy. The data chain is a simple repeating connection between one chip and another. Fitting it together in a stack isnt usually all that much of a challenge, but it can be.
Im usually using shift registers with LEDs, which means they often output to resistors, which can complicate things, but it can also make for more interesting designs. Stacking is by no means the only way to do this. but its one of the more interesting ways, particularly because vertical, is an uncommon direction to build electronics. It also illustrates how the parts work together to make one big part, like a hotel with many floors and many rooms on each floor.
LEDs
LEDs are also an interesting proposition for freeform electronics. LED cubes often use this style of building circuits in 3D space.
LED also work well with radial patterns, like the RGB LEDs in a 9 LED flashlight (shown above), or in a ring, like the first picture.
They work nice in a linear design too, as you can also see in a couple images.
LEDs typically come with 2 leads, but RGB LEDs need more, typically 4 or 6 leads. The charliecube spire is only works because the part uses 4 leads, each common lead is also connected to the complimentary anode/cathode lead, which is why it only works with 4 RGB LEDs.
LED cubes typically use a common plane, and that plane also works as a physical structure that holds the shape of the cube together.
LEDs often work good for points, lines, matrices, and cubes.
My first instructable, an LED cube
https://www.instructables.com/id/4x4x4-LED-cube-upg...
I have another instructable about building an LED cube.
https://www.instructables.com/id/Charliecube-Charli...
A fiber optic display that used some freeform electronics for the LEDs.
Quick and Dirty Prototype From Old Parts.
I needed a 3.3v power supply, to test running some LEDs and shift registers. I didnt want to run them at 5v, I wanted to see if I could get the voltage close to the LEDs forward voltage, to see if I could safely run LEDs with no current limiting resistor. Things didnt work out well, but building the test circuits went very well.
I started with a need for 3.3v, I dug though my pile of scrap parts and electonics, and found a promising looking voltage regulator, I looked it up, and sure enough, it was 3.3v. I took a couple minutes to look through the data sheet to read the specs, and found some sample circuits. I noted the components in the samples, and looks at the circuit board with the voltage regulator, all those same parts were nearby, so I removed those parts also. Then it was just a matter of putting the parts together in the right way, which I was able to do without a circuit board. The first photo shows where I found all the parts next to the completed regulated power supply.
The second photo shows how everything fits nicely together, and one of the output leads with a loop at the end for easy access.
The last photo shows the working circuit, including 8 RGB LEDs soldered to the shift registers on one side, and a thick wire on the other side of the LED. Except for the microcontroller there were no circuit boards used for this test project.
Sometimes You Just Need a Little Thing to Solve a Problem.
I needed a voltage divider, which is a neat way to use 3 resistors to split voltage. I needed 3 resistors that were the same value, but I didnt have enough through hole parts that were all the same size. I found a little SMT resistor pack, and figured out how to make the same circuit, using one part as 3 parts, that made one working votlage spitter. This part was very delicate, i broke a few before I got one good one, and it only had to last long enough to test a few things, so it solved my problem quite well.
Crystal CMoy Free Form Headphone Amplifier
Here are some excellent examples from other people. This first one is from another instructable. It ends up encased in clear resin. Im personally not to keen on stuff cast in resin, but I can see why he would need to do that here.
This is a particularly nice example, he goes to a lot of trouble to make each part fit with even spacing, consistent curves by using the same forming tool. He also does a good job forming parts without marring the surface, and solders the parts together without making a mess of the solder,
Arduino Skeleton
This one is an entire arduino uno done in freeform style.
This one doesnt have the artful craftsmaship that the last one had, but its still pretty awesome in that its rather complex, but yet all the wires seem to use the space very well, and mimic the way printed circuits are laid out.
Little Wire Dead Bug Art
Here is an attiny based blinky light freeform design. Its nicely built.
Geeky Advent
This is a whole tiny microcoroller project in freefrom. Its not too complex, but it is interesting enough, and this little guy even includes its own power source, which just frees it up a little bit more than other examples.
Atari Punk Console
This one is a good example of how to quickly develop a prototype by just soldering the parts together.
8 by 8 RGB Matrix
This was a prototype that I built using 64 RGB LEDs, 6 shift register, and a a bunch of resistors. The Shift registers are set up in pairs, deadbug style. To get the wiring to work out, I had one chip upside down, the other right side up. The inside leads are the input/controls, the outside leads are the outputs. The LEDs are also a deadbug style, the LED wiring structrure holds everything togehter, but the LEDs are also hot glued into place.
The idea was to use the 64 LEDs as a display that shines on the wall or ceiling. Sadly, the LEDs dont work very well as individual projectors, The R,G, and B LEDs within a RGB LED dont shine on the same place, and they dont shine in a nice 8x8 matrix. I had high hopes for this project, but I just dont think that its going to work out. the way that I want. Maybe with different parts (like SMT parts with external lenses? but this way didnt really do it.
Even if the project didnt work the way that I wanted, electrically wit worked great and is an interesting structure of circuitry.
LED Cubes
LED cubes are inherently freeform designs, You can build them with just the LED leads soldered to one another, or you can use additional wires. Additional wires can be anything from a roll of copper or steel wire found at any hardware store, to hardened steel music wire or electronic test pins found at a hobby store or electronic supply store. Bus wire should work as good as any bailing wire you find at the hardware store, but the best is probably the hardened steel wires you may find called music wire.
These are all 4x4x4 RGB(multi-color) LED cubes, they work in different ways, but they all do essentially the same thing. Some use shift registers, or LED driver, others use no additional components, and a third style uses a minimal level of discreet components (20 transistors and 20 resistors.) The wiring for each type of cube is unique to each electrical design, and that wiring forms a kind of geometry that is also specific to each way of solving the problem of controlling many LEDs. The cubes architecture is relative to how the LEDs are controlled. The charliecube uses 16 spires, each spire has 4 wires. The other cubes work more in a planar fashion, The work by lighting up only 1 plane of LEDs at one time, My transistor cube breaks each plane up into 4 separate lines, and controls the lines individually, which makes it different than the planar ones, but they work the same kind of way, and because they work a little differently, they need to be wired a little differently.
Build a charliecube:
The Clock
This is a last minute entry, Ive been looking at it since yesterday, and im blown away.
This project is so awesome in many many ways. This clock is made entirely from discreet parts. Nothing but Diodes, resistors, transistors, and LEDs. There are no ICs, no crystal, no input other than 12v, or buttons to control it. There are nearly 2,000 part, all soldered together to make this circuit work.
Instead of using a crystal for timing, like most clocks use, this one runs off the 60 cycle alternating current. It divides the 60 cycle in to 60 seconds, and uses decade counters and binary to decimal converters, no not the ICs that do that, but hand built circuits that do those functions. The 3 magnetic switches are for setting the time using magnets (not shown).
Look at this parts list:
1161 Diodes
340 Transistors
346 Resistors
60 Red LEDs
6 Magnetic switches
3 Dual digit displays
----
1916 Total number of parts.
I have made a few clocks, and im real partial to mixing the radial design with the 7 segments like shown here, but the real star is all those hand built circuits working together. He says it took him 3 years to design it, and hundreds of hours to build it.
Read all about it, and the other crazy freeform clock he made at: