Manhattan prototype pad layout planning methods? - Page 1
Forum section: electronics / beginners

author: djsb
author_rank: Super Contributor
timestamp: March 23, 2024, 05:31:55 pm
content: I'm just wondering if anyone has any favourite practical and efficient methods for planning the pad layout when converting a schematic into a manhattan prototype layout? I'm guessing that just using paper/pencil or a printout of the schematic and circling the connected nodes of the circuit elements would be the most direct method? Similar to stripboard layout in any way?In a few of the videos I have seen (I've not watched THAT many, so I may have missed some of the design stages-if any) most people have gone straight to the layout without seeming to do much planning at all. I could be wrong, though.I have thought that maybe I could do some of the sketching from within KiCad using some of the drawing tools. What are your thoughts? Thanks.

author: dobsonr741
author_rank: Frequent Contributor
timestamp: March 23, 2024, 07:15:27 pm
content: The Manhattan is about getting immediate builds and changes. So setting up Kicad footprints, possibly learning new tools goes against the grain.Often it’s just the schematics, drawn in a way it follows the natural alignments. Or, if a high pin count part is involved, drawn with that footprint represented instead of its symbol. All with pencil and paper, or in my case iPad and iPad pencil.And sometimes the schematics is not even ready - just pile up ideas, see how it works. Need a buffer? An attenuation, more filtering - no problem, soldered in right away.The working circuit itself is the documentation!

author: RoGeorge
author_rank: Super Contributor
timestamp: March 23, 2024, 07:24:35 pm
content: I would just use pencil and paper. Here is an example of planning the islands for the Manhattan style (first 2 minutes or so).#123: Build a crystal oscillator from schematic thru prototype construction and testing - DIYw2aew

author: David Hess
author_rank: Super Contributor
timestamp: March 23, 2024, 07:30:31 pm
content: I lay the major parts, usually ICs, out within the area of the board to minimize the length of the connections between them. High power assemblies like discrete amplifiers are laid out as self contained assemblies to minimize the length of high current connections; this can be more like plumbing than electronics. High gain circuit chains should be laid out in a line to prevent coupling from the output to the input.

author: tggzzz
author_rank: Super Contributor
timestamp: March 23, 2024, 07:48:23 pm
content: Manhattan is a good starting point for many circuits.Build your circuit a bit at a time, and test that bit before proceeding. Don't throw it all together at once!Understand the features that will determine circuit performance. For some circuits that might be low capacitance and high resistance at a specific node. For others it might be low coupling from component X to component Y. In most circuits it will be having short connections to a ground plane, and low impedance between power rails and the ground plane. Others might be dominated by high voltages or high currents.Plan those critical features, and implement them first.Afterwards fit other components where convenient.Use whatevercombinationof techniques suitsyour circuit; don't be dogmatic. For a range of techniques, seehttps://entertaininghacks.wordpress.com/2020/07/22/prototyping-circuits-easy-cheap-fast-reliable-techniques/

author: Doctorandus_P
author_rank: Super Contributor
timestamp: March 23, 2024, 09:21:38 pm
content: I don't agree with this:Quote from: dobsonr741 on March 23, 2024, 07:15:27 pmWhen I started with electronics 30+ years ago, I soldered most of my circuits on matrix board. Back then I quite often crammed the parts too close together and got into trouble because of this when the project is about 80% done. These days I draw at least most of the PCB in KiCad, even if I plan it's a one-off and I want to solder the thing on matrix board. I assume you do draw a schematic (Paper or PC?) and when you already have that in your PC, then assigning footprints, putting the thing on the PCB in your favorite CAD program is quickly done. And your software knows how big all the parts are. This is a great help for planning available PCB area. It's also easy to move sections of a circuit around to see what fits best. Doing that would be very inefficient with the physically soldered parts.And yes, there is a learning curve for CAD software. If you have not designed PCB's in CAD before, the first handful of them will be slow. but after that you have both enough experience, and you have a library that works for you with most of the parts you use and which you can reuse for your following projects.If I wanted to do Manhattan style, I would add test points to the schematic for the islands that are soldered to the PCB, and use a THT footprint of a testpoint for the PCB too. When using THT footprints (also for resistors & capacitors) you can route them on any copper layer. You can for example set the PCB to a 10 layer design, and this lets you assign different nets to your layers. this makes it quite easy to draw crossing wires in the CAD program, while in reality they will be air wired.And when finished, you have got a quite reasonable documentation trail for your project. You can for example use net highlighting to reference nets between the schematic and the PCB. When building Manhattan style, the circuit is often not finalized yet, but you are probably pretty sure about 80% of the circuit. When you build it "free hand" you have a strong tendency to build the circuit net for net, but when you first do it in CAD, then you can probably plan which are the "known good" parts of the project, and solder those first close to the PCB, while soldering the "this may need mods" part of the circuit higher up and with longer leads, This way the "known good" part of the PCB is under the parts that are likely to need modifications later.

author: RoGeorge
author_rank: Super Contributor
timestamp: March 24, 2024, 06:21:14 am
content: Quote from: Doctorandus_P on March 23, 2024, 09:21:38 pmMy first guess is the interference issues were because a matrix scratched PCB does not have a copper ground-plane. The ground plane helps a lot, because most induced parasitic goes rather to ground than to other nodes of the circuit.I'm taking Manhattan builds just as breadboard builds. Consider them a temporary draft, not permanent and definitive as a PCB design. Manhattan is for prototyping, meaning you can change your mind and rearange/resolder some components later. Doesn't have to be perfect. The advantage upon a breadboard is that a Manhattan prototype is soldered, and thus sturdy enough to use it later as a permanent circuit, plus it has a ground plane too. The ground plane is important for RF, and it is shielding, too.Usually it is for through-hole parts only (with long legs/terminals), and for small to medium schematics. If the schematic is too big, then break it in functional blocks/stages, and make each section on a different piece of PCB, then put them together. This way you can add sheets of tin can as a shield for each stage. Another thing I used to do, I was writing in pencil (on the schematic) the pin number circledaftersoldering that pin or component terminal, so to not forget any nodes or parts missing/unconnected.Also, for Manhattan you'll need a powerful solder station (or soldering gun - I'm using the former) to solder islands and terminals on a copper ground plane. Then, here and there I might miss a pad entirely, and just solder a node of 2-3 terminals in the air.The idea is to take it as a draft, temporary build, in which later adjustments or even failure is allowed. If it doesn't work, it only takes a minute to desolder everything and start anew.Maybe the question is too generic, so various advice, while correct, might not apply to your circuit. Attach the schematic you want to build, and let's start from there.