May 2014

Circuit Design&Electronics&Hardware&LogicAnalyzer&Projects31 May 2014 01:23 pm

I’m making a concerted effort again to post more often, we’ll see how it goes this time…

First a few quick notes about a few other things I’m working on that will probably see posts in coming weeks:

  • I’m nearly done building a Kossel Mini 3D printer. Related, not too long ago I worked with a friend of mine on a simple board to monitor force-sensitive resistors for bed leveling calibration, see his writeup here.
  • Caught the bug to build a 2-wheeled balancing robot; I’ve seen too many of these again lately… Only this time I have an electronics platform that can be easily repurposed for this project.


So, exciting times! The Logic Analyzer boards came back from OSHPark all pretty in purple as usual. It’s been a while since I did any serious PCB assembly but I still seem to be pretty good at it :)

Logic Analyzer rev1 PCBs

Freshly Baked LogicAnalyzers

This weekend, among other things I’ll be getting started on blinking some LEDs and making sure these boards work the way they should. More on this (and the other reflowed project pictured) later!

Electronics&Hardware&Projects17 May 2014 12:21 am

… At least not nearly quickly enough.

So, I have been pretty busy since my last post, but I don’t really have a whole lot to show for it.
The quadrotor project I talked about last has mostly been shelved for now, pending some other work investigating motor control in general (I’m mainly interested in stepper motors, but brushless motors are very similar), and all of that has been behind some other work, not all of which I’m ready to talk about yet. Relatively soon, though.

One other project that’s very important to me which saw some big progress recently is a Logic Analyzer project. The first big milestone has just been hit - I completed the circuit board design last weekend.
This project is intended to be like a swiss army knife, a multitool of digital electronics development and reverse engineering; Fundamentally it’s a high speed USB link to an FPGA controlled from a PC. The top things I want from it are:

  1. Logic analyzer type functionality
  2. Useful building blocks for in-system programming and testing; JTAG, SPI, etc, so I can wire it up to my stuff and program in a uniform way. Also without losing the logic analyzer functionality.
  3. Useful building blocks for reverse engineering; Being able to dump various kinds of flash, usable for characterizing systems, detecting jtag/etc ports.
  4. Platform to build more complex devices on; I can reuse the stack to make other more specialized USB connected devices quickly.

It’s a wildly ambitious project, and I’m building it mainly for myself with the things I want; however I’m making the design open if anyone else wants to follow along or try it out (or improve it!). Check it out if it sounds interesting at: – It will surely evolve over time, hopefully into something useful.
Once the PCBs come back for the logic analyzer and as I get further with the software/firmware I’ll be posting pictures and more details about how it goes. It should be a pretty fun project.

I did finally get tired of not having a 3D printer up and running (my electronics solution will still take some investigation time, and it still isn’t a top priority); and after the frustration of receiving an .. ehm … “mechanically challenged” 3D printer from a kickstarter project, I finally bought a printrbot simple v2, which has been working rather well, even more so with some upgrades like a heated bed. It’s really pretty amazing to be able to design a part and then iterate on the design several times over an afternoon to produce something that works well quickly. I still see a lot of problems I want to fix in the 3D printer space though, and will try to fix them. eventually…

There are some more things in the pipeline too, but I shouldn’t say too much or I’ll run out of things to post about again ;)