Category Archives: Uncategorized

Circular mirror idea for laser lithography

I have been working on using a laser to directly expose photosensitive PCBs for etching using a modified version of Henner Zeller’s design in the ldgraphy project. One of the major issues is that the focal point of the laser changes as it sweeps across the PCB, impacting the minimum feature size that can be […]

DSO Shell – A neat little kit scope.

The jyetech DSO Shell is a pretty neat little toy oscilloscope kit. It can only go to 100khz or so and is single channel, but it is actually fairly useful sometimes. Also, the fact it comes with schematics and source code is great for learning how scopes work. The main issue with it is that […]

Painless IPSec setup for a home network.

I have written a script to painlessly set up fully secured encrypted network traffic between systems on a small LAN or home network. Although more specialized than other IPSec solutions such as SWAN or Racoon, it does provide for the common use case of securing otherwise sensitive protocols such as nfs, dns, web based device […]

Cigar Box Breadboarding Tool – Part 1

As a kid, I always like those 300-in-One Electronic Project Lab toys. Although not really useful for real work, it was nice to have everything in one place. I decided to attempt to build one the way I want it to be. So far, I just have the power supply and external connectors set up. […]

Update on labeling your chips

A while ago I started ¬†labeling my chips¬†when breadboarding. Having a bin of properly labeled common jelly bean chips is just an extremely useful thing to have in arms reach when prototyping or experimenting with circuits. One thing that is annoying is having the decoupling capacitors right over the top of the chips blocking the […]

Experimenting with a homebrew time domain reflectometer

Have a big coil of wire you don’t know the length of? don’t bother measuring it, just measure how long it takes for a signal to go through it and multiply by the speed of light and there you go. Here is a simple one chip time-domain reflectometer. It consists of a pulse generator that […]

Label your chips.

It turns out the 6mm (1/4″) tape for the brother p-touch PT-1230PC computer controlled label maker is just about perfect for labeling PDIP ICs. I whipped up a small program to generate images from the chip pinouts and control the printer in raw mode to create labels. Next step is to put a QR code […]

Upgrading my reprap with cheap hall effect sensors.

How to modify your reprap to use cheaper, more reliable hall effect sensors rather than physical switches.