Compiling Net-SNMP for PowerPC running Embedded Linux

I was recently requested to get SNMPv3 up and running on a PPC board running Linux. It needed to support hardcoded views, creation/deletion of V3 USM users in runtime and allow for three security profiles: none, MD5 authentication and MD5 authentication with DES encryption. The obvious choice is to base this on Net-SNMP, but I first tried to use the version precompiled and included in the ELDK. By simply loading the appropriate binaries on to the target, I quickly got an SNMP agent functioning. There were two issues:

1. The version was compiled in a certain way that took up a lot of flash space (openssl was required as an external shared library)
2. The version was pretty old – based on the 5.4.x branch

For fun, I downloaded the ELDK source RPMs, unpackaged, tailored the RPM spec, rebuilt and installed it on to my ELDK library. Sure enough, I got a much smaller agent but decided I want to use the latest and greatest Net-SNMP, 5.6.1 at the time of writing. The build process below assumes you have ELDK 4.2 installed on Ubuntu. You can check out a recent post of mine for detailed installation instructions.

Repairing FreeNAS after a power outage (FreeNAS rebooting)

For reasons beyond me, I have a storage server set up with FreeNAS. I find it convenient to have all of my movies/music/TV shows on a PC that sees no action besides reading and writing to its drives. This weekend, while streaming a show from my storage server, the power went out. The server is connected directly to mains, so it went down – hard. To be fair, my Ubuntu based media center PC also died, never to recover. After a bit of troubleshooting and an annoying secondary problem, it seems to be up and stable.

My FreeNAS server is based on a 4 year old AMD 3200+ PC. Before setting everything up I made sure to clean the motherboard and CPU mount, applied new thermal grease on the CPU heatsink and upgraded the PSU to a Thermaltake 480W PSU – I really wanted to reduce chance of having any electrical/heat related issues that would take out the system.

Building and deploying U-Boot and Linux for a PPC8xx board

This post describes the steps required for setting up an Ubuntu based compilation and debugging environment for U-Boot and Linux 2.6 w/a JFFS2 filesystem on a custom PPC board, using an Abatron BDI3000. It mostly discusses the environment and doesn’t dive too much as to how to customize the packages for your specific board (this is the hard part, but also extremely board specific). While you will probably not follow this guide from start to finish, it serves as a reference for what is the minimal amount of work required to build U-Boot and Linux for a PPC8xx board and a supplement to the DENX DULG, which is a must read.

It assumes that Ubuntu is already installed on the station, but nothing else. On the host side we mostly need the ELDK – a single package that contains all the cross tools needed (compiler, linker, debugger, tools to generate a file system, etc.).

Rotary encoder based cooking timer

Continuing my experimentations with cooking timer user interfaces, I stumbled upon a cute little rotary encoder on Sparkfun. It immediately looked like a good match for the project. The thing is that all cooking timers I’ve seen have either a simplistic interface requiring many clicks to set the time (like clicking the “minutes” button 50 times) or a complex keypad with way too many buttons.

At first I thought I’d need 2 axes (axis 1 would increment by 1 minute and the other axis by 15 minutes) but fiddling around with the trackball showed me that it was not necessary; that I’d just need one axis with tactile feedback (that is, a clicky switch rather than a smooth flowing motion of the controller) and some selection mechanism to switch between 1 and 15 minutes.

Video Review: Dremel 220-01 vs. Proxxon Micromot MB 140/S

Started fabricating PCBs at home using the toner transfer method and needed to find a way to drill them, as I am still mostly using through hole parts. Since I was pleased with my Dad’s dremel 300, I thought it would be a good idea to get one for myself along with a Dremel 220-01 (220) drill stand. It took me a few minutes of painful work with the stand to realize just how bad it is for the job – it flexes, it’s plasticy and it’s an insult to Dremel users.

I got a tip to check out the Proxxon Micromot MB 140/s and IB/E, which costed me dearly. I was blown away by how stable it was – felt like I was working with a surgical tool. To make a long winded youtube video short – the Dremel is bad for drilling PCBs and the Proxxon Micromot MB 140/S and IB/E are good. I got my solid carbide bits from BitGuy1 and was very pleased with the service and the bits themselves (they are used, but plentiful – good for amateurs like myself). He has many bits unlisted – just ask him if you can’t see what you’re looking for.