Author Archives: john
This project is about using embedded Linux devices to detect, record and react to seismic events. The idea is to use accelerometers to detect shaking and then communicate this event to all other devices connected to the same broadcast group. We are developing the technology using OpenWrt which allows us to use a range of [...]
Recently I was revisiting a powerful open source search engine technology on a Ben NanoNote to see how well it performed. Bearing in mind the NanoNote is only equipped with 32MB of RAM and a 336MHz MIPS processor it performed admirably. As a proof of concept I took the PDF lecture slides from three MIT [...]
Twitter pulling the plug on basic authentication meant I had to make changes to btlogger to support OAuth. Fortunately, librest made the code changes trivial. However, I ran into some problems. The clock was out of sync on the PC where btlogger runs. This caused the authenticate process to fail at the token request stage [...]
Recently I have been working on Packedobjects which included redesigning the API and replacing a lot of C code in Scheme. I will try and formalize the whole encoding process which I have called Integer Encoding Rules. I also began work on a manual which includes some examples. My aim is to support the tool [...]
I have been hacking at the OpenWrt Makefile and now have command line history working within the REPL. opkg install http://zedstar.org/guile/libgmp_4.3.1-2_xburst.ipk opkg install http://zedstar.org/guile/libltdl_1.5.26-1_xburst.ipk opkg install http://zedstar.org/guile/guile_1.8.7_xburst.ipk Once installed setup a .guile file: root@BenNanoNote:~# cat /root/.guile (use-modules (ice-9 readline)) (activate-readline) When you run guile now you should be able to use the up and down [...]
To experiment some more with OpenWrt I dusted out a Freerunner and built a minimal image containing GNU Guile. The image is built with glibc and an IP 192.168.254.101 to match my Nanonote settings. ** UPDATE: GNU Guile now has readline support and root image now contains GLib ** Flash the following: http://zedstar.org/freerunner/openwrt-s3c24xx-2.6-uImage http://zedstar.org/freerunner/openwrt-s3c24xx-root.jffs2-128k Boot [...]
I personally view Scheme as a good extension language. Something that can be embedded into C code to ease the pain of doing everything in C. I am interested in exploiting this concept on embedded systems where there is a lot of fooling about to make a binary. I still intend to produce binaries and [...]
Received a Ben NanoNote today. It is a really natty little device with a lot of potential. My standard test on how hackable a device is involves getting Guile running. Anyway, it was pretty easy to accomplish this despite not using openWrt before. root@BenNanoNote:~# root@BenNanoNote:~# guile guile> (map (lambda (x) (+ x 1)) ‘(1 2 [...]
Having Guile running on an embedded device is very powerful. You can add scripting capabilities to a C program and avoid some of the cross compilation -> deploy cycles by simply editing the script to change some functionality. As an example I have taken the code from the excellent introductory article Scripting with Guile. I [...]