tw's blog

ET-3400 project notes

Some technical notes on wiring up an EEPROM to the ET-3400, for those interested. read more...

DimBot is timely

Reuters article “Dawn simulator curbs wintertime blues” reports claims that dawn simulation (what DimBot is designed to do) is almost as effective as bright light therapy, the current conventional treatment for Seasonal Affective Disorder (SAD). read more...

DingBot goes public with new protocol

I’ve replaced the network protocol on the DingBot with SprinkleNet, a much more robust packet-based approach that has improved reliability tremendously. And, there are now four completed DingBots in the world. read more...

Winter Solstice: DimBot 1.0

Unto us a sun is given! read more...

Robot Taxonomy

Having been playing with various electronic gadget designs that might or might not be considered “robots,” and recently thinking about buying a Roomba, I was wondering what my own working definition of a robot actually is. Here’s what I came up with while washing the dishes. read more...

DingBot in beta

The first DingBot unit is now finished and in use! read more...

PrayBot deployed

With a few new ideas for the last mechanical bits having arrived during my shower this morning, and a subsequent frenzy of Dremeling and hot-glueing, the PrayBot was in place and functional for the start of Summer! read more...

DingBot debuts

I’ve now got a running prototype of what we’re calling the “DingBot,” a paging system for use between the floors of our house. read more...

Sump pump alarm Mark II

I finished the second version of the sump pump alarm. This revision has the following changes: read more...

  • Sump pump alarm 2 3.9 V Zener (D1) instead of 5.1 V. This gives ~5.1 V to the PIC with a fresh battery. The PIC is rated down to about 3 V at the 4 MHz clock frequency used, so this keeps it running at least until the battery drops to 6.9 V, instead of cutting out at around 8.1 V. Depending on the discharge curve of a particular battery in this application, that could add some extra alarm time.

No news is good news; more news

Well, I replaced the ground fault interrupt outlet that the sump pump was plugged into a month or two ago, and I haven’t heard a peep out of the alarm since. So that must have been the culprit all along. read more...