Finding Raspberry Pi’s

I’m using Raspberry Pi’s for all sorts of projects. They’re fabulous, inexpensive computers that run Linux and can interact with the physical world. But sometimes, I have trouble finding them on my network. I know they’re there but I don’t have any idea of their IP address. For Pi’s that are connected to the display, keyboard and mouse, this isn’t much of a problem. But when the Pi is running headless, it’s a bit annoying trying to find it.

An easy way is to use nmap to find the all hosts on the local network with a specific MAC address prefix. For Raspberry Pi’s, there are two: B8:27:EB for older RPy models 1, 2, 3 and DC:A6:32 for RPy 4.

#! /bin/sh

nmap -sP | awk '/^Nmap/{ip=$NF}/B8:27:EB/{print ip}'
nmap -sP | awk '/^Nmap/{ip=$NF}/DC:A6:32/{print ip}'

nmap will find hosts on the specified network and awk will pull out the IP address of the host if the MAC address prefix matches those of the RPy’s.

Note that you’ll need to change the to match your local network.

LPG Cylinder Sizes

On a regular basis, I’m building flame effects that are fueled with propane. Invariably for the larger effects, I’m scrambling around looking for specifications and details on propane cylinders to just how long an effect will run given a certain amount of fuel, or how long before this effect freezed the cylinder, or what are the basic dimensions to know how to build the mounting mechanism(s) for the cylinders. So here’s the first table showing basic dimensions and weights associated with propane cylinders. For the curious, the 20# cylinder is what you would typically next to a BBQ.

cylinder size lpg gallons weight empty weight full width height orient vendor model
100# 23.6 68# 170# 14.5 48 vert
40# 9.4 29# 70# 12.5 29 vert
30# 7.1 24# 54# 12.5 24 vert
20# 4.7 18# 38# 12.5 18 vert
12.2 49# 100# 12 28 horiz Flame King YSN122a
20.3 78# 163# 16 27 horiz Flame King YSN203
29.3 97# 220# 15 48 horiz Flame King YSN293
16.4 81# 150# 14 40 horiz Manchester 6828
11.3 69# 116# 12 32 horiz Manchester 6817

Burning Man DMV Application

The application for Most Useless II has been submitted.

Fingers crossed.

Most Useless II

The first time I went to Burning Man, I built an art car based on the idea of the most useless machine. It was an amazing experience working with friends to bring it into being and cruising around the playa with it. Unfortunately, there were issues with the design of the internal mechanisms that worked less well than expected. I’m planning finally going to remedy that this year.

I’d like to introduce Most Useless II!

There’s a level switch in the back that when pushed forward causes a trap door to open, a hand come out to push the switch back and the hand retreats back into the trap door again.

Since this is for Burning Man and I want to be able to drive around at night, there will be led lights flooring the ground from under the vehicle, from around the outside of the frame and from the canopy.

Most Useless II will be built on a Taylor Dunn B2-10 electric hauler.

This was last used for K9 Mark IV-BM.

K9 Mark IV-BM (2015)

I’m currently in the design / idea phase. The next step is to get an application into the Burning Man DMV to see if it’ll get an invitation to attend this year. Here’s hoping!

Amateur Extra

I’m now a licensed Amateur Extra!