Centipede (RoboMarkov)

Mark Hinkle had proposed a Centipede project different from that previously built by Brooks Coleman. Alas, the project page was only partially-captured by the Wayback Machine and I have no further knowledge of its successful completion.

The Centipede is a segmented insect-like robot. The segments are constructed such that they are removable and stackable. That is, the robot can be made almost any length you like.

I have been encountering some problems in the design definition stage. The big problem is that of knowing the turn angle. I would like to use a potentiometer for it but all the ones I have looked at have a high friction on the wiper. The robot is lightweight so this is unacceptable. If you know of a small, low-friction potentiometer, please drop me a line.

UPDATE (23MAR04): Some people that I have contact with through work are getting me the name of a manufacturer that makes 360 deg. pots. That is, the pot can turn infinite angles and has very low stiction. I’ll post contact info for the manufacturer as soon as I find out. It is exactly (almost … it is a bit large) what I have been looking for!

Failing that, I decided that a flex sensor would be a good choice. They only sense flexing in one direction so I would need two of them back to back. I figure they would have to be about one inch long. That means custom.

UPDATE: (23Sep2004) I have found a part that will do the trick! It is used on the nose-vane of the Predator UAV for attitude sensing. The part is made by the Dynamation Transducers Corporation.”

Mark Hinkle (aka RoboMarkov)

The background material for this page is derived from an archived page on the Internet Archive Wayback Machine. Some links may have been added, removed, or updated.

Campshower

Campshower is another design from the mind of Mark Hinkle. As is the case for his Centipede project, this page was only partially-captured by the Wayback Machine.

This is a concept for a deluxe campshower I have. This was going to be for the Civic Guard, a Society for Creative Anachronism group. Unfortunately no one had the cash to pitch in for its components.

Mark Hinkle

Some calculations for it follow :

Assume :
15 persons
10 minute showers
12V 200 Amp-hour battery
50 gallon water tank
2.5 gal/min pump
5 gal water per shower

Total shower length per day = 10×15 = 150 minutes per day

A fully charged battery will last 200/5.5 = 36.36 hours continuous usage.
36.36hr x 60min/hr = 2181.81 minutes
2181.81min / 150min/day = 14.54 days @ 150 minutes per day

A full water tank lasts (under continuous usage) 50gal / 2.5gpm = 20 minutes continuous (under intermittent usage) 50gal / 5gpp = 10 people can shower before tank is dry.

Note : this assumes that the showerer will only have the water on long enough to get wet or to rinse. No water usage during lathering, scrubbing, or shaving. Also, no account is made for the hot water reserve. I recommend that we have two water barrels so that one may be filled while another is used.

Another note : It can get cold at Gulf War. Pipes may freeze. How do we prevent that? We could bury the hoses but will that work? Draining is not practical. Also, we could use some sort of insulation on the uprights.

The parts list goes something like this:

BATTERY : spec.: AGM???, 12V, ???AmpHr, $xxx

BATTERY CHARGING REGULATOR : 10A Schottkey diode with heatsink if possible.

WATERPUMP : 12V DC, 6.0Amp current, 2.0-3.0gpm

HOSE : garden or RV hose with large inner diameter. Need something to prevent freezing. Bury?

FAUCET : two valve

SHOWERHEAD : low flow, high pressure

WATER HEATER : gas, 6gal, no electric (spark or match ignite)

STORAGE TANK :
calculation :
50gal@3gpm~=16min. shower,
40gal@3gpm~=13min. shower,
50gal@2gpm~=25min. shower,
40gal@2gpm~=20min. shower

Shower cannot be continuous! These times are the cumulative length of all showers.

PAVILION : plasticized canvas, 5ft.x5ft base

ASTROTURF : toolbox liner is also acceptable

PALLET : modified so feet don’t fall between cracks

The background material for this page is derived from an archived page on the Internet Archive Wayback Machine. Some links may have been added, removed, or updated.