Gravimeter plans in "Nuts and Volts" magazine

[Overtheedge]

Just got in Jan 2013 issue of "Nuts and Volts" magazine and in it is plans for a simple gravimeter using conductive foam as a gravity sensitive variable resistor. This instrument uses a PIC to convert RC charging time to percent change of G.

The author points out that this is a relative reading instrument and the foam will deteriorate over time. He also points out that barometric pressure can effect it.

But the price is roughly $30USD.

Many decades ago when I was a kid electronics nut, I played with different home-made capacitors. Most had some similarity to Leyden jars. So consider a variable capacitor patterned on a Leyden jar with the inner plate suspended on a bungee.

Anyway, just tossing it out.
eric

[Davor]

I've seen somewhere a similar project, but using a computer mouse with laser to measure displacement. Building it from the scratch would be expensive, but with a touch of scavenging spirit and using a ready made mass production device it becomes very cheap.