Hobby Projects - Insulation tester, LED Circuits, Meters.

Tuesday, February 21, 2012

David Bray 1-Wire Barometer

This article describes details for constructing a 1-Wire Barometer which will work on a Dallas Semiconductor Corporation 1-Wire network. This design differs from the popular Version 1.1a in that it has more than twice the resolution. - David W. Bray

1-Wire Barometer - 5/10 Volt Design

"The circuit requires an additional power source other than that of the 1-Wire network. The MPX4115 requires about 7 ma of current. This is more than a 1-Wire network can provide without an elaborate circuit to store parasitic power from the 1-Wire network for short burst of current for pressure measurements."

David Bray 1-Wire Barometer

Wire Drivers-Getting Started

1-Wire drivers allow communication between a personal computer and Maxim's 1-Wire or iButton products, and they are provided for download free of charge. Also bundled with the 1-Wire drivers download is the OneWireViewer demonstration application software. To get started, you will need the following:

Monday, February 20, 2012

Battery Level Indicator

This circuit uses a LM339, a quad comparator. LM339 can work on single or dual supplies, it has a open collector output that can drive 15mA, low power consumption. The circuit is an untested design but it should work. I did it as many searches were made in my webpages with these keywords.

There are many better circuits in the various circuit archives i have linked on the front page, you just have to look around. When you measure the open circuit voltage of a battery with a high impedance DMM (10M), the value may be a bit misleading. Apply a dummy load to bleed the battery a bit so that proper readings can be taken on Load. The load below is a 100 ohms wire-wound fusible ceramic resistor which will heat a bit when you test 12V batteries.
Battery Level Indicator

Theory of Operation.

R16 a 5W ceramic wire wound bleeder or dummy load. R15 is a part of an attenuator for obtaining ranges. D2 is a protection clamp diode. R10-D1 forms the 5V reference for comparators. Then an attenuator obtains 1.2, 1.4, 1.6, 1.8 V steps for each comparator. This circuit is similar to Audio Level meter or VU meter circuit.

The comparator compares the battery sample voltage to the fixed reference step. If '+' pin is more positive than '-', or is '+' is more dominant, then output goes floating 'open collector', so No LED light . But if '-' is more dominant the output transistor of comparator goes low impedance or saturates or turns 'ON'. But only spec current can be switched, do not compare with electrical switch 'ON'. Also on a dual supply 0V is more dominant or positive compared with -12V, even though it appears -12V is a big number. The direction of current is what decides, all measurements are relative.

More Information

Thursday, February 16, 2012

MakerSpace Hackerspace and TinkerSpace

I am using the word MakerSpace for the same Hackerspace. I would rather call them plain TinkerSpace, where youngsters take apart, fix, build Hardware, Software, Webware, Robots and Machines.


Sony used to get the abandoned ww2 radios in the islands to design, make and sell their first radio units. Honda used to fix bikes from europe and america to gain the skills and mutate to a global giant. Take apart, reverse engineer, fix and learn.

Hackerspaces are community-operated physical places, where people can meet and work on their projects.This website is for 'Anyone and Everyone' who wants to share their hackerspace with international hacker's'paces.

Every kid is a born hacker and he starts with his toys, his mom does not like that, but he does not stop. One day he is building something pretty big.

Dallas Makerspace Wiki - Membership based, non-profit, shared community workshop and laboratory.

Milwaukee Makerspace - Social club for people who like build, invent, tinker and/or collect new skills and expand their minds.

In the late nineties and the early 2000. There were Hobby DIY Groups, Ham Radio Groups and Learning Electronics Communities. Hackerspaces by function, may be as old as technology itself. People working in a garage or shop to learn skills or build-invent something, but with different names like "Metal Tinkering Club" etc..

Recently the people at Make created a more organized and sustainable movement, that is helping the "MakerSpace" Phenomenon Emerge - Makezine - MAKE brings the do-it-yourself mindset to all the technology in your life.

Wednesday, February 01, 2012

What a Hat can do – RobotGrrl.com

"I was goofing around the other day thinking of ways that I could use NFC with RoboBrrd. I got a few NFC tags and was also getting a robot achievement badge (thanks Adafruit!), so there had to be some way to connect these things.." - What a Hat can do

RoboBrrd from RobotGrrl.com!

What a Hat can do - RobotGrrl.com

This is an Interesting Life Form. The RoboBrrd reminds me of Ancient DictaBird from The Flintstones (1994) Movie.

 DictaBird.

I would prefer one that that may be useful on the Desktop like the DictaBird. That reminds me of another Bird called 'SMS' in Asterix and the Vikings. So an Interactive desktop communication helper in the form of a Extra-Smart bird. Like Daisy perhaps. Something Fuzzzy or with AI like

The Billy Project - DAISY

Daisy's primary purpose is to be able to converse with humans.



"What separates Daisy from Billy (and most other chatbots) is that Daisy has no pre-programmed (or hard coded) language of any kind. She starts with no knowledge of anything, but then is able to gain knowledge as she observes what humans say. From this, she is able to remember patterns of words, and the probability of these patterns occurring. Using this data, Daisy is able to actually generate her own.."

See above is another green bird, it could have been inspired by the DictaBird. He is Peedy the Green Talking Parrot, he also happens to be an MS Agent.