# How to measure anything with electronic instruments

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I had the opportunity to pick up "How to measure anything with electronic instruments" (John A. Keucken) from the local Half Price Books store. The book consists of circuits, schematics, diagrams, and some basic theoretical explanations.

All pretty neat.

Are there any other resources for making "any" electronic instrument or measuring anything? More recently, my interests have been in figuring out how to do chemical analysis ("do it yourself" chemistry instrumentation), though I would appreciate the help of anybody with some information and links.

- Bryan

BTW, contents of the Keucken book specifically include: zero current voltage measurement, ammeter, resistance measurement (ohm meter), vacuum tubes, emitter-stabilized transistor, balanced amplifier, ideal op amp, (non)inverting amplifier, summing/difference amplifier, voltage-to-current converter, current stabilized zener, current-symmetrical regulator, capacitive effects, phase shift in amplifiers, audio frequency measurements, differentiator, sliding comparator, active filter, quartz oscillator, frequency counter/divider, pulse synchronizer, voltage to frequency, flash converter, ladder netwrok D/A converter, cathode ray oscilloscope, digital oscilloscope, silicon diode thermometer, calorimeter, thermal ammeter, distance counter, linear voltage differential transformer, interferometers, Doppler shift measurements, manomater, diaphragm gauge, ultraprecise gauge, tachometer, and an ignition system.

ISBN 0830600256

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Usually there are different components, you have first some kind of transducer, that converts a "physical" quantity into an electric quantity.

Then you have a signal conditioner and and amplifier, that tunes up the signal into a volt value that goes into the A/D converter. Then you usually have a computer interfact so you can log it.

I've dont alot of toying and there is alot you can do at home. First I'd get a simple PC connected A/D converter, say an USB device or something.

Then you can toy around with the conditining and transducers. I've made pulse counters (from diodes and photosensors) to be used as flow meters, I've made simple photometers using the same components where you can measure absorbance. I've also hooked up various gas sensers, for example the type of sensor that sensens EtOH vapours in alcohol meters, these you can buy for 2$and hook up. I was able to get amazing resolution just hovering it over a glass of beer. OF course to handle long term stability and temperature drift you may need more fancy electronics and quality components. You can hook up homemade electrochemical cells. Electronic component vendors usually have a section for single chip sensors, that are fun. From gas sensors, photosensors to humidity sensors. Those you can usually buy for a few$ and if you are handy and have a soldering iron you can have fun with little money.

There is alot you can toy with at home, for not alot of money, but I don't know of any guides though. Good luck.

/Fredrik

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the easiest "Pulse counter" is to buy a cheap calculator take the = key off and extend 2 wires from it.

then type in 1+1.

each time you touch the 2 wires it counts

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Here is an old pic my simple home made bubble counter I made for my beer project

I also made an acoustic prototype wich basically was a microphone, and the characteristics of the sound pulse could distinguish the sound of a bubble from ambient noise (human talk etc).

Both prototypes worked, but was sensitive and a hassle to calibrate So I ended up finding a pro mass flow meter on ebay that I got instead. However the beer projects are not put on ice as they take too much time.

The flow meter was to track the beer fermentation process and get gas flow vs time. In parallell I am/was working on a computer simulation on the fermentation process, including yeast growth and metabolism.

Usually the fun part is solving the problems, once the problem is solve it's boring and you never use it again

/Fredrik

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The local chemistry teacher had us making miniature hydrogen bombs today, which included some procedures to react magnesum and hydrochloric acid to get hydrogen gas. Which, apparently, when ignited makes an explosion ... need to find some time to play around with this.

I have identified some interesting relevant-to-the-topic websites after two or three minutes of searching:

* And some information that I have been assembling on atom lasers, coherent matter-wave beams, atom holography, etc.

Fredrik, what other devices and apparatuses have you built?

- Bryan

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I guess I didn't build that awfully much really, I just tried to find cheap do-your-own solutions for a few things, mostly related to my yeast/fermentation projects on an as-needed basis, whose emphasis was really the computer simulation, and a learning study of myself. The whole point was that I avoided all biology in my previous life, so it was an interesting journey where I learned alot set aside the yeast itself.

I did consider trying to built some kind of chromatograph by making some home made column and detector but never continued the testing.

I exploited a simple diabetes bood sugar meter for beer analysis. the enzyme assay based on GD/PQQ designed to measure blood glucose, does have sensitivity to other reducing sugars like maltose and maltotriose which happens to be just want I want, so I've made very simple beer analysis with a plain blood sugar meter. It has the teststicks, and then you put htem in the digital meter and get a readin in a few seconds. I did a series and concluded that the standard deviation of the method was bad, but with a larger series is was usable. Easier than titrations as it takes seconds.

I've toyed with staining as welll, a qualitative estimation of glycogen level in the yeast cell was made with iodine staining of yeast. Then you can hold a normal digita camera over the microscop and then do RGB analysis on the image.

I also has some ideas to do decode measurements from simple conductivity and capacitance measurements. But things got in the way so I never completed it.

Of course all normal sensors are easy to hook up, pressure and temp.

You can also built your own scales with strain gages. Commercially, the most expensive parts is the condition amplifier unless you built your own.

I got some IR sensors that I was hoping to something fun with but never got to it either. I think I got one of those magnetic sensor as well, same story. Check your electronic component vendor for fun usable components.

But now since I resumed the physics project I have no time for the fermentation project So it's frozen atm.

/Fredrik

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The local chemistry teacher had us making miniature hydrogen bombs today, which included some procedures to react magnesum and hydrochloric acid to get hydrogen gas. Which, apparently, when ignited makes an explosion ... need to find some time to play around with this.

- Bryan

My favorite way to do this is to use a tall, thin glass bottle, carbonated beverage type is good, with a round lip on top over which a toy balloon may be tightly secured after HCl and (usually), small chunks of Zn metal have been introduced. The rate of reaction may be too fast if conc. HCl is used. Do not allow the balloon to burst! When of reasonable size, pinch off and seal it's outlet. The balloon will be very light. If any flame is brought near the balloon, the sudden release of hydrogen gas combining with oxygen in the surrounding air makes a very impressive concussion! Use a LONG stick, at least a meter long (longer preferable) to bring the flame toward the balloon!

The product of combination is, of course, water vapor. imp

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the easiest "Pulse counter" is to buy a cheap calculator take the = key off and extend 2 wires from it.

then type in 1+1.

each time you touch the 2 wires it counts

What an idea!!

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