DIY Test Equipment?

[Longhair]

As a beginner hobbyist that is still in the primary stages of learning, I am not able to justify spending a lot of money on expensive test equipment because I do not know how much use it will get. Of course things that I do find will need a lot of use, I will spend the money.

I bought a couple of Elenco through-hole kits to get me started and I enjoy the DIY assembly aspect of it.

What would be some good beginner / hobbyist level DIY test equipment that would be ideal to have?

[saturation]

If you like soldering and have no gear right now, a basic toolset at least is a DMM and power supply.  I think Elenco has these linked on the root page.  If you build them they should be decent and safe for use on DC only circuits and general other projects [ instead of batteries, that is.]

The AC Receptacle Tester w/ GFCI is useful, but it doesn't look like a kit.

 

[Longhair]

I have a good soldering station, the Rigol DS1052E oscilloscope, a couple of multi-meters and a linear power supply (1v to 30v / 30 amps) just arrived, so I am covered there.

One of the things I want to do is make my own Capacitor Substitution Box and 1% 1W Resistor Substitution Box but with tighter tolerance parts.

Is there any other general test DIY test equipment that you can suggest? Link with schematic would be very helpful.

[Simon]

is there anything that you need to test right now ?

[Alex]

The guys at Elenco could not fit the capacitor symbols on the PCB for the capacitor substitution box?   

[Bored@Work]

One of the things I want to do is make my own Capacitor Substitution Box and 1% 1W Resistor Substitution Box but with tighter tolerance parts.

If your interest is getting some project under your belt then sure, go for it. If you look for the most useful test equipment, unfortunately, these aren't.

Looking at your list of equipment, I'd say some kind of signal generator would make a good extension.

[Simon]

a basic signal generator is a good idea. The thing with making your own measuring and test equipment is that you may not be able to guarantee it's accuracy and "calibrate" it against anything unless you have some test equipment. Although if you have a scope you've got the first piece of more or less precision equipment

[saturation]

I recall the username of the OP built a signal generator in a prior thread?

Here's another type, its quite interesting in terms of performance, just saw it posted now but its is an advanced build:

https://www.eevblog.com/forum/index.php?topic=2024.msg27615;topicseen#msg27615

Substitution boxes are nice starter projects as they are very tolerant of soldering skill variation, and a good way to sharpen them.  As test gear its rarely used today because those parts rarely fail in modern circuits, and if they do, the replacement has to be exact.  The leads and simple act of placing into a circuit affect sensitive electronics, introducing spurious capacitance and inductance.  Its easier and more compact to have a small box of many resistors or caps, to get a set of alligator jumper cables, clip the resistor or cap to it, and clip the other ends on the test point; it will act nearly the same and be easier to store, and you can have a lot of values and multiple copies of them.

A history of those boxes are from a vacuum tube era.  Those components failed commonly in amps and radios.  The parts that failed were almost always among a set of common values, and it happened often enough to justify making a box, and they were crude enough that rotary and mechanical switch bounce, resistance and capacitance, were too small to be of any concern.

 

[Longhair]

For the most part, I want to build stuff that I would be able to use (or at least make life a bit easier) and I am looking for ideas.

The reason that I said test equipment is because that would be something that serves more of a functional purpose over a LED Christmas tree for example.

[saturation]

http://www.flippers.com/catalog/product_info.php?cPath=3&products_id=2

Schematic and build instructions:

http://www.flippers.com/pdfs/BlueESR.pdf


Also, there is Dave's ucurrent adapter:

http://eevblog.com/shop/index.php?main_page=product_info&cPath=1&products_id=1&zenid=a0afd10264dd85a30e85e84f5de970a0

But its already assembled.

[DJPhil]

There's always stuff to build!
Do you think you'll be working more with analog stuff (my guess, given your substitution box ideas), or will you be diving into the digital side of things?

There are a few LC meter projects out there if you're comfortable working with PICs. If you plan on working with switching power supplies, oscillators, or RF circuits then you'd probably find one of these very useful.

Frequency counters are also an option, with dozens of options available. You'd probably only get good use out of one if you needed more precision or bandwidth than your scope can provide, but they can be useful for RF work.

You could also build a curve tracer. These are used to plot the VI curve of a given part, and can be useful if you do repair work or component matching.

On the digital side there are dozens of various programmer projects out there for different microcontrollers, just pick your poison. Most folk would probably prefer to use the manufacturers hardware for programming to spare them the grief of wondering if it's the programmer when things go wrong, but there are some general purpose kits out there that won't go to waste if you just want to tinker.

If you're a fan of logic probes they make great projects, and you can add features until the thing is near sentient. Take the Super Probe for example.

It seems that people usually build their own test equipment to gain a capability that would be too expensive even from used equipment. Don't overlook the utility of building to suit though! If you have a frequent and recurring set of tasks, try and automate or simplify it by building your own gear. This could be as simple as building a continuity tester with ultra-fast response for testing boards, or a timer/agitator/extractor appliance for etching PCBs.

Hope that helps some.

[Mr J]

A great test equipment project is one of dave's function generators http://www.alternatezone.com/electronics/hsfg.htm

If you know how to program PIC's there is the frequency counter http://www.piclist.com/techref/piclist/weedfreq.htm

one of mine (very simple) AC line tester, see below. Notes: add a 100k from probe to ground.

[Mr J]

oh another is a CAT5 cable tester (easy) http://technosains.com/RJ45NetworkCableTester.htm

and a cable tracer AKA Fox and Hound http://www.pic101.com/foxhound/index.html

[Longhair]

Thanks everybody for the links and ideas.

[djsb]

This book may give you some ideas

http://www.amazon.co.uk/Instrumentation-Test-gear-Circuits-Manual-Newnes/dp/0750607580/ref=ntt_at_ep_dpi_12

David