Dangerous component/part tester

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Re: Dangerous component/part tester

Postby Sjaak » Tue Dec 13, 2011 7:07 am

arhi wrote:I don't have issues with OLED's myself, used them a lot with reprap project, but they are nasty .. either you have to solder them on board (and for that it's not "lot of flux" it's the very file iron, as I seen cable traces evaporate when using 350C soldering iron!!) or you need to use very complex easy to break and even easier to not work clamping mechanism ..


I also seen kapton with just copper tracks on top. They come in variuous types :)

arhi wrote:Now, one thing to remember with oled's is their pixels burn out !!! They behave like old hercules monitors, the material that glow burns out fairly quickly .. The reprap driver I used had some static text on oled while printing - that static text is unreadable right now as all pixels under it died. The part where "changing" text was is still there ... And note that this is after less then 1000 working hours (first pixels died after less then 200 working hours)


I had a carradio that had a special mode for this. It inverts the display every minute or so to equally burn in the display.
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Re: Dangerous component/part tester

Postby arhi » Tue Dec 13, 2011 7:34 am

Most connectors I seen looks like this one attached ... and one you see on picture burned out from 350C iron ..
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Re: Dangerous component/part tester

Postby omegat » Tue Dec 13, 2011 8:27 am

Hi Guys

I thought I share my thoughts on this with you..

I really like the component tester/superprobe idea, which would really make a great tool. However I think it would be wrong to include a breadboard area and or make the device non-standalone. It might be OK to have a non-standalone logic analyzer or a USB scope but when it comes to component testing or taking live measurements I think nothing is more annoying than having to click some kind of button on a computer screen.

I think the DCA-tester is such a handy tool because it is small, standalone and has only 2 buttons and 3 leads. Sure enough a tester/multiprobe gadget would need more buttons and some leads more but I like the general paradigm.

As for the display, graphic OLEDs are in fact dirt cheap; and could be controlled over a on-chip (parallel) memory interface (which would save space). But, as we saw, a normal alphanumeric LCD is sufficient (however I think the OLED version would be cheaper..).

The DCA meter seems to be powered from one of these 12V-batteries, which means we could try a CR2032/step-up power supply (CR2032s are dirt cheap, too).

As for other features such as a waveform generator or even an arbitrary wave gen (using I²C DAC), they were in fact nice to have, but they would complicate the project and make it a never ending story. It might be a great idea to add expansion capability though (such as an open I²C interface and or SPI) to later add things such as an arb (you need more firmwarespace then). An additional PC interface (firmware USB stack??) might in fact be useful, but should not be obligatory.

Once again I love the idea of a DP component tester Prototype :)

73s tobi
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Re: Dangerous component/part tester

Postby arakis » Tue Dec 13, 2011 8:41 am

best regards FIlip.
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Re: Dangerous component/part tester

Postby arupbsk » Tue Dec 13, 2011 8:46 am

omegat wrote:Hi Guys

As for other features such as a waveform generator or even an arbitrary wave gen (using I²C DAC), they were in fact nice to have, but they would complicate the project and make it a never ending story. It might be a great idea to add expansion capability though (such as an open I²C interface and or SPI) to later add things such as an arb (you need more firmwarespace then). An additional PC interface (firmware USB stack??) might in fact be useful, but should not be obligatory.

Once again I love the idea of a DP component tester Prototype :)

73s tobi

Yeah, true said. More functions will make more complexity. But the good is that various ideas from various minds open a lots of possibilities and development ideas.
I am not sure what will be decided and made by DP, but I'm personally on my way of developing the AVR board I made yesterday. Till now, I haven't sneaked into any of such project's source codes(which I wanted earlier, to add every subroutines I get, in a main function). I am on my way of making my own tester. Yesterday I succeeded in first ADC test, and tonight I'm going to make the resistor value estimator subroutine for my board. I have figured out a way to use the output pins as (1/Hi-Z) or (0/Hi-Z) instead of (1/0). This will help me develop further with the avrmega chip. After some hours I'll post up my success story(if I can).

Addition: 2x CR2032 or other low voltage battery for cost effect, not necessary. 9V PP3 batteries cost here 0.2$. :)
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Re: Dangerous component/part tester

Postby torwag » Tue Dec 13, 2011 9:14 am

Hey,

just came across this thread.
I am a proud owner of something like this

http://www.tulsa-ads.com/Red-Fork-/Hunt ... tester.JSP

The manual comes with a great detail of information showing graphs for all kind of defective parts vs. ideal curves.
I find the graphical representation much more useful and information rich compared to any kind of number.
Thus, I would vote for a larger (cheaper) GLCD instead of a OLED which allows to plot I/V curves etc.
This would give one the flexibility to have a quick mode (showing some numbers) and a very detailed (pro) mode really helping to sort out very nasty analogue problems. Having an USB option is nearly no option anymore, since I can't barley thing about a design without one (and if it would be only for firmeware updating)

Just my two cents
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Re: Dangerous component/part tester

Postby JanW » Tue Dec 13, 2011 9:22 am

In my opinion it's not a good idea to cram every possible device tester into a single device. The easier, the better (in terms of portability, size, weight, product cost, serviceability, component availability). It may be nice to identify/test/measure most active and passive discretes, but to include a full-featured logic IC tester would just bloat it.

How many crappy square wave generators and 3-channel logic analyzers :) do you need? Buy or build a Bus Pirate for the job.

Regarding the USB connection: What's the point of having a one-size-fits-all instrument when you have to carry a computer around to use it? But without a PC or similar the user interface will be a hard thing to get right.

Regarding I2C: Common I2C DACs have a 400 KHz maximum clock frequency. With an 8 bit DAC, you'd only get a meager 50 KHz update rate (even less when adding the start and stop bits to the calculation).

The IC tester would make for a nice separate project.

More than ten years ago, Elektor magazine published an article describing how to build a 74xx and 40xx logic series identifier/tester. The device was build around a 80C535 or -537 MCU in conjunction with two Z80PIO chips and a lot of other stuff. This instrument was able to identify unlabled logic ICs - you just had to put the DUT in it's socket and push start. Sadly the software was closed-source.

Back then, times were easier, because most of the logic families could be powered from a 5 V supply. For modern logic families it may be safe to power them all from a 3.3 V supply, but what happens to old TTL, Schottky (S series) or 74F ICs at undervoltage? I expect them to work at low speeds, but I'm not sure.

Because of this it may become harder today to accurately identify an IC without knowing any preconditions.
Maybe we should build an "IC verificator", which tests the DUT against the according truth table at a previously chosen supply voltage.

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Re: Dangerous component/part tester

Postby Pisami » Tue Dec 13, 2011 9:49 am

Just my $0.02: I'd like to use Li-ion/Li-poly cell to power up devices like this. The coin cell batteries here are awfully pricey. If I order them from HK, I get them cheap and most of them are bad.
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Re: Dangerous component/part tester

Postby omegat » Tue Dec 13, 2011 10:54 am

I see your point but LiPoly cells can be quite dangerous. Plus you need special charging circuits, voltage monitors, high impedance on-off switches etc.
I think with a solid 9V cell as suggested or some other kind of 'normal' battery (maybe 2 or 3 AAA [eneloop] cells - maybe on the backside of the PCB - or whatever) you're on the safe side, even when it's more expensive.
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Re: Dangerous component/part tester

Postby arhi » Tue Dec 13, 2011 11:01 am

Honestly - I hate charging batteries. There's no reason for this device to take up too much current and when using COG display's the total consumption should not go over 150mA. With a good DCDC a 9V battery should work for more then a year... or we can use standard 2 AA batteries in parallel and DCDC to 5V .. rechargeable batteries are imho wrong sources for this circuit
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Re: Dangerous component/part tester

Postby arupbsk » Tue Dec 13, 2011 1:44 pm

Resistor meter functionality was huge success tonight. Nice accuracy was achieved.
100_1767.JPG

Testing photos @ http://www.facebook.com/media/set/?set= ... e48fd95900
Now I have selectable resistor value-d pullups for the ADC pin. The same feature will be useful in capacitance and inductor measurement. I still have 18 I/O's left. I'll first finish the basic LCR meter part, then will add the semiconductor identifier/checker part. Then the frequency.......... zzzzzzzzzzzz
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Re: Dangerous component/part tester

Postby arupbsk » Tue Dec 13, 2011 9:37 pm

MickM,
I am building a fresh one with new code. When I looked into the source code of the semiconductor tester, http://viewvc.coremelt.net/viewvc/avr/s ... /?view=tar I saw some unexpected operations such as UART operations. I am unsure why the author is using UART. Also the project was done through AVRstudio.
In my case, I am using WinAVR-GCC package. If you want to take a look at my source code(achieved so far), I'll PM you. Note that the code missing explanations and is very messy now.
If you want me to test your .HEX file under my hardware(previous atmega8 one), tell me I'll try. :)
[There's seriously something bad going with the hosting, I got server not found for few seconds, then it was ok]
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Re: Dangerous component/part tester

Postby arupbsk » Wed Dec 14, 2011 10:13 am

Quite success in capacitance measurement.
100_1784.JPG

Seems like I need 14 days to achieve 14 features as my needs viewtopic.php?f=19&t=3260&start=30#p32215
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Re: Dangerous component/part tester

Postby BrentBXR » Wed Dec 14, 2011 4:13 pm

Really; man you should have used the mega8. Why waste a 328! so much space gone :) But the mega8 and mega328 are different even package size, you did not get any compiler errors when compiling?
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Re: Dangerous component/part tester

Postby BrentBXR » Wed Dec 14, 2011 5:04 pm

Oh for whatever reason I was thinking the mega8 was 40pin, my bad.

How big is the compiled source? Does your make say the size and whats left? I would still opt for the mega8 just because then you dont burn 32k on a 7k source. But then again; I have aton of AVRs so I dont have to be picky :) I guess if I only had one 32left and abunc of 64s I would use a 64.

plus that leaves room for more i guess.
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