$20 LCR ESR Transistor checker project

[upsss]

I have compiled the latest available version k (702) with the option:

#CFLAGS + = -DLCD_SPI_OPEN_COL

And everything works perfect, so far nothing has broken and measurements go well.
The rotary encoder can be rotated at any speed without affecting the screen.

In these days I will be attentive to the operation in case something strange happens to report it.

Many thanks to all for the help and greetings

Hi, is this https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk/mega328_T3_T4_st7565/ the version that you used which fixed the problem?  If it is not then please provide a link to it.

Thanks

[pepe10000]

Exactly:

https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk/mega328_T3_T4_st7565/

I remind you that I have installed an AMS1117 3.3 for working voltage of LCD, resistors PULL-UP (attached image) and a crystal of 16MHZ.

I include image of another one that is in the process of assembly and improvements (even without putting the rotary encoder).

Good luck and I hope that works for you as well as me.

[edavid]

While checking my to-do list I've stumbled across CLDs/CRDs (current limiting diodes / current regulater diodes). A quick search shows that they are availiable up to about 5mA (high current ones up to 23mA), which can be handled by the transistor tester. Common types seem to be 1N5285 up to 1N5314. If you got some CLDs and like to support this project, I'd appreciate a few samples

They are just JFETs with the gate and source shorted, so you can use your JFET collection to test your code.

[upsss]

Exactly:

[url]https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk/mega328_T3_T4_st7565/[/url]

I remind you that I have installed an AMS1117 3.3 for working voltage of LCD, resistors PULL-UP (attached image) and a crystal of 16MHZ.

I include image of another one that is in the process of assembly and improvements (even without putting the rotary encoder):



Good luck and I hope that works for you as well as me.

Please clarify, your problem with the encoder rotation speed was fixed after you updated the firmware to version 702 or after you added the 3.3v regulator for the display with the external pull ups. 

At the time when I tried to fix this problem, I tried to lower the voltage to the LCD display by adding a third diode in series to the original two diodes (without any external pull up resistors) and that didn't make much of a difference.  My last firmware I used was whatever was the latest version about a month ago and I am not sure if that is the difference.

[pepe10000]

Exactly:

https://www.mikrocontroller.net/svnbrowser/transistortester/Software/trunk/mega328_T3_T4_st7565/

I remind you that I have installed an AMS1117 3.3 for working voltage of LCD, resistors PULL-UP (attached image) and a crystal of 16MHZ.

I include image of another one that is in the process of assembly and improvements (even without putting the rotary encoder):



Good luck and I hope that works for you as well as me.

Please clarify, your problem with the encoder rotation speed was fixed after you updated the firmware to version 702 or after you added the 3.3v regulator for the display with the external pull ups. 

At the time when I tried to fix this problem, I tried to lower the voltage to the LCD display by adding a third diode in series to the original two diodes (without any external pull up resistors) and that didn't make much of a difference.  My last firmware I used was whatever was the latest version about a month ago and I am not sure if that is the difference.

The speed of rotation of the encoder was fixed when I changed the line:

#CFLAGS + = -DLCD_SPI_OPEN_COL

The regulator of 3.3v and the resistances were already set before, I just mentioned it as additional data in case it was useful.

A greeting.

[upsss]

Sorry, I don't remember what was the default, you compiled with:

#CFLAGS + = -DLCD_SPI_OPEN_COL
or
CFLAGS + = -DLCD_SPI_OPEN_COL

[pepe10000]

Sorry, I don't remember what was the default, you compiled with:

#CFLAGS + = -DLCD_SPI_OPEN_COL
or
CFLAGS + = -DLCD_SPI_OPEN_COL

Original:

CFLAGS + = -DLCD_SPI_OPEN_COL

Fixed Encoder:

#CFLAGS + = -DLCD_SPI_OPEN_COL

[upsss]

What about the pull ups for the encoder?  They should be also pulled up to the 3.3v regulator.

[pepe10000]

What about the pull ups for the encoder?  They should be also pulled up to the 3.3v regulator.

No, I have the encoder PULL-UP connected to 5v, look at the photos from post #3006 for more information.

[upsss]

If you have the encoder pulled up to 5v, I think you are defeating the purpose of the 3.3v regulator.  I would just have to verify that these encoders are specified to function at 3.3v.

The entire problem stems from the fact that the processor is powered by 5v driving an LCD that is designed to operate at 3.3v.

[pepe10000]

If you have the encoder pulled up to 5v, I think you are defeating the purpose of the 3.3v regulator.  I would just have to verify that these encoders are specified to function at 3.3v.

The entire problem stems from the fact that the processor is powered by 5v driving an LCD that is designed to operate at 3.3v.

I have connected the encoder to 5v because this explains the manual in section 2.2.5.



The regulator is only installed because in the forum it was advised to set it so that the LCD worked at the voltage specified by the manufacturer.

Certainly all the problems derive from using an LCD that works at 3.3v, I have thought of replacing it with another one but the expense and the fudge that has to be done does not compensate, better buy a new one with all the options available like the GM328 for example.



But as the electronica is my great hobby I prefer to modify the ones that I have to offer me the maximum benefits possible and to maximize them.

A greeting.

[upsss]

Very well Pepe, if Electronics is only a hobby for you then you are doing a great job.  For me Electronics in not only a great hobby but also my profession.

As far as the Karl's original manual, if you interface a processor that is powered with 5v to an LCD that is also powered by 5v then of course you would want to power the encoder with 5v.  I did a quick search and I could not find a detail spec for these encoders so I am not sure if they can function properly at 3.3v which could be a problem.

In our case, to eliminate the problems we were experiencing you would want all outputs from the processor going to the LCD to be open collectors and all pull ups including the encoder and the LCD power from a separate 3.3V regulator as you did.  When I get some more time I will fix it for good.

[pepe10000]

It has also been my profession for more than 25 years, but now with the crisis I have been unemployed for 6 years, so now it is more a hobby, and having free time I can learn many more things.

When I solve it, I hope you will comment on the results, so it works very well for me at the moment.

I have only noticed a small fault and is that when you turn the encoder super-fast the tester restarts.

But under normal circumstances the encoder is never turned so fast.

A greeting.

[upsss]

Sorry to hear that you have been unemployed for so long, here the economy is not that good either.  Hopefully with our new president it will improve significantly.   I am an EE with over 30 years of design experience and now finally retired.

It would be interesting to know if you can try powering the encoder with 3.3v instead of 5v and hopefully that will fix your last problem.  Simply move the white wire that goes to the input of your 3.3v regulator to the output of the regulator.  I still didn't find a detail spec of these encoders so I am not sure if they will function at 3.3v but you have nothing to loose.

[stj]

the encoder is a physical switch, it will function at any low voltage

[upsss]

Sorry, that isn't true.   The encoder is a digital switch that produces 2 outputs that are 90 degree out of phase and the phase shift depends on the direction of rotation.  Like any other digital circuitry its Vcc has a certain spec.  As I said,  I could not find a detail spec to figure out if it will function properly at 3.3v.  If it uses TTL logic then it needs 5V, it it uses CMOS logic then 3.3v will be fine.

[Willem52]

These rotary encoders are used as digital switches.
But there is no digital logic inside of them. See also:
http://henrysbench.capnfatz.com/henrys-bench/arduino-sensors-and-input/keyes-ky-040-arduino-rotary-encoder-user-manual/#Keyes_Rotary_Encoder_Schematic

[madires]

Please see http://www.robotroom.com/Counter5.html for some nice tear-down pictures of a simple rotary encoder

[upsss]

Well, I stand corrected, you guys are right!  I just had to take one of these apart now, I guess this is NOT what I used to work with.

[madires]

At the moment I'm working on an alternative PWM generator especially for a rotary encoder and a display with more than 2 text lines. With a button press you can switch between frequency and ratio, while the rotary encoder changes the value. That way you don't have to select the frequency from a fixed list first. It works similar to the squarewave generator. BTW, would anyone interested in a dedicated servo test providing the proper PWM signal?

[mauroh]

+1 for the servo tester, if present I'll add a separate/external power souce to provide the proper current/voltage to the servo under test.
Mauro

[bitseeker]

BTW, would anyone interested in a dedicated servo test providing the proper PWM signal?

I don't work with servos, but sounds like a useful tool. Use the rotary encoder to change pulse width and, hence, position.

[edavid]

BTW, would anyone interested in a dedicated servo test providing the proper PWM signal?

I don't see much need for it, since everyone with servos to test has probably bought one of these: http://www.ebay.com/itm/1pcs-multi-Servo-tester-3CH-ECS-speed-controler-Power-CHANNELS-CCPM-meter-/172214381958

[Willem52]

It seems that they are selling the 'AY-AT color kit' now with extra functions added in the firmware.
https://www.aliexpress.com/item/2016-DIY-KITS-ATMEAG328P-M328-Transistor-Tester-LCR-Diode-Capacitance-ESR-meter-PWM-Square-wave-Signal/32732193545.html?spm=2114.13010308.0.0.duTKII

[all_repair]

At the moment I'm working on an alternative PWM generator especially for a rotary encoder and a display with more than 2 text lines. With a button press you can switch between frequency and ratio, while the rotary encoder changes the value. That way you don't have to select the frequency from a fixed list first. It works similar to the squarewave generator.

For brainstorming sake, it shall be good if there is an emulator for various type of PWM chips out there.  This can be helpful in troubleshoot switch mode power supply.   The supply works in a closed loop.  If the loop is broken, find the area that is broken is non-trivial.  As it is, it may not be possible for this checker.