Hello, considering getting one of these ESR kits to build. Had a look on bangGood, and there are a few to choose from.
Can someone recommend the darling? Is bangGood best bet, or aliexpress/ebay offer better ones or prices?
M328 LCD 12864 Transistor Tester DIY Kit Diode Triode Capacitance LCR ESR Meter $22.85au
http://www.banggood.com/M328-LCD-12864-Transistor-Tester-DIY-Kit-Diode-Triode-Capacitance-LCR-ESR-Meter-p-1041588.html
DIY M12864 Graphics Version Transistor Tester Kit LCR ESR PWM $25.67 (cant see difference)
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-p-986954.html
DIY M12864 Graphics Version Transistor Tester Kit LCR ESR PWM With Case $31.58
http://www.banggood.com/DIY-M12864-Graphics-Version-Transistor-Tester-Kit-LCR-ESR-PWM-With-Case-p-997023.html
is the case worth $9 more. Seem to recall allignmnt issues.
GM328A Transistor Tester Graphic Wave Signal LCRRLCPWMESR Meter Inductance $20.44
http://www.banggood.com/GM328A-Transistor-Tester-Graphic-Wave-Signal-LCRRLCPWMESR-Meter-Inductance-p-997582.html
DIY Multifunction Transistor Tester Kit For LCR ESR Transistor PWM Signal Generator M328 $15.53
http://www.banggood.com/DIY-Meter-Tester-Kit-For-Capacitance-ESR-Inductance-Resistor-NPN-PNP-p-929603.html
Glad I'm not the only one bewildered by all the variants. Question is which one is the best.
I have several of these gadjets and my advice would be to try running it off a battery or a linear power supply. They do not like switch mode powers supplies at all
bill
I have the banggood diy and the clone with two switches on and I have found they do not like switch mode psus. both have encoders fitted, both work fine on battery but play up on psus. What i have found is that it is better to run them on battery when programming them as both have fallen over after being programmed on psus even though they verified without error YMMV
bill
I am very familiar with switch mode regulators. The output of my step-up 5v regulator has less than 50mv p.p switching noise and I even bypassed the 5v right on the encoder.
I would like to hear from other people that have or added the rotary encoder and don't exhibit this problem.
if your resistors are wrong, you could overload the pd1/3 pins when they are outputs.
that could drag the voltage down in the mcu and glitch it.
Looking at my display, I found out that the controller is designed for 3.3v and they simply drop the Vcc with two series diodes. Now I am not surprise that I am having this problem. I believe everyone else that is using this tester, this display controller and this encoder will experience this problem. And yes, I disabled the internal pull-ups on the processor (CFLAGS += -DPULLUP_DISABLE).
I was convinced that if I power the encoder from 3.3v that it will solve the problem but the improvement was minimal. I also tried a second encoder I had (the same manufacturer) and I got basically the same results. It looks like there is another manufacturer for these encoders, I might give it a try. Maybe someone else has a better idea.
Those diodes on paper would drop 5.0V to about 3.4 - 3.6 which would probably be OK for the display. I have one of those units (the only one to which I did not add any hardware extensions) and the voltage to the display is closer to 4.1V so I expect the display to die an early death. The diodes drop very little voltage at the current levels of the LCD. Disabling the pullups helps mitigate the potential damage to the signal lines but still is far from ideal solution and I believe that you also need to add a pullup resistor to PD0. On another unit I had (which came with a 3.3V regulator on the LCD board), I added an HC4050 to translate the 5.0/3.3 v signal levels.
Are the plans for a new schematic? I'll try to do it in KiCad, plus the PCB. I won't promise about being good enough, it will be my first try on KiCad and I didn't do one in tons of months.
it would simplify matters if we could communicate via the serial interface in both directions.
it would simplify matters if we could communicate via the serial
interface in both directions. i.e. RxD and TxD. Prefably SCPI style
or through a specific caommand set now that the ATmega 644/1284
provides much more memory compared to the "old" 328 the
memory of which is utilized to almost 100%.
The only thing I wish to have on this kind of tools is to be multi-platform #
I made a really simple one with processing only to use it on win and mac.
To keep the PC software stupid simple I modified the k firmware to add at the beginning of each sting sent to the serial port the number of the line and a terminator at the end of each sting.
How do you recognize the start/end of each sting/measure?
Have you implemented several conditions to distinguish the parts of the measurements?