Author Topic: Ten Dollar Frequency Counter's - Thread #2  (Read 14208 times)

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Offline TheBay

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Ten Dollar Frequency Counter's - Thread #2
« on: September 11, 2016, 05:03:59 am »
I couldn't reply to the existing thread so continuing in a new thread, mods may want to merge threads however  :-+

This is the existing thread: https://www.eevblog.com/forum/projects/ten-dollar-pic-100khz-2-4ghz-frequency-counter/

Just thought I'd add an update to this thread, there seems to be a slightly updated version of this available now.
I picked mine up for £8.72 on eBay, shipped from Hong Kong, only took about a week to arrive to the UK.

The device was in a typical Antistatic bag and labled as a Sanjian Studios PLJ-8LED, the PCB silkscreen has the model PLJ-8LED-R5,

I have to be fair, I wasn't expecting much for the money but it works really well!, as I'm a radio ham as well it will have many uses on my work bench.

Differences I can see so far to other versions are:

PIC Microcontroller is not on the rear, it's under the LED Segment display, not sure of the type without connecting to it Via the ISCP port or removing an LED Segment, it appears to be a QFN package.
There is a TM1639 LED Driver IC on the rear.

Voltage regulator is a ST L7805CD Linear regulator, I noticed some other versions have a switching regulator so pleased about this.

This was advertised as up to "2.4GHz" Some are advertised as up to "1.1Ghz", the prescaler is a Fujitsu MB506 which is the correct 2.4GHz part, I know some came with MB501's, however I doubt I will be using it on anything over 500MHz.

I tried it out on a few things and am very impressed for the price, there is one Gotcha though on all of these... On the signal input the red wire goes to ground rather than signal input, just pay attention to the boards silkscreen rather than the cable colour, they could have rotated the socket on the signal input to resolve this.

Here are some pictures of mine, also a picture of the firmware version, you can get this by holding the top button while applying power, but this will reset your settings too.

I managed to find a English manual online, with some additional information added, however this is for the C3 revision, but aside from PCB Layout/Component differences the operation is the same:
http://www.zl2pd.com/files/PLJ-8LED_Manual_Translation_EN.pdf

This is the exact item/seller I bought it from:
http://www.ebay.co.uk/itm/191226437566










« Last Edit: September 13, 2016, 05:18:00 am by TheBay »
 
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Offline nugglix

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #1 on: September 11, 2016, 05:58:26 am »
Hi!

Also have some of these, from aliexpress.
They have the same problem w/ the red/back signal wires.

Thanks for the link the manual!

I like the IF feature, where you can add/subtract the measured frequency from a preset
value. Makes a great counter for a radio. :)

Unfortunately my version creates heavy spikes on it's supply rail.
And it draws *a lot more* power than advertised.
The little bastard is getting quite hot, at least from brightness 6 upwards.

But still, nice gadget. Will use it in my homebrew radio.

Oh of course, I also got a blue one.
Can anyone remember the time where there were no blue leds? ;)
 

Offline TheBay

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #2 on: September 11, 2016, 06:03:21 am »
I noticed the linear regulator gets a little warm but not hot per say, however a little heat is quite useful for the TCXO :)

What version are yours, it will say on the PCB Silkscreen. Has it got a linear regulator or switching?

Yes I remember when Blue LED's were first available, I put them in everything!

Also very interested in the homebrew radio, please tell me more :)

Hi!

Also have some of these, from aliexpress.
They have the same problem w/ the red/back signal wires.

Thanks for the link the manual!

I like the IF feature, where you can add/subtract the measured frequency from a preset
value. Makes a great counter for a radio. :)

Unfortunately my version creates heavy spikes on it's supply rail.
And it draws *a lot more* power than advertised.
The little bastard is getting quite hot, at least from brightness 6 upwards.

But still, nice gadget. Will use it in my homebrew radio.

Oh of course, I also got a blue one.
Can anyone remember the time where there were no blue leds? ;)
 

Offline nugglix

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #3 on: September 11, 2016, 07:17:27 am »
Just checked mine. Works down to 6V. Very nice.
OTH, the red led version needs a signal voltage of at least 150mVp-p.

Blue led version has the 7805, the red led version a LM2940-5.
In general my blue version draws a lot less current than the red one.

Both version miss the LDS feature shown in the manual you linked above.
And also I can only switch between 1s and 0.1s gate time.

Blue and red boards differ.
Will show some photos tomorrow.

WRT the radio:
will be a AM and 160m ham band super.
ATM I'm working on the local oscillator and first mixer.
I think I got the oscillator schematic, but still need to build it.
Mixer will be a NE602.
So nothing fancy. :)


Edit: spelling
« Last Edit: September 11, 2016, 07:21:43 am by nugglix »
 
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Offline TheBay

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #4 on: September 11, 2016, 07:25:03 am »
Will be interested to see the photos tomorrow :)

Mine also does not have the LDS feature, I thought that is because mine is in Auto, maybe this did not work well so they removed it from the firmware.

The radio sounds great! you should put the project up on here if you find the time, I'd love to see the work in progress.
I use 160m a lot, mainly for local rag-chew with friends but have had occasional DX, have got quite far with WSPR on 160m as well.

Just checked mine. Works down to 6V. Very nice.
OTH, the red led version needs a signal voltage of at least 150mVp-p.

Blue led version has the 7805, the red led version a LM2940-5.
In general my blue version draws a lot less current than the red one.

Both version miss the LDS feature shown in the manual you linked above.
And also I can only switch between 1s and 0.1s gate time.

Blue and red boards differ.
Will show some photos tomorrow.

WRT the radio:
will be a AM and 160m ham band super.
ATM I'm working on the local oscillator and first mixer.
I think I got the oscillator schematic, but still need to build it.
Mixer will be a NE602.
So nothing fancy. :)


Edit: spelling
 

Offline nugglix

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #5 on: September 11, 2016, 07:34:08 am »
First steps of my radio experiments are here:
https://www.eevblog.com/forum/rf-microwave/cheap-stable-vfo-design/msg950836/#msg950836

This probably needs it's own thread.
Thanks for beeing interested. ;)

Btw, I'm not a licensed ham.
Just want to build a radio since I was 10. :)
 
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Offline evb149

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #6 on: September 11, 2016, 07:51:53 am »
IIRC the older versions of these modules would not work (due to FW limitation, not HW limitation that anyone mentioned) below 100kHz.  Is that still the case with these newer versions?
As someone mentioned in the other thread it would be nice to be able to do things like measure 32kHz signals or whatever with these.
 

Offline TheBay

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #7 on: September 11, 2016, 07:59:44 am »
Sadly I don't have any way to test this below 100KHz, If I find a way of doing it I will be happy to try :)

IIRC the older versions of these modules would not work (due to FW limitation, not HW limitation that anyone mentioned) below 100kHz.  Is that still the case with these newer versions?
As someone mentioned in the other thread it would be nice to be able to do things like measure 32kHz signals or whatever with these.
 
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Offline nugglix

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #8 on: September 11, 2016, 05:31:01 pm »
Good Mooorning! :)

Here are the promised pictures.

First (boards.jpg) are the two boad versions I have.
Upper (unconnected) is the red led one, lower the blue one.
Quite different I'd say.

WRT to frequency measurement.
See freq_norm.jpg for a 12.7MHz signal.
Compare w/ freq_low.jpg, which is a 200kHz signal.
Both using a Siglent SDG2000X func-gen.

I wouldn't use this counter below 1MHz signal frequency...

Btw, pictures taken while running the counter from 6V.

I hope the quality of the pics is good enough.

Hope it helps!

Cheers
  Guido

Edit: spelling, what else  *sigh*  ;)
« Last Edit: September 11, 2016, 05:47:58 pm by nugglix »
 
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Offline TheBay

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #9 on: September 12, 2016, 12:17:01 am »
Good Mooorning! :)

Here are the promised pictures.

First (boards.jpg) are the two boad versions I have.
Upper (unconnected) is the red led one, lower the blue one.
Quite different I'd say.

WRT to frequency measurement.
See freq_norm.jpg for a 12.7MHz signal.
Compare w/ freq_low.jpg, which is a 200kHz signal.
Both using a Siglent SDG2000X func-gen.

I wouldn't use this counter below 1MHz signal frequency...

Btw, pictures taken while running the counter from 6V.

I hope the quality of the pics is good enough.

Hope it helps!

Cheers
  Guido

Edit: spelling, what else  *sigh*  ;)

Thanks for those pictures, yes they are certainly different!

I see the Blue one is a PLJ-8LED-R5 just like mine, I guess this must be the latest revision.
The Red one looks like it says PLJ-8LED-H2? but hard to make out.

I wonder if the red one has the LED driver under one of the LED's.

This layout has obviously been changed for a reason, assuming that's the reason the Blue one works better and uses less power.

Also will be interesting to mess around with the firmware, seeing as it has an ICSP socket, but I am yet to find any firmware files online.
 

Offline TheBay

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Re: Ten Dollar Frequency Counters - Thread #2
« Reply #10 on: September 13, 2016, 05:16:31 am »
Had another Frequency meter arrive today from China, cost a grand sum of £6.99

1-500Mhz range. Don't have anything here to test outside of that range.
This one is based around a Atmel Atmega 48PA, with a Fujitsu MB501 Prescaler.
The Crystal is a plain through hole 20mhz with a 40pf variable capacitor for adjustment.
0802 LCD Display.

I have to say I put this through a series of tests and it also seems bang on with accuracy!, this is fitted with a SMA connector and came with a small stubby antenna.
It's powered via a 9v battery.

There are 3 holes for jumpers on the back, I think one is to enable programming of the Atmega 48PA, had a play with the others and seemed to offset the frequency up or down depending on what jumper, will have a play around with that though. There are also points for a 6 pin ISP header for programming.

One thing that shocked me by pure coincidence is the person/company that shipped it was exactly the same person as the LED Frequency counter in my first post, even though it was a totally different Seller on eBay, quite the coincidence as there are 10000's of sellers in China of electronics on eBay.

Will 3D print a case for this, could come in handy as a pocket frequency meter.

This was the listing:
http://www.ebay.co.uk/itm/331873981044?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Here are some pics, the contrast on the LCD is better in real life and it still has the screen protector on it.







« Last Edit: September 13, 2016, 05:40:18 am by TheBay »
 

Offline bitseeker

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #11 on: September 14, 2016, 08:37:15 am »
As someone mentioned in the other thread it would be nice to be able to do things like measure 32kHz signals or whatever with these.

Perhaps try a lower-frequency module such as this one: http://www.ebay.com/itm/New-1Hz-50MHz-Frequency-Counter-Meter-Tester-Module-Digital-Red-LED-Display-J0Q5-/401173460259

Not as many digits, but supposedly covers 1 Hz to 50 MHz.
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Offline edavid

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #12 on: September 14, 2016, 09:08:28 am »
As someone mentioned in the other thread it would be nice to be able to do things like measure 32kHz signals or whatever with these.

Perhaps try a lower-frequency module such as this one: http://www.ebay.com/itm/New-1Hz-50MHz-Frequency-Counter-Meter-Tester-Module-Digital-Red-LED-Display-J0Q5-/401173460259

Not as many digits, but supposedly covers 1 Hz to 50 MHz.

There is another version of that one that is much cheaper:  https://www.aliexpress.com/item/DIY-Kits-RF-1Hz-50MHz-Crystal-Oscillator-Frequency-Counter-Meter-Digital-LED-tester-meter/32704505181.html

You have to assemble it yourself, and it doesn't have the BNC connector, but it seems like a good deal.  As usual, there are multiple sellers on AliExpress and eBay.
« Last Edit: September 14, 2016, 10:46:17 am by edavid »
 

Offline TheBay

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #13 on: September 14, 2016, 09:34:09 am »
As someone mentioned in the other thread it would be nice to be able to do things like measure 32kHz signals or whatever with these.

Perhaps try a lower-frequency module such as this one: http://www.ebay.com/itm/New-1Hz-50MHz-Frequency-Counter-Meter-Tester-Module-Digital-Red-LED-Display-J0Q5-/401173460259

Not as many digits, but supposedly covers 1 Hz to 50 MHz.

There is another version of that one that is much cheaper:  https://www.aliexpress.com/item/DIY-Kits-RF-1Hz-50MHz-Crystal-Oscillator-Frequency-Counter-Meter-Digital-LED-tester-meter/32704505181.html

I'm going to have to get one of these too!
 

Offline bitseeker

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #14 on: September 14, 2016, 09:36:33 am »
@edavid: Nice find! I hadn't started price hunting, yet, when I posted. Thanks for the link.
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Offline Alex Eisenhut

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #15 on: September 14, 2016, 10:23:19 am »
Do any of these come with a simple serial port output of the reading? With let's say a 1 per second dump at 9600 baud?
That would be immensely more useful than a display, really.
 

Offline ez24

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« Last Edit: September 14, 2016, 12:42:28 pm by ez24 »
YouTube and Website Electronic Resources ------>  https://www.eevblog.com/forum/other-blog-specific/a/msg1341166/#msg1341166
 

Offline bitseeker

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #17 on: September 14, 2016, 11:00:47 am »
Life is better under the TEA. ♪♩♫ Under the TEA. ♩♫
 
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Offline CJay

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #18 on: September 14, 2016, 04:01:52 pm »
These little counters are excellent value for money, they use a cellphone TCXO for stability and are pretty accurate out of the box, the ones I've had certainly compared well to my Racal with the high stability ovenised reference calibrated against a GPSDO/Rubidium standard.

The IF offsets are really handy too, selectable on the ICSP pins by applying a voltage, they make retrofit to a radio really simple.

WIsh I could find the firmware for the earlier version though as an unfortunate experiment with a PICKit3 means I've got a bricked one.

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Offline ElektroQuark

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #19 on: September 14, 2016, 05:07:41 pm »
How do those work? Do they autoselect the most powerful signal they receive with the antenna?

Offline TheBay

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #20 on: September 14, 2016, 06:50:47 pm »
How do those work? Do they autoselect the most powerful signal they receive with the antenna?

They need to be close to the device transmitting.
 

Offline TheBay

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Re: Ten Dollar PIC 100khz-2.4ghz Frequency Counter - Thread #2
« Reply #21 on: September 14, 2016, 07:01:12 pm »
As someone mentioned in the other thread it would be nice to be able to do things like measure 32kHz signals or whatever with these.

Perhaps try a lower-frequency module such as this one: http://www.ebay.com/itm/New-1Hz-50MHz-Frequency-Counter-Meter-Tester-Module-Digital-Red-LED-Display-J0Q5-/401173460259

Not as many digits, but supposedly covers 1 Hz to 50 MHz.

There is another version of that one that is much cheaper:  https://www.aliexpress.com/item/DIY-Kits-RF-1Hz-50MHz-Crystal-Oscillator-Frequency-Counter-Meter-Digital-LED-tester-meter/32704505181.html

You have to assemble it yourself, and it doesn't have the BNC connector, but it seems like a good deal.  As usual, there are multiple sellers on AliExpress and eBay.

This one looks interesting for testing Crystals.

The EZM Studio kit looks very nice if using BNCs, not sure if it can test crystals though.
http://www.ebay.co.uk/itm/New-1Hz-50MHz-Digital-LED-Frequency-Counter-Tester-Meter-7V-9V-50mA-DIY-Kit-K7S5-/311679573075?hash=item48918cdc53:g:oLwAAOSw65FXtX59
 

Offline TheBay

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #22 on: September 18, 2016, 11:35:16 pm »
Noticed something unusual about this LCD frequency counter, it seems to be transmitting a low power beacon on 446.000MHz FM Modulation.

Can't find any information about this device anywhere online, there are 3 jumpers on the back, 2 of those seem to relate to a + or - offset on the frequency displayed but both different values!
I wonder if this was originally designed for a specific purpose other than a general frequency meter?

« Last Edit: September 18, 2016, 11:36:57 pm by TheBay »
 

Offline mino-fm

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #23 on: September 20, 2016, 08:46:50 am »
Do any of these come with a simple serial port output of the reading? With let's say a 1 per second dump at 9600 baud?
That would be immensely more useful than a display, really.

Are you able to programm an ATtiny2313? If yes you can use 'fmeter20.zip' to get a frequency counter 0,005 Hz - 1 MHz (up to 200 MHz with prescaler). With 20 MHz Xtal baudrate is 38400. The LCD is not necessary at all.
http://mino-elektronik.de/fmeter/fmeter.htm

You can find another low frequency counter using Arduino UNO board with serial data output. First version 0,016 Hz - 250 kHz and 2. version with internal prescaler up to 7 MHz: http://mino-elektronik.de/fmeter/fm_software.htm#bsp7

A simple 5-digit counter is shown here: http://mino-elektronik.de/fmeter/fm_software.htm#bsp13

Sorry for german description.
 

Offline lovemb

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Re: Ten Dollar Frequency Counter's - Thread #2
« Reply #24 on: September 27, 2016, 01:24:00 am »
Noticed something unusual about this LCD frequency counter, it seems to be transmitting a low power beacon on 446.000MHz FM Modulation.

Can't find any information about this device anywhere online, there are 3 jumpers on the back, 2 of those seem to relate to a + or - offset on the frequency displayed but both different values!
I wonder if this was originally designed for a specific purpose other than a general frequency meter?

http://i1086.photobucket.com/albums/j457/thebayuk/EEVblog/20160912_194009_zpst7l83b0f.jpg

I just bought this one, arrived in 8 days from freaking china to europe! Was so excited to test it and it's crap..or something is wrong with it.

I try it with both 433MHz and 315MHz car fobs and it displayed mostly 145MHz and 202MHz and sometimes 50MHz. Thought it needed a longer transmission so I checked those cheap garage remotes (433MHz) that keep transmitting as long as you press the button(checked with RTL-SDR) and got the same unusable results.

I don't think I have anything to test it at lower than 315MHz, but at these ranges it doesn't work. I guess I will reverse it a little and scope it when I have time.

EDIT: I made a very quick schematic of the part that interest me just by looking at bottom pcb tracks, didn't dismantle it yet. (MAY HAVE ERRORS!)
Component values were copied from pcb silkscreen, not measured (yet)!


=
EDIT2: I just checked with the scope and I get 6.76MHz going to atmega48 input, x64(configuration from MB501L) = 432,64MHz!! (yet it displays something completely different like 175MHz)
So the problem seems to be in the firmware
« Last Edit: September 27, 2016, 03:16:45 am by lovemb »
 


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