What?? New Aneng AN888S combines Multimeter, Bluetooth speaker, and clock

[floobydust]

HEY from the ZT-5566 review, the DMM portion has a 5V DC-DC converter and two opto-couplers - it's isolated. DTM0660L serial data output pin 20 goes to unpopulated Q16 (Q15/Q14 seem to be a DNP protective clamp).
This means there is serial data communication between the Bluetooth and DMM IC... Possibly some delay for ANENG/ZOYI in getting an app finished?

If this did have a microphone... you could use it to hands-free answer your cell phone. That seems weird.

[ResistorRob]

I just bought one. I'm super excited!! I could care less about the bluetooth speaker, but I just love how sexy this thing looks. Will look amazing on my bench! Specs are good enough for just general purpose daily dicking around. I also like to collect unusual stuff, so this is perfect for me.

BUT!!!....

I didn't get the batteries because in the photo they looked like AA's, but are actually 18650's.  Can anyone tell me do I need the flat top or button top style to fit in this meter??

[flash2b]

I didn't get the batteries because in the photo they looked like AA's, but are actually 18650's.  Can anyone tell me do I need the flat top or button top style to fit in this meter??

You need button top LiIon 18650. Mine arrived just 2 weeks ago and I like it a lot. It's a great DMM and can measure resistance up to 200M, which is pretty amazing. It is also very fast in auto ranging.

HEY from the ZT-5566 review, the DMM portion has a 5V DC-DC converter and two opto-couplers - it's isolated. DTM0660L serial data output pin 20 goes to unpopulated Q16 (Q15/Q14 seem to be a DNP protective clamp).
This means there is serial data communication between the Bluetooth and DMM IC... Possibly some delay for ANENG/ZOYI in getting an app finished?

Once the meter goes standby, the clock is shown on the main display that is normally used for the multimeter. So I recon the clock uses the DTM as a display.

On the box the meter came in, there are two versions: with and without an APP. Mine is de without, but I think there might be a new version coming out later that has the APP connectivity.

[neo2001]

Also got the device a few days ago.

Here are some pictures of the PCB behind the front:
https://imgur.com/a/3WcAQlb

I was a little disappointed, since I was hoping for a known µC, but the two big ICs don't have any markings.

I bought this as a hobbyist simply because for the big display and the "form factor". The fact, that the power switch is on the backside is annoying, especially since there seems no real standby mode (the clock is always shown). Maybe I will relocate the switch in the future. The battery will charge even when the device is turned off - which is nice. The leads of the probes are actually really nice and soft, although they look the same as other, cheaper ones, they actually seem to have used silicone or a good quality PVC for the insulation.

The meter itself seems absolutely fine for a non-professional.

Also a little bit annoying is the fact, that the voltage value on idle changes all the time which is really disturbing because of the large numbers. As a solution I've switched to capacitance mode which stays on zero most of the time. ;-)

@ResistorRob: I'm using flat top (+) 18650s (Panasonic) and they work. The positive contact pad inside the battery holder is elevated in the center.

[TurboTom]

The big ICs are just LCD segment drivers, apparently with serial inputs. The BT / audio IC is a Jie Li AC6921, running under the family designation AC692N.
Apparently, there's no datasheet available.

But I managed to find the following schematic:



As it seems, hardware-wise it shouldn't be too difficult to get the FM radio function operational. The question is if it's possible to somehow integrate it into the firmware. Moreover, it would be great if there could be found a way to transfer the measurements via BT to a PC for data logging. Either there's a wide field open for hacking or maybe the manufacturer just left some options for an up-rated model...bad luck for the early adopters 


Edit: I attached some PNGs of a clearer version of the schematic that I found in a different place.
Edit2: Added two photos of the main PCB

[devan]

I opened mine up to see where pin 20 (P1.4) for the serial output goes. Following the trace and probing, it's connected to R29, which sadly is a 100k pullup resistor, not a series resistor to the unpopulated Q16.
There is still a via, but I'm not quite adventurous enough to unscrew all of the front panel PCBs to see what's on the other side, so I'll hold off a bit on finding out where else it's connected to.

R29 is not a great place to solder to, but it beats soldering scraping soldermask or soldering directly to the QFP leads, so that seems like a viable path for getting at the serial output.

If I can track down my clip leads, I plan to probe the EEPROM to see if I can passively extract the configuration/calibration using sigrok. If I can do that, then I'll see if I can reconfigure it to enable the serial output feature ala Kerry Wong.

[devan]

Well, I probed the EEPROM, dumped the contents, disabled the write protect, and updated the configuration byte at 0xFA from its initial value of 0x00 to 0x02.

For reference, I added external pullup resistors to the I2C bus while holding the multimeter chip in reset by grounding the reset test point. When writing, I also added a pulldown resistor to ground the active-high write-protect pin.

Here's my original config dump:

Code: [Select]

FF FF FF FF FF FF FF FF FF 52 00 FA 00 00 BE 03
10 17 20 4E 52 03 6E 50 64 4B 3C 3C 0A FF 40 FF
F3 98 55 83 64 00 96 00 00 80 00 80 BB 7E 0F 8C
4E 02 09 18 01 09 50 01 0B B5 17 0A 58 FF 09 00
00 01 00 01 00 07 98 00 64 00 64 00 64 00 00 00
00 80 BE 7E 21 8C 00 80 00 80 00 80 00 80 00 80
86 7F 04 80 0A 00 91 2A 00 00 00 00 00 00 00 00
80 81 00 80 35 82 E0 7C 18 01 00 00 00 00 00 00
00 00 00 00 00 16 00 10 00 0C 00 07 17 01 12 03
00 00 00 00 00 00 00 11 00 0D 00 0A 00 02 00 04
00 00 00 00 00 00 00 00 00 00 00 0B 00 13 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 15 00 00
0D 00 02 10 00 00 00 00 00 00 00 00 20 00 03 10
2C 80 00 80 00 80 00 80 00 80 03 05 0D 00 02 20
00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80
00 80 FF FF FF FF FF FF 5A 0F 00 00 00 00 00 00
Unfortunately even after updating the config at address 0xFA, it doesn't seem to output anything on PT1.4 (as probed on the not-vcc-side of R29). I'm not entirely surprised, since I never observed the multimeter reading from address 0xFA.

Here's a dump of the read operations I saw (this includes turning it on, pushing a bunch of front-panel buttons, then hard power cycling it):

Code: [Select]

(addr=F8,  2 bytes): 5A 0F
(addr=12,  2 bytes): 20 4E
(addr=33, 12 bytes): 18 01 09 50 01 0B B5 17 0A 58 FF 09
(addr=20,  4 bytes): F3 98 55 83
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=50,  6 bytes): 00 80 BE 7E 21 8C
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=EA,  2 bytes): 00 80
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=EA,  2 bytes): 00 80
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=60,  8 bytes): 86 7F 04 80 0A 00 91 2A
(addr=70, 12 bytes): 80 81 00 80 35 82 E0 7C 18 01 00 00
(addr=D0,  2 bytes): 2C 80
(addr=D2,  2 bytes): 00 80
(addr=60,  2 bytes): 86 7F
(addr=D4,  2 bytes): 00 80
(addr=D6,  2 bytes): 00 80
(addr=60,  8 bytes): 86 7F 04 80 0A 00 91 2A
(addr=70, 12 bytes): 80 81 00 80 35 82 E0 7C 18 01 00 00
(addr=60,  8 bytes): 86 7F 04 80 0A 00 91 2A
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=12,  2 bytes): 20 4E
(addr=33, 12 bytes): 18 01 09 50 01 0B B5 17 0A 58 FF 09
(addr=20,  4 bytes): F3 98 55 83
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=50,  6 bytes): 00 80 BE 7E 21 8C
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=EA,  2 bytes): 00 80
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=12,  2 bytes): 20 4E
(addr=33, 12 bytes): 18 01 09 50 01 0B B5 17 0A 58 FF 09
(addr=20,  4 bytes): F3 98 55 83
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=50,  6 bytes): 00 80 BE 7E 21 8C
(addr=40, 14 bytes): 00 01 00 01 00 07 98 00 64 00 64 00 64 00
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C
(addr=EA,  2 bytes): 00 80
(addr=2A,  6 bytes): 00 80 BB 7E 0F 8C

I noticed that it does read from address 0x33 and 0x72, which are not documented in the datasheet that Kerry Wong translated. Perhaps there's some new functionality, or the meter is simply storing additional configuration in unused space in the EEPROM.

It's also possible that I need to press a different button to actually trigger the check for the REL / RS232 functionality, since a lot of config seems to be read on-the-fly.

[Andrew_Debbie]

Mine arrived today.    It is on CNY sale at Bangood for about $61 US.   I couldn't resist the absurdity.

It needs to be plugged into a charger to start the first time, even with fully charged batteries.   After that it is portable.

The power switch is in the back   
No CAT rating anywhere. 

So far it is a good bench DMM  for the price.     I've only been using it for about 10 minutes. 

2.5000VDC reference  read as 2.500V


The BT speakers are a complete fail.   The audio is unlistenable.  Dropouts and glitches every few seconds.     
I suppose I can hope for a firmware update.   Not holding my breath.

Update:  Upgrading my Nokia 7 Plus from Android Pie to Android 10 fixed the bluetooth audio issue.   

Clock works and is easy to set.
Thermometer appears to be working.  I'll check accuracy next week.

[flash2b]

I did not have problems with the BT audio. I have not encountered glitches or dropouts even when my phone was some meters away from the DMM. The sound is actually pretty good and its stereo unlike a lot of other BT speakers and there is also some bass to it. The AN888S is BT 5.0 same as my Galaxy S8.

[TurboTom]

I did not have problems with the BT audio. I have not encountered glitches or dropouts even when my phone was some meters away from the DMM. The sound is actually pretty good and its stereo unlike a lot of other BT speakers and there is also some bass to it. The AN888S is BT 5.0 same as my Galaxy S8.

Same observation with mine. Phone is a (pretty much beaten up... ) Elephone P6. No dropouts and quite acceptable sound. The speaker may underemphasize the lower mids a little but that can be compensated for with the equalizer function of the player. Since I'll anyway never use the meter in a remote location, it will stay connected to an USB wall wart so the LiIon battery's sole purpose will be to buffer the RTC in case mains power drops out (almost unheard of in my part of the woods...). I guess I could as well leave them out. Otherwise, it's quite an accurate entry level bench meter with a few additional gimmicks.

[Andrew_Debbie]

Time to troubleshoot.

I tested with a Nokia 7 Plus running Android 9 (Pie).  Pretty much plain vanilla android with no mods or developer settings.  The phone is supposed to be BlueTooth 5.   Audio from my phone worked with several cars and a Canton sound bar. 

I updated the phone to Android 10 yesterday.    I'll try again and also try with Debbie's iPhone 7.

[Andrew_Debbie]

Either there's a wide field open for hacking or maybe the manufacturer just left some options for an up-rated model...bad luck for the early adopters 

The outer box has check boxes for two versions.  One with an app and one without.    I haven't seen the app version for sale anywhere.    Marketing must be expecting an up-rated model at some point.

[floobydust]

They say it has BT serial capability, pin 20 goes to R29 and a via. "Try to modify data at address 0xFA; to 0xCE, to start uart and send ttl data"
"The APP is called Dianniu, but this first one is a try. It is released in advance, the software is not perfect, and it is estimated that it can be upgraded in the future. Multiple Bluetooth meters can be jointly tested, remotely operated, etc." quote from https://www.mydigit.cn/forum.php?mod=viewthread&tid=102970 there is a WeChat qcode.

From the review:
ZT-5566 Bluetooth speaker desktop digital multimeter is an automatic range multifunctional digital multimeter with 9999 counts. The meter is powered by lithium battery, true RMS measurement, LCD display, backlight brightness is adjustable, and it also has clock, alarm clock, Bluetooth audio, ambient temperature display function. See the disassembly: https://www.mydigit.cn/forum.php?mod=viewthread&tid=101189
The current is 30uA after shutdown, it is estimated to maintain the clock supply, and the switch will not affect the time; the current is 71mA after startup, and 52mA after Bluetooth is connected to the device; the screen brightness is adjusted six levels ---: level 1 (51mA backlight off) level 2 (55mA ) Level 3 (63mA) Level 4 (71mA) Level 5 (81mA) Level 6 (102mA), the default brightness at power-on is Level 4, the above is the test of the Bluetooth unconnected device; the current of the music is dynamically changed, and the maximum volume current is 122mA; When the button is not operated for 15 minutes, it automatically enters the standby mode (47mA). At this time, the main display shows time, and the secondary display shows information such as ambient temperature and battery power. If Bluetooth has been connected before, you can continue to connect. If you quit the connection or did not connect before, you cannot connect again.
Open circuit output voltage is 3.24V, overflow voltage is 3.000V, drive current is 1.75mA; resistance function: AUTO open circuit voltage is 0.5V, manual kΩ-Ω open circuit voltage is 0.9-1.0V, short-circuit current is 0.3uA to 422uA, the measurement speed is average; The meter has continuous beeps (DC gear cycle 5s, AC gear cycle 8s) in the current gear state."

[devan]

I installed the Android test app from the QR code on my throwaway test phone. It did not detect my multimeter during scanning. It also doesn't show up at all in my BLE scanner app, so I'm inclined to believe that the non-app version of the multimeter that is currently available for sale is Bluetooth classic only.

I think unless someone happens to know how to modify the OTP memory on the DTM0660L, anyone interested in getting data from the meter will have to wait for the app-enabled model.

[Andrew_Debbie]

Upgrading my phone to Android 10 fixed the bluetooth audio issue.     

Now that it works, sound quality is about what I expected.    Not great but ok for casual listening.   The internal speakers in my 27" iMac  sound better.     The Apple mids and highs are clearer.      The AN-888S has more mid-bass but it sounds boomy and exaggerated.   Apple sounds more natural, but lacking any lows.



The manual advises against listening to music when making mV measurements.  I haven't done any tests, but will avoid listening to music when making critical measurements.   On the plus side the speaker is stereo and there are no annoying rattles.

The AN-888 goes into sleep mode after a period of non-use.   It beeps a few times, then the main display changes to time and the smaller display changes to temperature.   BT audio works when the meter is in sleep mode.

[Fungus]

Gotta get one for the living room... it's really stylish and you never know when you might need a quick capacitance measurement!

[ResistorRob]

I got mine yesterday. The bluetooth audio worked perfectly and the voltage had zero drift at zero volts, so I haven't had any problems other people have experienced. I might buy a second one to try hacking, because I don't want to brick my only one. I love the color! It looks better in person than in the photos. The red looks just like the Craftsman reboot red... very vibrant.  In my humble opinion this is by far the best desktop dmm under $100 anywhere on earth. Now I just need to get a new oscilloscope, lol.

[Fungus]

...has more mid-bass but it sounds boomy and exaggerated.

So ... just like every piece of consumer audio gear ever made since 1983. 

[neo2001]

I'm currently thinking about a way to get the or a power switch to the front. Unfortunately the whole front is covered by PCBs in one way or another. Thought of putting it on top, but there is only space for switches I wouldn't trust to work for very long. The only thing easy to do is putting one on the top of the backside instead having to reach down. But that doesn't really seems worth the effort. Well, I could throw out the speaker part... not gonna use it anyway...

I added some more pictures of the PCB in the back (mostly battery protection and balancing) and the speaker box:
https://imgur.com/a/3WcAQlb

EDIT: If I remove the two 4 Ohm speakers (the black box) the 4-pin header on the PCB will stay open/empty. Could this be an issue? Should I maybe put something else on there? If I find a better solution in the future, I still could put them back in.

[Andrew_Debbie]

I check-tested the temperature display against a UK made spirt in glass thermometer. 

Thermometer reads 21.5C  AN-888S 21C.      It works.

[Gandalf_Sr]

Wow Neo2001, looks like you could hide money inside the AN888S, it would probably take one of those $100,000 'bricks' of 1000 x $100 bills

[neo2001]

I found a way to place a small switch on the front. It turned out to be more space between PCB and the front panel then I was expecting. Still, the nameplate had to go -- a small price to pay for more convenience.

Even put a piece of aluminum in its place to make it look more classy. 

I was actually thinking of maybe designing and printing a new backside case since the device would become a lot smaller without the speaker box. But then again I would need some kind of stand to keep it stable and upright, which the big case already provides.

[uncle_sem]

banggood says AN888S has 19999 counts. but it has dtm0660l chip. how is it possible?!

[TurboTom]

As per the (translated) datasheet of the DTM0660, this "Multimeter Microcontroller" contains a 14 bit ADC, running at > 12kSa/s. This easily permits some averaging to increase the effective resolution. Since the DTM0660 only provides outputs for up to four LCD digits, the internal LCD driver isn't used. Instead, the display data is serially transferred to a separate LCD driver chip (of which are two present in the AN-888S, one for the meter display and another for the clock/temp display). Since the DTM0660 is basically just a microcontroller, it can be programmed to provide 4.5 digits resolution even though it cannot directly display it. In other, budgetary (hand-held) multimeters, the engineers have chosen the same solution with the DTM0660.
I guess that this chipset is just so inexpensive that it makes sense for the manufacturers to use it that way instead a more sophisticated single-chip solution.

[Andrew_Debbie]

They must be doing something-- After all 14-bit is  0 to 16,383  or about +/- 8191    Even 9999 count is out of range.

I wonder if there is some sort of pre-scaler along with signal averaging.         Whatever they did, it appears to work.