‘nuther new something in town …you can safely ignore it!

AI Thinker have obviously been listening …but the question is, to whom.  They’ve just come up with something which they’re calling the “ESP8266 Black board T5” (their capitalization, not mine).  It looks really interesting at first glance.

ESP13/WROOM-02 AI Thinker board, with battery box
AI Thinker “Black board T5” development board with attached battery box

[Update:-  I ended up reworking this board to make it somewhat functional.  If you’re comfortable with a soldering iron, you might be interested in these notes]

There’s a relay and a couple of screw-down connectors at one side of the board and what’s obviously one of the older  (blue) DHT11 temperature/humidity sensors on another side, sitting next to an ESP13/WROOM-02 module.  Between the relay and the DHT11 is a barrel-connector for DC input, but the unit also comes with a 3-cell (AA size) battery box attached via short flying leads (the board itself is just a little bigger than the battery box).  There’s a beeper on the board and there are three LEDs arranged in a vaguely spoke (as in bicycle wheel) shape.  In addition, there are two mini “tact” switches, a couple of jumpers, a slide-type on/off switch and, sitting like a spider in the middle of its web, a mysterious, 32-pin, QFP package chip.  Etched along the edge of the board is “ESP822_IOT_DEMO” (sic) and also “AI-CLOUD INSIDE”.

As usual with the on-line auction site vendors, there’s b’grall useful information on any of the pages which I could find (and as the auction sites advertise it as an “ESP8266 Serial Development Board” it’s also next to impossible to find any useful information on the web, either).  Anyway, just looking at the board I thought it had to be worth the $10 asking price, just in parts alone.  With a bit of luck, the mystery chip might turn out to be an I2C expander or something equally useful.  Throwing caution to the winds (poor old Caution!), I added a single unit (Caution must have crawled back home again while I was surfing dBay) to the next order I made for other odds n’ends.

Tum-de-dum-de-do.  Wait for a couple of weeks.  Odds n’ends arrive, along with da’ board.

AI Thinker
AI Thinker “ESP8266 Black board T5”, with red LED visible just to the left of centre.

Hmmm…  Don’t recognize the number on the top of the mystery chip.  Never mind, throw in some batteries and slide the switch to “On”.  A red LED (which I hadn’t noticed in the pictures) lights up and, after a slight delay, the board starts to emit an annoying “Do something within the next few seconds, or I’ll explode” kinda’ beep.  I press one of the buttons.  It still beeps.  I press the other button.  It still beeps.  I switch it off, hold down one of the buttons and switch it back on.  It starts to beep again.  Same procedure, but other button.  Ahah!  a single beep and then blessed silence …for about a second, then it starts to beep again.  I rip the batteries out and throw the whole thing in a drawer (I was sorely tempted to throw it on the floor and stamp on it, but I thought I might damage the floor).

Back to the web (as there was b’grall documentation in the package, of course) and I resort to a Oogleg image search.  Oogleg’s image processing may be wonderful, but it seems to think that this PCB is a dead-ringer for all sorts of weird and wonderful stuff on the web that just happens to have a black PCB.  I finally find a link to AI Thinker’s forum and a thread which has some links to documents (Yay!), one of which seems to be an English PDF (double Yay!).

My yaying turns out to be a little premature.  The English documentation is limited to the schematic and it’s a fairly useless one, at that.  Many of the components evident on the board aren’t present on the schematic at all, labelling is haphazard, parts are wrongly identified (the 32-pin QFP is labelled as an STC15L2K16S on the schematic, but the part on the board is an STC15L2K32S2 [see below], the sensor is identified as a DH11, but the part on the board is definitely a DHT11) and plugs, sockets and jumper blocks are all depicted as unidentified rectangles.  One thing that does stand out immediately though, is that most of the GPIO pins on the ESP8266 are unconnected.  Uh-oh!

T5 Schematic
Original Schematic

A P-Channel MOSFET (top R/H corner of the schematic) gives another clue to what’s going on here.  The drive signal is labelled “WIFI_VCC”.  It’s a supply-side switch for the ESP8266 power.  The board is battery powered and it looks as though the ESP8266 is only powered up when a network connection is needed (and I recognized this simply because I’m doing the same thing with one of my ESP8266 projects, but using a DS3231 RTC module to drive the power switch).

So, it turns out that AI Thinker have produced a board which has a “master” microcontroller and is using the ESP8266 simply as a network interface.

Next to the on/off slide switch there’s a three-pin connector (barely visible in the photo above – it’s slightly above and to the left of the DHT11) with the silkscreen label “R-G-T”, which appears to be the serial port for the microcontroller (not for the ESP8266).  I pulled the unit out of the drawer again just long enough to connect up the pins and go through the press-beep-disconnect routine a few more times at various baud rates.  I didn’t ever get any indication of any output at all in the terminal window.  Zilch!  Nada!  Nutt’n!  At the same time I fired up a WiFi scan on one of my access points.  I could quite easily see my neighbours’ access points going up and down, but no indication at all that the ESP-13 on the board was ever powered-up.  Back in the drawer wi’thu useless burger!

I might possibly drag the thing out again and have a poke around with a multimeter, but not before I’ve de-soldered that bloody annoying beeper.

The microcontroller chip on the AI Thinker
The microcontroller chip on the AI Thinker “Black board T5”

As far as I can tell from the scant information available for this microcontroller part number available on the web, the chip is an 8051 derivative, with 32K of onboard flash memory.  I haven’t used an 8051 chip in twenty years and, although I’m sure there are some folks out there who will be positively salivating at the thought of an 8051 paired with an ESP8266, there will most certainly be many thousands more who will be scratching their heads and saying “WTF?”.  I’m not (and probably never will be) an AVR/Atmel kinda’ guy, but why AI Thinker would AI Think it a good idea to produce a board for the hobby market with such an odd-ball chip is beyond me.  If they’d dropped in an ATtiny85, a Propeller, an MPS430, a PIC18F/24F, or just about any low-end ARM chip they would have had the (ESP8266) world beating that proverbial path to their door.  As it is, they’re destined to get a big, red “FAIL” stamp splattered across their collective foreheads.  Anyway, if you’re at all interested, I finally found the data sheet for the chip on STC’s web site (no thanks to their total lack of indexing or search function and the quiet inclusion in one data-sheet — with a single processor ID as the only title —  of 18 different chips).  The highlights are, yes 8051 based, 32KB of flash, 2KB of SRAM,  29KB(Eh?!?) of EEPROM, 2 x UART, 3 x PWM, internal clock and 8-channel, 10-bit A-to-D.  If all of that lights your fire, then this is the board for you (and I’ll sell it to you …cheap!).

Hold on just a second; I need to go and add a “Double Duh!” category for this one.

Update – In an effort to introduce some semblance of balance into this post (and especially to note that I’m not, generally “anti” AI-Thinker), I’d like to point you at a couple of articles on one of their other boards, which actually is something of a bargain!  Just about the only thing it has in common with the “T5” is a long and overly complicated name, but you should definitely keep an eye open for the ESP12-based “Yellow Development Board”.  Apart from anything else, it has lots of nice flashing LEDs and you don’t need to resolder anything to get them working.

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10 thoughts on “‘nuther new something in town …you can safely ignore it!

    • Mihai,

      I haven’t got it to work with anything at all. I even tried setting up an access point with the magic “SSID<!-SL-!>PASSWD” SSID, but no joy. Unless some kind commenter comes along with a tried and trusted method, this HOJ* is going to be broken down for parts in the very near future.

      -John-

      * Heap Of Junk

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  1. I gave up trying to use this as is, there’s just no support.
    But you can still use it.
    I de-soldered the beeper, this is a must as it will drive you nuts very quickly.
    Unplug the 2 jumpers that connect the comm lines of the ESP to the other microcontroller.
    Then you have 4 nice pins gpio_0, tx, gnd and rx that you can use in the usual way with a USB TTL adapter. I re-flashed the firmware and soldered a wire from the 3rd pin of the ESP board to give me a 2nd IO to play with which I connected to the DHT11 (also cut free from the board).
    So basically ignore the main board, see it as a power supply with a nice on/off switch to host your ESP.

    Cheers
    Frankie

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    • Frankie,

      Yup, that’s definitely the way to go. I already took the QFP off the board (tip:- use an box-cutter/craft-knife to cut through the pin leads to get the chip off and then it’s easy to lift the legs off the PCB with a hot iron afterwards). I haven’t yet got around to reworking the board to add connections from the ESP8266 to the DHT11 and LED drivers, though (but the satisfaction of destroying the “beep machine” was immense). 🙂

      Update –I’ve posted another couple of pages with some simple instructions on how to hack this board into something usable (as in, just using the ESP8266). Check for the articles titled “Reworking the AI Thinker T5 board”. It ain’t pretty, but it works!

      -John-

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  2. I translated the Chinese tutorial and found the following:

    This device is meant only to be used as an IoT demo between smartphone and Blackboard. First, you need to download the smartphone app (no idea which O/S) from http://t.cn/RLxuyfo This is the first option on the page. After installing 3 AA batteries and keeping the power switch off, you need to press and hold K2 while turning on the power. Once the beeping starts, you can let go of K2. It is now waiting for the smartlink configuration. Next, the app needs to be opened on you smartphone and you need to connect to your router by clicking on “smartlink”, putting in your password, and then confirming. The buzzer should stop beeping, provided it has the correct MAC address, etc. This may involve some of the other buttons as I can’t read Chinese. I believe there are a number of items the user needs to set, like name, password, phone number, email, etc. in order to register the device. There is a “scan” option to automatically obtain these, but not having tried it yet, I don’t know how well this works. The documentation talks about sweeping from 00 to 255 IP addresses and porting the device’s own device ID and password back to the APP. Once successfully connected, the APP allows the user to access the LEDs using PWM sliders. It didn’t mention if you can also access the relay or humidity/temperature sensor.

    Again, this device is just intended to be an IoT demo. It does use an STC chip (fast version of a 8051 device) as the main controller and the 8266 as the WIFI transceiver.

    If AI Thinker is interested in selling more of these devices outside of China, perhaps they might think of parallel APPs and documentation in English. I was fortunate enough to get a reply from the online supplier’s technical staff that led me to the Chinese website. Unfortunately, my Chinese is only good enough to understand Pinyin.

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    • John,

      I don’t have one of these boards (yet), but the ESP module is removable and can be programmed using the end connector (opposite the antenna end). It does look as though the board has a USB<->TTL converter chip on it though, so as far as I can see you’d be connecting directly to the ESP when you plug into the USB connector.

      This looks like a better board than the T5 (it is slightly more expensive), but look out for the area around the relay. As with the T5, there don’t seem to be any cutouts/slots in the PCB isolating mains voltage from the low voltage side and in this case you’re plugging in another device which may well be connected to AC mains, too (via the USB). I can’t find any pictures showing the bottom side of this board, so I have no idea what the track layout looks like. The best I can say is just “Be careful!”.

      -John-

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