Yet another offering from AI-Thinker

Well, like just about everyone else in the world, I’ve been waiting for the Middle Kingdom new year’s holiday to get itself over with so that we can get back to ordering stuff in the hope that it’ll turn up in just a couple of weeks, rather than a month or so.  Much to my surprise though, the postie dropped off a little package for me today which I had pretty much assumed hadn’t made it out of the starting gate before the beginning of the holiday.  My second surprise was that the boards in the packet actually worked, right off the bat, without the involvement of soldering iron, boot or hammer.  I was so shocked I had to sit down and settle my nerves with a little drink (luckily the teapot was already warmed, as we’re right out of Scotch).

I’d taken a chance and ordered another couple of AI-Thinker boards, working on the principal that nothing could be as abysmal as the initial experience of the “T5” and, as before, based on the fact that the cost of each board was significantly less that the cost of the components if I were to buy them separately.  These boards are generally referred to as the

Yellow Serial Development Board
AI-Thinker “Yellow Dev Board”

“Yellow Development Board” (or sometimes, “Plate”) and have been available for quite some time (longer than the “T5”, I think).  They come with an assortment of LEDs (most of them tiny little surface-mount parts, but also one ginormous, RGB, through-the-hole jobbie, too), a CDS light sensor (tacked onto the ADC pin), an on-board HT7333 low-quiescent-current voltage regulator, a battery box (3 x AA cells), a jumper to enable programming mode and an ESP8266-ESP12.  One of the neat points of this board is the fact that all  of the ESP8266 pins are available on header pins on the top side of the board and there’s also a separate programming header (which, unfortunately, seems to be incorrectly labelled on the silk screen, with the TX and RX pins reversed when compared to the ESP8266 header pins).

The board comes pre-loaded with a demo which does actually seem to work.  If you have an Android based phone or tablet you can download AI-Thinker’s app to control and mix the colour balance on the RGB LED and to switch the other LEDs on and off.  All very much better than the “T5”.  There are a couple of reviews out there already (here’s Marco’s short video review).  One of the better ones was written by Squix, way back in January of 2015 (I told you this one has been around for a while), including a very nice labelled photo which shows the correct pins on the programming header.

So, why the interest in an old board?  Well, first off, after my bashing of the newer “T5”, I wanted to be able to recommend an AI-Thinker board which is actually functional and good value.  This board is still readily available from lots of sellers and is a cheap way to get your hands on an ESP12 .  As it stands, it is a functional, nifty demonstration of what can be done with a single ESP8266 and a couple of AA batteries.  It is also readily reprogrammable via the 3-pin header to run your own firmware (how about a novelty night-light toy for a child …run a simple light display for a while, sleep for a random amount of time, display, sleep, display…).  Anyway, it seems as though the board would make an excellent platform for hacking into more useful devices, especially as all of the I/Os are split out already.  Adding a few sensors and MQTT functionality should be fairly easy …and that’s what I’ll get into next time.

Update:-  Just to show that you don’t need huge amounts of work to get a small project working …here’s one of these boards with an ENC28J60 module simply wirewrapped to the existing pins (8 connections in all), serving web pages, courtesy of Cicero and Sprite_tm.

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5 thoughts on “Yet another offering from AI-Thinker

  1. Hi,

    I’m searching for a scematic diagram of that board, because I want to replace the LDC with a thermistor and therefore have to find out the values of the voltage divider on the board.
    Do you have an idea where I can find that diagram?

    Thanks

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    • No idea, JD. I haven’t found one yet. However, looking at the board and using a multimeter to check I can see that there are two 1-meg (“105”) resistors in series between VCC and GND with the mid-point connected to the ADC pin. That means that there would be 1.65v on that pin (which is meant to be limited to 1v max), except that the LDR is connected in parallel across the bottom resistor (ie:- between the ADC pin and ground) and seeing that it has a much lower value (both in the light and in the dark) than the 1-meg, it keeps the voltage on the ADC pin to a safe level.

      -John-

      Like

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