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By alex_g
#61180 Hi - I just got my second ESP8266 unit!
My first one was a NodeMCU 0.9 devkit, I suppose I'll write that up sometime, too.

I was attracted to this new "witty" devkit by its formfactor, for a number of reasons, and got one for £7 from a UK fleabay vendor. (Hope it's OK to post an image)

Since I want this for an application with motion sensors, I thought it would be a great idea to have a unit that is separable. That way, I could attach the USB-UART unit when I needed to program it, and remove it and attach my own concoction with the motion sensors when I wanted to operate it.

Further, I could use the USB "base" to program other ESP8266 modules in the future, without needing them to be full devkits, hence a lot cheaper. That's the theory, anyway. I should point out that this is my first time messing with microcontrollers, and at present I use Lua exclusively, though I know at some stage I'll have to migrate to C.

The following were my first impressions of the unit: The basic idea is pretty sound, but there are a number of flaws. The board comes with an LDR and an RGB LED already attached, which is fair enough - I suppose - for what is meant to be a "learner" product, but why on earth are they on the main board with the ESP? IMHO, they belong to the base/daughterboard, or whatever you call it... you should be able to detach them! They're not that useful after initially testing them. The LED, in particular, is just a cheap regular jobbie, NOT a WS2812, as I'd initially been led to believe (ho-hum), and frankly for the three GPIO pins it takes up, does not give much of a return. Putting all three LEDs on at full strength does not resemble white light, and I think the red one is somewhat weaker. You're probably better of just using it as 3 separate LEDs. I didn't think too much of its response to pwm, either, the range seems very limited.

Now, the unit does not have as many pins exposed as a normal devkit, so I thought, well maybe some pins got taken up by the LED; you could always somehow reclaim them if need be, with some nifty desoldering. Not so! three of the exposed pins, GPIO 12, 13 and 15 are also the LED ones. You're not left with much, GPIOs 2, 4, 5 and 14, I think. Trying to use analog input with the LDR will probably give rise to parallel resistance issues, too. OK, enough of that.

The board itself:- Why, after so many complaints about the width of devkit 0.9, and its not fitting easily on a standard breadboard, is this unit the same width? There's absolutely no need for it, it seems that the tracks have been stretched out "just because". OK, most users might not separate it for use on a breadboard, but still....

Switch positions. 3 buttons, one which brings GPIO4 low, a reset, and a flash. Two on the daughterboard, one on the mainboard. Can you guess which? If you think the reset is on the main board, you are wrong! That's GPIO4. Should have been the other way round, if you ask me. Plus the mainboard switch is a bit too proud and won't let the unit sit nicely on a breadboard.

I did, however, like that there is a micro-USB on each board, so you can still use the top one for powering, even without data. Useful, that's more like how they should be thinking.

The board was not pre-flashed, but it flashed just fine with esptool and the nice floating point firmware. I'm still waiting on the motion sensors, they coming over from the Orient.

In short, I am happy wit the unit, it will probably do what I wanted, but I admit I'd been hoping for something a bit classier. If it was a first board I'd probably have been disappointed and a devkit 1.0 (or even 0.9) are better options, I think, and cheaper, or much cheaper, in the case of the 0.9. For someone that wants this form factor though, this is OK, with some nice touches.

If I were to redesign it, I would:
Put toy peripherals (LEDs, LDRs, button switches) on the daughter board. Put the reset button on the main board (sheesh, guys). Make it narrower to fit nicely on a standard breadboard. Break out more pins.

Hope this is of some use to someone - cheers!