ESP8266 Community Forum

I have a new module that I developed that I'd like to share but before I produce it I'd like to get some feedback and see if there is any interest in it.

The module is the same size as the NodeMCU module and shares many of the same pins. It's not menat so much for development as it is for deployment. I say that because it doesn't have a USB to TTL converter or a reset button. What it does do is this:

• Uses the TI BQ25505 Energy Haversting chip. This chip allows energy havesting down to 100mV input and has control for battery charging.
• It uses the TI TPS63011 Buck/Boost regulator which allows the voltage to be raised or lowered to provide power to the ESP module. This level can be switched at 2.8V or 3.3V.
• Because I had room I added a TI HDC1000 temperature and humidity chip.

The module has 3 connectors to plug in a solar panel, a Li-ion battery, and a backup battery. If there is enough energy the solar panel will charge the Li-Ion battery. If there is an extended period of time that elapses without charging, the circuit will automatically switch to the backup battery. The TPS63011 can boost from as low as 1.8V so 2 AA/AAA batteries can be used as backup. As long as sleep modes of the ESP are used you should never loose power. I've been testing this with different small solar panels with favorable results.

I've attached the schematic and board plots and will be releasing this as open source. I found only 1 minor design error on the prototype that I fixed with a jumper wire for the initial prototypes. Based on my findings of looking at the ESP-12 module I am considering changing this from accepting the ESP module to just placing the ESP8266EX chip directly onto this board.

Any thoughts or comments (both good or bad) would be greatly accepted.

Thanks,
George

Superb work. Excellent PCB layout, looks fantastic. Keep ESP12 one thinks.

Well done mate, put me down for a couple of these if price is good

Dans

I like the look of this too. Have you any idea what the cost will be?

I haven't gone through the BOM closely and haven't submitted quotes but general pricing on the main parts are:

• BQ25505 $3-$4
• TPS63011 $1.5-$2
• HDC1000 $2.5-$3.5
• CSD75208 $0.3-$0.5 (x2 pieces)
• The 2 inductors probably have a total cost of $0.5
• Miscellaneous passives and connectors, ~$0.5
• PCB, 4 layer ENIG, ~$1.50
• PCB assembly I need to check on.

So we have maybe $13 in material cost plus the ESP module. Assembly cost is going to be heavily factored on volume. Since the board is so small (~1.2" x 1.85") it will need to be panelized to keep the handling costs down. If demand is high enough I can try to squeeze some cost out of this but maybe we can get to ~$20 for a total solution which I think is quite good for something like this but no promises on cost until we know if I'm making 10, 100, or 1000 of these.