Simples :-)
Start with a keypad :-
Open it up...
There is not a lot of space...
(This had a proxy reader, which I removed)
We'll need a few parts, including a freshly milled PCB. All from GitHub.
No space for the spacer...
Fits nicely...
Not forgetting a wire link - sadly I could not manage a layout without this...
Add the RS485 convertor and power regulator and some wires, crop the leads nicely...
Looks tidy... (I then sprayed the bare copper with clear lacquer, by the way).
They keypad has handy 5V pads...
And the A/B wires...
And it fits in nicely...
Put back together...
And it works!
I have a couple of suggestions.
ReplyDelete1) The ESP8266 draws a spike of current when it is transmitting of around 300mA. A PP3 battery can supply in the region of 150mA. With a full battery it will tend to work but as the battery voltage drops the current drawn from the battery will increase and eventually the battery voltage will start dropping too low and the ESP8266 will become unstable when transmitting.
If you add a 10uF capacitor (a tantalum would be a good choice) close to the ESP-01 it should make it more reliable and allow the battery to be usable down to a lower voltage.
2) With wires soldered down through the PCB the sharp edges can cut the wires if there is vibration. You could solder them underneath and have a hole in the PCB for them to come back up through and this will also act as a strain releaf.
Not actually planning to run from a battery, but good tips, thanks.
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