There have been complaints that ESPboy1 is hard to build for beginners and of course that’s my fault, I got carried away with compactness and SMD.
But now I decided to go back to the source and finished a simplified circuit on large and cheap through-holes components.
Now you can buy all a few parts for less than $10 and even a kid can solder them.
It’s very hard to go wrong.
The compatibility to ESPboy1/ESPboy2 is 99.9% and an extension slot is provided.
So even on this simple device is available ESPboy AppStore, WebAppStore and in general all software and extension modules of the standard ESPboy.
Thanks to @MLXXXp for helping me design and the whole community for their support and inspiration
DIY you first own ESPboy!
Note that if you want to power the board using 3 NiMH rechargeable batteries (~3.6V total) or a 3.7V LiPo battery, instead of 3 Alkaline or Zinc-Carbon batteries (~4.5V total), you should replace diode D1 with just a wire jumper to provide the proper voltage on the expansion header’s VCC pin.
Thanks! Added note to PCB
Very good Roman!
This is too good for me to pass. I have to give It a try.
I wonder If It would be a good idea to use this little contraption or similar for the supply:
It can give 5V with one AAA or AA or two or three… With a lithium 3.7… anything!
You can try it and tell us about the result )
my goal was to use as few elements as possible with all the large components with mounting through holes.
but anyone can make their own circuit
If you supply power by putting a full 5V on the battery connections, it would be better to put two regular diodes in series for D1 instead of a single one.
Also, you should put the booster module after the power switch, so the booster isn’t receiving power even when the switch is off.
It’s good practice to have decoupling/bypass capacitors close to the power pins of the components on a PCB. The Wemos module will have it’s own capacitor(s) on board but it would be good to have one for the MCP23017 chip. I’ve added this capacitor. The capacitor should be a 0.1uF (or higher) ceramic.
My modifications can be found here:
Feel free to use or modify this version instead of the original.
In addition, I reversed the buzzer pins so that the “+” pin now goes to the V_BAT side of the circuit, which makes more sense to me but it won’t make a difference electrically.
I then got enthusiastic and made a large number of changes to the trace routing and widths, as well as a few changes to the silkscreens. However, other than the new capacitor, it should be identical to the original, electrically and for component placement.
NOTE that if there are any errors or problems with the original schematic or PCB then it’s very likely they exist in this version, as well.
Here are the details of what I’ve done:
On the schematic and PCB add a decoupling capacitor for the MCP23017.
On the schematic and PCB changed the buzzer polarity so plus (+) now goes to the V_BAT side.
Removed unused via in GND trace close to the BAT- pad.
Removed unused via in the D4_LED trace.
Made all trace vias have a 0.4mm hole and either 0.8mm or 1.0mm diameter.
Moved, rerouted and resized many traces to:
- Add more clearance from component pins.
- Add more clearance around board mounting holes.
- Move traces away from the edge of the board.
- Make thicknesses more consistent and in some cases wider for power traces.
Moved bottom silkscreen B5 and B7 expansion connector text, and reduced the size of and repositioned B6 and SC text due to interference with the new capacitor pads.
On top silkscreen changed text for the display from 1.44’ to 1.44" (feet to inches).
On top silkscreen changed position of text for the display to avoid printing on top of a new via.
On bottom silkscreen changed text “EXPANSION SLOT” to “EXPANSION CONNECTOR” and repositioned the text to avoid printing on top of new vias.
On bottom silkscreen for the text describing substituting a wire for the diode, changed the “I” in “If” to uppercase.
On both silkscreens moved “ESPboy” text up a little and changed the version to v2.1(MLXXXp)