Notes: Forgot to mention that I hot glued the top lid (original lid

for the 'speaker box'), on top of the boards. I had used the device with

the top uncovered for a month because I hoped I would find a better

choice but after getting tired of the wires detaching and worrying about

the sdcard slot getting wrecked I decided to commit to glueing the lid

on.

The boards are very robust, I dropped them in the snow a few times.

They would stop working but after drying off would function.

I didn't find the datasheet with the resistance values for other

values until after I glued the lid so will have to open it up again or

get into one of the switch lines and do resistor combinations... now

that I know more I think I should be able to control the mp3 player with

one analog output pin from the arduino for all the functions, since it

seems the pin 8 that all the switch resistors lead to detects voltage

levels from the voltage divider created when one of the switches goes to

ground.

The robot is using 4 lines right now for mp3 control. Would be cool

if I could free up 3 more but I don't remember if any of them are

occupying an analogue slot.

No power button! None needed. Pause and unpause via momentary switch.

The charger board can charge from micro usb or usb-c and will protect

your 18650 cell from running flat and damaging itself.

Check out my robots: https://bitchute.com/channel/mechatroniac

Post Apocalyptic Robotics Database Entry:

HH000000000

H Hybrid: Denotes some prepurchased or hard to find components

H Human use: For use by biological humans

Tools and supplies

multimeter - not strictly required but highly recommended

Soldering iron

solder(thinner solder wire works better for electronics)

wire stripper

hot glue gun

electric or duct tape

side cutters/cutting pliers/aircraft snips

Buy:

1s 18650 charger board

https://www.aliexpress.us/item/2251832744326141.html

GPD2846A TF Card MP3 Decoder Board 2W Amplifier

https://www.aliexpress.com/item/4000188516180.html

https://www.aliexpress.com/item/32968306923.html

Find or Buy:

short lengths of wire

4 ohm speaker (can be found in old tvs)

momentary switches(3) - can be found in vcrs, tvs, dvd

players...

18650 cell

3.5g weed jar or similar + lid

larger lid

(optional)

You should consider getting an arduino or a kit

Keyestudio Basic Starter Kit V2.0 With UNO R3 Board Or Mega 2560

R3 Board

https://www.aliexpress.com/item/1005004961819902.html

GPD2846A datasheet

https://pdf1.alldatasheet.com/datasheet-pdf/view/1132627/ETC2/GPD2846A.html

https://datasheetspdf.com/pdf-file/949393/Generalplus/GPD2846/1

Picture 1

Click the thumbnail to see

the full-sized image

Picture 2