kiwigrinder

The datasheet for the MAX7219 shows that the minimum voltage is 4V. Running it from a 3.3V supply is not recommended.

Your circuit emulates a LM3914 chip which uses a linear resistor ladder where all resistor values are 1K ohms .The LM3915 chip uses a logarithmic resistor ladder where the values are 1K, 0.41K, 0.59K, 0.83K, 1.17K, 1.66K, 2.34K, 3.31K, 4.69K, 6.63K ohms. The LM3916 chip uses a VU scale and the resistor ladder values are 708, 1531, 923, 819, 1031, 1298, 769, 864, 970 and 1087 ohms.

Nice work. Do you have a template for the acrylic sheet?

Can you please provide the eagle files and the max7219 library that you used. Thankyou

The Electronic LED Hourglass uses STC15W201S microcontroller. This is basically an enhanced 8051 microcontroller which is a INTEL based design. PIC processors are from Microchip and use a completely different instruction set and architecture

I always drill my boards directly after the etch while the toner is still on. It is a lot easier to see the holes.Also once you clean off the toner, spray the copper side with PCB Lacquer otherwise overtime the copper will oxide and turn green.

Great looking animations. Pity you can't see them in real-time.Is there a reason to use the 4 neopixels?A single RGB LED should be able to the same job (you would need to paint the animation more times, but it should still look the same on time lapse camera). A single LED should be lighter and less taxing on the stepper motor that controls the arm.

Where is the fun in that? :-)