These boards are being assembled in mid January 2019 and will be available soon. If you are interested, just email and I'll let you know the current status.

Clock Kit #1 $25 Price includes shipping in the US.

2 LED PCBs (hours and minutes) with SMD assembly complete. CPU board and female header strips (user solders in the connectors). User provides Nano board and COTS RTC with 6pin connector and standby battery.

Clock Kit #2 $35 Price includes shipping in the US.

2 LED PCBs (hours and minutes) with SMD assembly complete. CPU board and female header strips, RTC module, (user solders in the connectors). INCLUDES Nano and COTS RTC with 6pin connector and standby battery.

Programming the Nano

There are a few potential obstacles if you haven't been doing Arduino programming before. Here are a few tips for configuring the IDE:

• The Arduino uses a CH340 chip as the interface between USB and the CPU. You may not have previously installed this driver. If you need to get the driver, go to the Arduino.cc page and download from there.
• When selecting the device, be sure to select the Tools / Nano.
• There are options for the Tools / CPU, select Atmega328P (Old Bootloader)
• You also need to select the proper USB/serial port. If you open the Win Device Mgr /Ports, then plug in the USB cable to the Nano, you will port appear. Select this port in the IDE.

To program the RTC, you need to have the Nano plugged into the CPU board and also have the RTC plugged in (no battery yet).

After downloading the program, it will start automatically, detect that the RTC does not have a prior time setting and the Nano will set the RTC using the time from your computer.

The clock should then show the correct time. At this point, install the battery on the RTC.

Price $30 includes FREE US shipping.

Assembly Instructions

Digit Boards

The SMD components are already assembled and tested. You only need to add a few wires and connector pins.

The Minutes Digit Board needs to have a 3 and a 4 pin connector added to the Rear of the board near the 1 MIN digit. Looking at the LED side of the board, find the notation for TOP and MSD and LSD. LSD = Least Significant Digit which is the 1 Min (not the 10's of Min). Solder the 90 degree connectors to the rear of the board near the 1 Minute digit.

Jumpers need to be added to connect the Minutes board to the Hours board. On the rear of the boards, make short jumpers where the connectors are roughly adjacent. The 4 pin connector is power, the 3 pin is serial data. Be sure to have the board oriented the same (see TOP on the front side).

There are 2 long bars which hold the displays. Align the PCBs and screw them to the bars using the 3mm screws provided.

CPU Board

There are a few things to solder on the CPU board. Measure the female socket strip and cut it at the NEXT position in the strip. Install the female strip and solder it to the front of the PCB.

Install the pins/socket for the RTC. Some folks supply their own RTC and it may be male or female.

Install and 3 and 4 pin header for power and SPI to the display boards.

You can install wires from the provided terminals to an external source of +5v. This is NOT required until after the Nano has been programmed.

Install the RTC board but do NOT install the battery on the RTC. If you have it installed, remove it until later.

Completing the Clock

Install the 3 and 4 pin jumper cables from the CPU board to the Display board. OBSERVE THE PROPER POLARITY. OBSERVE THE PROPER POLARITY.

OBSERVE THE PROPER POLARITY.

OBSERVE THE PROPER POLARITY.

Programming the Nano

This is supposed to be an educational kit too! Part of your education is to learn how to program an Arduino Nano. There are lots of great online instructions, which unfortunately are indistinguishable from the crappy online instructions!

You need to select the proper port, device (Nano) and note that most Nano's come with what is referred to as the "OLD" or legacy bootloader. This depends a bit on what version of the Arduino IDE you are running.

The file you need to load is available on GitHub Github w0iy

more specifically https://github.com/w0iy/Arduino-LED-Clock

When you program the Nano, the Nano will get the time from your PC and magically program the RTC. After seeing the correct time on the display, plug in the RTC battery. Remove the programming cable from the Nano.

Apply power to the clock either via a +5v power supply or via a wall wart to the Nano. Both methods work just fine.

The clock keeps VERY accurate time (for a wall clock)

I got a nice "shadow box" at Michaels craft stores. It is deep enough and the clock looks great in it.

Write if you get stuck.