I was working on a number of projects that used the ProMini as the microcontroller. I was irritated by the lack of shields specifically for the ProMini.

First, I designed a board that I called my ProMini Sheid Carrier which had a power supply, an RTC, some LEDS, a place to plug in one of those cheap, Chinese breadboard power supplies, and connectors for a regular UNO style shield.

(Click the pictures for a higher resolution version.)

What I really wanted, though, was shields designed specifically for the ProMini.

So…I designed them.

In the cover photo are (from left to right):

DS1307 Real Time Clock with Battery Backup DS3231 High Precision Real Time Clock with Battery Backup Dual FRAM (or other memory with the same pinout) Buzzer RS232 Transistor Driver Port D Screw Terminals Port B & C Screw Terminals I²C 1 Wire LCD with Contrast (ETTeam Connector) Blinky Lights

At first I made them stackable, like UNO shields…

but that looked stupid.

So I designed a ProMini Backplane board that would carry them.

The backplane includes 6 slots. The boards can go in any slot but the PSU slot has a couple of extra pins to bring down regulated 5V and 3.3V for the screw terminals and jumpers to select which regulated voltage goes to the Vcc line. The ProMini slot next to the PSU slot has a jumper to disconnect Vraw from the ProMini so it can be powered by the regulated supply voltage of your choice. The board also includes a 6-pin ICP slot and they can be daisy-chained together to add slots.

I had a lot of fun designing all of these boards and putting them together.

I put together these kits for my kids. They include one of each board, a breadboard, a USBasp, a programming cable, some Dupont wires, a 1602 LCD and LCD cable, and a little homemade button pad and strip of 8 LEDs with resistors.