Building a Pinewood Derby Timer: Setting up the LED displays

So one of the driving components (pun intended) of the derby timer is the LED displays. I went with the smaller ones from Adafruit, as we wouldn’t need a second power supply if we go this route, and I’d like to keep the unit as simple as possible.

You have to solder the displays to the backer board, and then you have to solder jumper pins across them to serialize each display. If you don’t do this part, your displays all show the same thing! I found that out the hard way! So be sure to solder those little jumpers. For convenience, the PDT website:

has a reference table:

PDT Lane # PDT Lane # I2C Address # Jumpers
A0 A1 A2
1 1 F 0
2 2 F 1 x
3 3 F 2 x
4 4 F 3 x x
5 1 B 4 x
6 2 B 5 x x
3 B 6 x x
4 B 7 x x x

Key: – = open, x = shorted; F = front, B = back

This is really handy. I really appreciate all the work they put into this, and it is fun to build along with a guide that covers about 95% of the process!

Linux – keep it simple.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s