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BOM Errata (read this if you ordered a PCB on Tindie)

A project log for The Open Book Feather

An open hardware reading device

joey castillojoey castillo 07/16/2020 at 15:150 Comments

Yesterday a GitHub user alerted me to a typo on the printed BOM included with the E-Book FeatherWing. It was minor (omitted a part that should have been there), but if you ordered the quantities listed, you would be one part short when assembling the board. 

This error got me worried about the Open Book BOM, so I did a check and found one typo there as well. Both errors are now fixed on the Kitspace BOM for the E-Book Wing and the Open Book, so if you haven't ordered parts yet, you can 1-click order there and be fine. But here are the two typos, so that you can work around them in your build:

The E-Book FeatherWing

The line for 10µF capacitors lists only one capacitor, C1. You actually need two 10µF capacitors, C1 and C2.

C1 is a decoupling capacitor for devices on the JST ports (say, if you plan to drive a high current device like a white LED off of one of the STEMMA ports). C2 is a decoupling capacitor for the SD card. If you already ordered parts and find yourself one short, you can omit C1 and put it on C2's footprint. If you haven't ordered parts yet, order two 10µF capacitors, and populate both footprints.

The Open Book

The line for the 0.47Ω resistor incorrectly lists its reference as R5. That line should in fact read R12. When assembling the Open Book, you should place the 0.47Ω resistor on the R12 footprint.

R5 is correctly listed in the previous BOM line; it's a 1KΩ resistor limiting current through the green "Battery Full" LED.

R12 is a 0.47Ω current sense resistor for the e-paper display's boost circuit. It is required for the e-paper display to function.

I'm really sorry about these typos, and I hope it hasn't hung anyone up in assembling their boards.

Both the Open Book PCB and the E-Book FeatherWing PCB — with corrected documentation packets — are available on Tindie, but I am currently not shipping orders. Still, you can sign up there to be notified when shipping resumes!

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