2018-05-10 (Th) ModuKey

The third revision of boards arrived alongside surface-mount resistors. The resistors were inexpensive parts with the following specifications 1/4 Watt power, 10KΩ resistance, 1206 footprint. These specs were not vital. 1/8 watt would suffice. The resistance could be ±3KΩ. A 0805 size resistor would probably fit too.

IO expander chips were already stocked. No solder paste was available, so the pads were tinned before the chip was put in place and blasted by the hot-air soldering station. Resistors were installed by tinning one pad, pushing the resistor into place while heating the solder then soldering the final side. 1206 resistors were easy to install by hand with a fine-tip soldering iron.

Addresses were assigned by making solder bridges across the address pads, and a felt-tip marker was used to mark the boards. Since all the serial lines are essentially connected in parallel, the boards can be connected in any order, or even rearranged after programming, and the buttons will retain their functions. This address will be important when programming functions.

Boards with chips and resistors installed

The rest of the posts for this project have been arranged by date.

First time here?

Completed projects from year 1
Completed projects from year 2
Completed projects from year 3
Completed projects from year 4
Completed projects from year 5

Disclaimer for http://24hourengineer.blogspot.com/

This disclaimer must be intact and whole. This disclaimer must be included if a project is distributed.

All information in this blog, or linked by this blog, is not to be taken as advice or solicitation. Anyone attempting to replicate, in whole or in part, is responsible for the outcome and procedure. Any loss of functionality, money, property or similar, is the responsibility of those involved in the replication.

All digital communication regarding the email address 24hourengineer@gmail.com becomes the intellectual property of Brian McEvoy. Any information contained within these messages may be distributed or retained at the discretion of Brian McEvoy. Any email sent to this address, or any email account owned by  Brian McEvoy, cannot be used to claim property or assets.

Comments to the blog may be utilized or erased at the discretion of the owner. No one posting may claim property or assets based on their post.

This blog, including pictures and text, is copyright to Brian McEvoy.