The blog of this week is completely about hardware.

PCBs arrived

Last  week the PCBs arrived. As a student 30 years ago I made my own PCBs with rub-down symbols and black tape on transparencies. The transparencies were transferred to photosensitive print material using an UV light-box whereafter the print material was etched using dirty toxic chemicals.

For this challenge it was the first time I made a PCB the clean way, by drawing in Eagle, and uploading the Gerber files to a  manufacturer.

I felt the same pride as 30 years ago when holding my own designed PCBs in my hands. And the result is beautiful as you can see on the images below.

As described in [Upcycle It] Nixie Display #5 - I2C Interface to display drivers to drive the 6 digits I use three identical circuits with a .PCF8574PCF8574 I/O extender. Advantage of this approach is that in stead of one big, I just need three small PCBs. Three (or more) smal PCBs appeared to be much cheaper to order than one big PCB.

The manufacturer minimal order quantity was five, so I expected to get two spares. As a surprise I got eleven in total.

If I can help one of the other challengers with one ore more of these PCBs, please let me know I would be happy to share them.

Here is a picture of the top and bottom of the PCB:

And here is a modified GerritCAD overview drawing:

Earlier this week I ordered the .PCF8574PCF8574 I/O extenders, a few 100n capacitors and jumpers for the address selection.

Workshopshed suggested to use flip pins (http://oshchip.org/products/Flip-Pins_Product.html) to connect the board to the 7490 sockets, although they look real suitable, unfortunately shipping time and costs were to high to the Netherlands.  I tried normal header pins, from which I have plenty in my junkbox. Luckily for the type of sockets used in the nixie counter, they fit reasonably well.

Just yesterday the other components arrived:

Soldering the components

Some pictures of the components that are soldered on the PCB:

Here a picture of the first board inserted in the first two 7490 counter sockets.

This finishes the blog of this week. We are halfway the challenge now, the first 5 weeks seem to have whizzed by, just 5 more to go. Here are roughly the steps I planned to take:

• Install a I2C Node-RED node, and test with my I/O board.
• When that works well, build the other two boards and make a software flow to display numbers on the nixie tubes.
• Implement a clock.
• Implement a connection to weather underground and display weather data
• Implement a software flow for displaying views an likes for one of my blog posts. (jasonwier92 pointed me to Node-RED: Lecture 6 – Intermediate flows – Node RED Programming Guide  which gives information on how to accomplish that, thanks!)
• Wrap up and summary.

Stay tuned!