Sunday, February 26, 2017

Boards, boards, boards...but everything sure does look nice!

Things are moving along nicely for the energy monitor, and I've had a lot of fun designing boards for everything. As soon as I can get everything stuffed, I'll probably pull the old wireless sensors off the wall and put the new boxes in. 

The multivolt expansion boards came back from the manufacturer, and are ready to be stuffed. I have the jacks onboard, but nothing else - the LEDs, power conditioning, and input connectors will have to wait until I have more time.


Here's the family, in various states of assembly...

A couple of things to note, I decided to use some TO-92 heatsinks I'd collected over the years as a heat collector. That is, the DS18x20 in the upper left (sorry, black on black is hard to see...) now has a heatsink on it. Instead of getting rid of heat, it should get more surface area exposed to the air and hopefully provide a more accurate temperature measurement.

Second, and this is entirely my fault, the parts I ordered were not DS18S20, as claimed by the vendor, but DS18B20, which won't work at all if your device is expecting an older part. I ordered them, was told they were correct, and set them aside (without checking) until far too late. While some of the special-purpose embedded devices I use can't see them, I'm lucky that my chosen control board for this system has no problem with them. I learned my lesson: Always check your parts on arrival!

Last, but not least, as the loop expansion boards seem to work, I'm going to beef up the V+ tracks and send them off to have a production run made. I've seen a lot of board houses that can run 100 units for about $120, and use special color and masks to boot. Probably should order a  sample run first, though...

Tuesday, February 7, 2017

The one-wire-loop expansion board.

Yesterday evening, I received my generic expansion board (The One-Wire-Loop) back from OSHPark, and everything looks good. While I had originally planned this as a one-wire board, I figure it can work equally as well for any low-speed data, like serial or I2C.

The first example built up, sans the DS18X20 in the lower right corner, is ready to test in a live system.


With this board and the precision rectifier, I should be ready to start hooking up devices in their final configuration. Now, to just find the time...