Impact of global semiconductor shortage
June 18, 2021 2 Comments
As many already have noticed, there is a global semiconductor shortage. Many common integrated circuits such as the ATMEGA328P-AU processor featured on most of my SDI-12 USB adapters are simply out of stock for the foreseeable future or until later 2022.
As you can see, this is going to be a problem for many businesses big and small, including my line of SDI-12 USB adapters. Luckily I grabbed enough parts last year so I still have over 200 of them that will last for a short while before I run out.
Processors (200), USB chips (200), and 100 blank boards (boards can be reordered quickly) are photographed here. Hope this lasts for a while. If you are doing your own projects, unfortunately you won’t be able to purchase ATMEGA328P-AU or ATMEGA32U4-MU etc. until they are back in stock. Try the DIP version of 328P. They are still in stock.
As a response, I will temporarily focus on only producing the basic SDI-12 USB adapter and stop producing the SDI-12 USB + Analog adapter (red) that requires a processor. You CAN still get the hi-res analog features with a basic SDI-12 USB adapter and an analog input extension board. The combined cost is the same as the red adapter.
I can still produce the SDI-12 USB + GPS adapter although it is on low demand. If “worse comes to worse” and I run out before I can get restocked, I have over 100 ATMEGA1284P-AU processors that can be used to produce the SDI-12 USB + GPS adapter, just that I won’t attach any GPS and will sell those as basic SDI-12 adapters without extension ports. Or maybe I will redesign it to have an extension port.
Hi can I use sdi 12 USB adaptor to connect some meter group teros 12 sensor for data logging and to control some 24v control valves using rasberry pi? I would like to do a diy but can’t find much info on how to.
I would use a single SDI-12 USB adapter that has four SDI-12 connectors for up to 4 sensors easily. Make sure if you order teros 12 sensors. They allow supply power between 4V and 15V so you can power them with the USB power. The power switch jumper will just stay at the default 5V location. Then if you need to switch a 24V valve, you can use a digital pin on raspberry pi and a relay circuit. The relay must have some transistor and snubber diode to prevent inductive current that can damage the pin. I suggest instead of using a pin on raspberry pi to control the valve, you could use a cheap arduino and write a very simple code to say turn on the valve if it receives a “1” in serial port and turn off the valve if it receives a “0”. This makes it totally possible to develop the system on a PC, where you have everything handy and fast running, and then deploy to a raspberry pi.
Something like this will do:
https://www.amazon.com/HiLetgo-Channel-Module-Isolation-Support/dp/B00LW2H5GC/
https://www.amazon.com/ELEGOO-Arduino-ATmega328P-Without-Compatible/dp/B0713XK923/
They don’t seem to have single arduino nano for sale, too cheap I guess.
All of these can be placed inside of a box. I’ve used these knock-out series before. You can easily knock out a standard size hole for cable glands:
https://www.polycase.com/sk-series
I’ve used the SK-20. It has plenty of space for raspberry pi and a few other pieces and isn’t too bulky.
https://www.polycase.com/sk-20
Sorry this isn’t really a tutorial but it’s a start. I might do a tutorial later this month depending on time.