Proportional Valve: L3 Prototype

This project is progressing well.  I have been seeking funding channels to get a bunch of pre-production ‘sweet-spot’ units built, along with microprocessor control boards in order to evaluate the ‘sweet spot’ controlling on boilers and heat pumps.

The second prototype using Omron SSRs failed dismally.  There appears to a problem with the internal snubber network not working with the motor ‘hold’ signal.  So back stepping fails.

A third stage prototype using my own design of opto-isolation and drive triacs is coming along well.  The circuit is designed, the PCB is laid out ready for small run production.  The parts are here to assemble a vero-board based prototype prior to ordering any PCBs.

I have also found a PCB manufacturer in the far east who can turn around small volumes of PCBs and ship them back to UK in around a week.  And at a sensible price, compared to Europe.  I would have liked to use a supplier more local, but a China manufacturer can make a batch of boards for the same price as a single board made in Europe, finances dictate otherwise.

The controller is designed and I’m pretty happy with it overall.  I need to tweak the connectors in both position and format and then I think it is there.  Wondering if the Arduino Nano, at its core, is large enough to handle the prototype data logging version of the software.  Program memory is going to to be an issue with libraries loaded for:

  • SD Memory card
  • Real Time Clock (RTC)
  • OLED Display
  • Bluetooth interface for SD downloads

All these libraries, along with normal operational code and data logging code is going to be a tight squeeze in the Nano.  So I’m currently considering making the controller board also support an ESP8266 based module too.  This would also provide a future upgrade path if needed.  And the ESP8266 would also provide for Access Point (AP) WiFi connections for data downloads and re-flashing of the program.  I’m not going down the Internet of Things (IoT) path, there is absolutely no point.