README

Injection molder digital control 
Columbia Gadget Works (2015)

This is a control system for a hobby injection molder as described in "Secrets of Building a Plastic Injection Molding Machine" by Vincent R. Gingery.

In the book, he uses a simple thermostat to control a heater element.  We wanted to try something slightly more sophisticated so we built this.

The control is housed in a small project box.  It consists of an arduino Nano on a custom board and connected to:

Two tact switches on D11 and D12 for up/down control of the temperature set point.

A Sparkfun 7-segment serial lcd display (https://www.sparkfun.com/products/11440)  The display shows a:nnn for the actual temperature and p:nnn for the setpoint.

A 10k thermister for measuring temperature of the heater block.

A Sparkfun beefcake relay control kit. (https://www.sparkfun.com/products/11042)

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Status:  
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It works but the interface isn't very responsive.

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TODO:  
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Improve the loop that detects button pushes.  
Allow push/hold for inputing the temperature.

Improve the loop that controls temperature.  PID?