In this article we guide you through an industrial grade shredder and/extrusion controller, housed in a standard control enclosure. We use a shredder & extrusion combo since it has mutual components. In later versions of the article, we focus on a shredder or extrusion only controller.

That are the features we’re looking for:

• direction control for the motor : forward/reverse
• auto-reverse using a hall and/or proximity sensor as rotary encoder (like on CNC/Lathe spindles)
• acoustic and visual alarm for errors
• extra safety features : hopper or enclose open 
• circuit breakers
• maximum safety & security, eligible for schools and subject to some certification 
• tbc ..

In this version, we’re using a VFD and an Arduino based micro-controller which enables us to control everything at low voltage. Another guide to archive the same without VFD may follow later in November.  

Control – Panel

1. VFD : we chose Omron for max. reliability and flexibility. This brand would allow also power profiles in later versions, perfect in situations using solar. It supports Modbus.
2. 3 Phase motor circuit breaker
3. Amp/Kwh metering. I am still thinking to read this meter for triggering alarms in case there is an energy budget
4. – 6 : breakers for all sub circuits
7. Power supply for digital / DC components
8. SSR relays for the heat-bands
9. terminal blocks (distribution for power and data cables)
10. the magic box, making it all happening. I am still undecided but it will be Arduino based, using screw shields and an LCD for low-level settings / adjustments like disabling/enabling features 

Front Panel
1. Emergency switch
2. Power on for shredder
3. Power on for extrusion
4. Direction switch for motor
5. Status light for errors (max. auto-reverse trials exceeded and jammed, over-heated, over-torque)
6. Status light : system ok and running
7. Reset button: this will reset the system (red?)
8. PID controllers
9. Key lock for the entire system, optional numeric keypad, voice or finger print and eye scanner (kidding)
10. Acoustic alarm

Auxiliary / Peripheral
1. proximity sensor(s), essentially to make auto-reverse happening but there are two more, one in the enclosure and one at the hopper. Possible more for other enclosures containing moving parts as couplings.
2. Another emergency switch near the hopper 
3. temperature sensor(s), one to avoid motor overheating, and one to read the ambient temperature (in cases like extreme summer and sun exposure)

It doesn’t look like but your are looking now at around 600 – 800 Euro in materials, 2 days work, and one-time 2600 Euro for QA reviews :-) I have no clear idea yet how the CE or self-certification certification process is but I assume it’s in the 5000 Euro range.

If I forgot anything or you can spot other safety improvements, let me know please.