Hardware Question: Mega, stepper, relay, 4+ sensors

Development Boards Arduino
1

Hi all, I would appreciate some guidance on hardware setup for the following:

Background:

Automated table top plastic injection molding machine using the following (minimum) hardware components:

(4) pneumatic valves (relays)

(2-4) contact position sensors

(1) thermistor

(1) thermocouple

(1) stepper motor (connected to screw to feed plastic pellets into hot chamber)

Possible future additions:

(1) relay for small coolant pump control based on thermistor output.

My question is, I have been searching for available hardware and have pretty well settled on the Arduino Mega platform due to the number of I/O I will need. I believe I will need a relay shield, probably the 8 relay shield by sparkfun, a stepper motor driver, thermocouple amplifier?, and a sensor board?

While looking at some of the hardware components it seems some have stackable headers while others do not, I have not found a stepper motor controller with stackable headers. I was really hoping to keep the install clean as one unit and not have jumpers running to individual boards but is this a pipe dream?

Any recommendations on if I can actually use all of this hardware on one MEGA (with aux. Power supply) would be appreciated.

Thanks!

07

Ps. I’m a mechanical guy so if possible please dumb down the electrical jargon for me :smiley:

2

07gtimyfast:
Any recommendations on if I can actually use all of this hardware on one MEGA (with aux. Power supply) would be appreciated.

Links to the particular shields would be useful. For example I didn't find "the 8 relay shield by sparkfun". You might also prefer some electronic 'driver' vs a relay for those valves. Again more detail is needed.

Stackable headers can be added, a bigger concern would be which shield uses what pins. It’s not unusual to find 2 shields that want to use the same pins. You may find using a Breakout Board (BoB) is preferable to another stacked shield.

3

Mee_n_Mac:

07gtimyfast:
Any recommendations on if I can actually use all of this hardware on one MEGA (with aux. Power supply) would be appreciated.

Links to the particular shields would be useful. For example I didn't find "the 8 relay shield by sparkfun". You might also prefer some electronic 'driver' vs a relay for those valves. Again more detail is needed.

Stackable headers can be added, a bigger concern would be which shield uses what pins. It’s not unusual to find 2 shields that want to use the same pins. You may find using a Breakout Board (BoB) is preferable to another stacked shield.

I’m sorry it was the Sain Smart 8 relay board, I was mixed up on the brands.

The reason for thinking about using the relay board instead of drivers is the valves I have right now on hand are pretty heavy power consumers not sure on the exact spec but I would be worried about overheating issues on holding them open. Timing isn’t super critical so a small delay form relay-relay shouldn’t be an issue

I’m thinking along the same lines now looking at some of the components and easy of wiring/trouble shooting to just use breakout boards.

I will most likely design and print a modular enclosure that will house the different boards and connect together to keep everything “protected” and maybe make use of a small fan to keep things cool.

On this note, with the stepper driver below should I consider adding shielding to the case section housing that driver?

So far I have the following on my parts list:

L298N Dual H-Bridge Motor Driver Module such as:

http://www.amazon.com/gp/product/B00CAG … UTF8&psc=1

Arduino Mega 2560 R3 such as:

http://www.amazon.com/gp/product/B006H0 … UTF8&psc=1

Kootek 8 Channel DC 5V Relay Module:

http://www.amazon.com/gp/product/B00C8O … UTF8&psc=1

Stepper Motor - 58 oz.in (400 steps/rev)

http://www.amazon.com/gp/product/B007R9 … UTF8&psc=1

Phantom YoYo 40P dupont cable 200mm male to female

http://www.amazon.com/gp/product/B00A6S … os_product

12v 10A power supply:

http://www.amazon.com/gp/product/B007C0 … os_product

9v 650mA power supply:

http://www.amazon.com/gp/product/B00BWA … os_product

I already have a k-type chromel-alumel that should be in the range of 8-15 mV in the usable range I need, any recommendation on a amplifier to jump this up to usable values?

4

First thing I note is that your H bridge motor driver is meant for a DC motor, not a stepper. One stepper driver would be;

https://www.sparkfun.com/products/11876

What are your motor reqs ? Do you need it to be reversible ? Variable speed ? Torque monster or ??

Are the valves AC (?60 Hz?) or DC ? Any clue on their current draw ? Even relays need to be properly sized.

https://www.sparkfun.com/products/306

https://www.sparkfun.com/products/307

5

Mee_n_Mac:
First thing I note is that your H bridge motor driver is meant for a DC motor, not a stepper. One stepper driver would be;

https://www.sparkfun.com/products/11876

What are your motor reqs ? Do you need it to be reversible ? Variable speed ? Torque monster or ??

Are the valves AC (?60 Hz?) or DC ? Any clue on their current draw ? Even relays need to be properly sized.

https://www.sparkfun.com/products/306

https://www.sparkfun.com/products/307

Hey thanks for the input! I will have to look into the motor driver confusion.

Motor requirements would mostly be torque as a higher priority. about every 20 seconds the motor will complete ~1-2 complete revolutions turning a small screw that “pushes” or feeds small plastic pellets from a hopper to a slide where gravity guides them into the hot chamber. one direction only, no need to reverse

The desired characteristic is to be able to precisely “tune” the amount it turns per cycle to be able to deposit the correct amount of plastic.

I’m starting to think it might be worth wild to just pick up a used festo valve manifold that operates on 24v dc. They pull about 100-150mA max/valve