Reddit mentions: The best pressure probes & sensors

I actually didn't tally up the cost as that wasn't really of a concern to me, but I'll try my best to provide links to the things I bought for this. Feel free to add it up for me!

• Lighting
  
  • T-5 Grow light (came with 6500K bulbs)
    
  • 2700K bulbs
    
  • Grow light hangers
    
• Grow medium
  
  • Net Cups
    
  • Black Buckets
    
  • Black lids
    
• Nutrients
  
  • General Hydroponics Flora Series
    
  • General Hydroponics pH control kit
    
  • pH/EC/Temp Meters
    
• Grow tent
  
• Air ventilation
  
  • The only thing I ended up using from this kit was the cheapest part, the ventilation duct...
    
  • The fan from this kit is way too powerful for my setup because my humidifier couldn't keep up
    
  • I didn't use the carbon filter because I'm not growing weed.
    
• Water Distiller
  
• Humidifier
  
  • The cheaper the humidifier, the better. I first bought (and destroyed) one that had some sort of digital switch, so it would always be in the off state when you first supply power to it, meaning you can't turn it on/off with just a relay.
    
• Plumbing
  
  • Aquatec 8852 booster pump
    
  • 2 Gallon accumulator tank
    
  • Pressure relief valve
    
  • Tubing
    
  • Inline Pre-filter (Sorry they must have taken the product down...)
    
  • Misting nozzle T's
    
  • Tube ball valves
    
  • Analog pressure gauge
    
  • Misting Nozzles
    
    • Note that these nozzles are meant for WAY higher pressure systems (~1000psi) and I actually had to take out the spring for them to operate correctly, but they never clogged up, are easy to clean, and worked perfectly for me!
      
• Electronics
  
  • Raspberry Pi 3 kit
    
  • Humidity sensor
    
  • Pressure sensor
    
  • Water solenoid valve
    
  • 5V 4-channel relay module
    
  • Analog-to-digital converter
    
  • 24V to 12V converter
    
  • 24V Power supply
    
  • Resistor kit
    
  • Semiconductor kit
    
  • Circuit boards
    
  • Standoffs
    
• Wiring
  
  • 22 gauge stranded wire
    
  • 22 gauge solid wire
    
  • Power supply cord
    
• Connectors
  
  • Electronic Connectors
    
    • JST-XHP Connectors
      
    • JST-SM Connectors
      
    • Dupont Connectors
      
  • Plumbing Connectors
    
    • Bulkhead connectors
      
    • Quick-connect kit
      
    • NPT to quick-connect connector
      
      I also bought various tools, like crimpers, Dremel kit, drill, etc, but I don't consider those to be project-specific as I'll have them for the foreseeable future. Let me know if there's anything you see that you think I missed!
      

Skip both of those sensors and get a BME280 sensor, instead. $7 on Amazon (or less if you buy more than one), works on I2C. And you get temp, humidity and barometric pressure in one easy to use sensor.

If you use it with an ESP32, be sure to keep the sensor away from the ESP itself. There have been numerous posts recently about the heat from the ESP affecting the readings of these temp sensors, especially if they're both in a small enclosure.

You'll need a relay, but be sure to get one that'll handle the current of a space heater. How many amps does that heater pull? Many of the arduino relay modules out there have 10A ratings. A 1500W heater is going to pull 12.5A, so I'd get something with more current handling capability. This optocoupler isolated, 30A relay would work, though. You can get 3 of them for $20 and have spares on hand if one kicks the bucket.

You could do simple control where the relay energizes at the low temp and de-energizes at the high temp, or you could look into using PID control. I'd start with the simple set method, then learn how to implement PID control once you have it working and want better control over temperature and energy usage.

I hadn't thought about load cells before for this, maybe that will be a simpler approach. I'll try to get a picture of the trays tonight for better context.

Currently each drawer has one long tray that is segmented into the individual trays (usually for keeping sticks of each value). I could potentially build out an inner tray into each of these with a load cell (or a force resistor? would that work? something like: https://www.amazon.com/Sensitive-Resistor-Pressure-Diameter-Resistance-Type/dp/B07MP4RL9Q/ref=pd_cp_147_4?pd_rd_w=rApgs&pf_rd_p=ef4dc990-a9ca-4945-ae0b-f8d549198ed6&pf_rd_r=YJYEX2GZSM394H0DA4W8&pd_rd_r=da7d2b5b-8e6a-4c21-a6a4-186172b7f89a&pd_rd_wg=FPPGa&pd_rd_i=B07MP4RL9Q&psc=1&refRID=YJYEX2GZSM394H0DA4W8) that would sit between the inner and outer trays and determine how many sticks are in that inner tray.

I would be satisfied with just counting "sticks in tray" initially and just specifying individual trays as a particular point value rather than trying to differentiate between sticks.

Iunlock guide has great information for apply LM the heat sink your wanting is a sunon. http://forum.notebookreview.com/threads/alienware-17r4-15r3-disassembly-repaste-guide-results.797373/
Pressure paper is expensive but I do see it on Amazon they have samples now for like $7 that's the perfect size for 3 or test.https://www.amazon.com/Fujifilm-Prescale-Sample-Pressure-Indicating/dp/B079C5FX6T/ref=mp_s_a_1_3?ie=UTF8&qid=1542136584&sr=8-3&pi=AC_SX236_SY340_FMwebp_QL65&keywords=pressure+paper&dpPl=1&dpID=41Glll94FnL&ref=plSrch Basically it let's you test that even pressure is being made with the die so you can figure out which pads you may want to decrease in height. To be honest with you I didn't use it. it just took me a couple of tear downs adding a little extra LM and then bending the CPU arm on the heatsink to get the core differential down to 4c max.

I think there is a possibility of using your other arm to access modifier keys to double or triple the number of buttons you can use.

Maybe something like this

Held in place by a velcro attached to an arduino that can act as a single key "keyboard".

You could probably even make it do multiple keys based on how hard you're pressing.

Have you looked at something like this?

https://smile.amazon.com/gp/product/B01MCVOZJO/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I'm experimenting with one to detect the differential pressure on my septic air pump to have an alert if it stops

Pressure sensor
https://www.amazon.com/dp/B07MHTWR1C/ref=cm_sw_r_cp_apa_i_7dTVDbYG37Y0N


Insteon sensor (only works with Insteon systems)
https://www.amazon.com/dp/B00O0LH9SQ/ref=cm_sw_r_cp_apa_i_bfTVDb50NSJS8


Zwave sensor

Looks like based on the photos in the description, this one may have screw terminals (the green square with screw heads on the photo of internals)
I don't know for sure so you'll need to do your research.

https://www.amazon.com/dp/B07PDDX3K6/ref=cm_sw_r_cp_apa_i_ZjTVDbJC5H32A

There's not a lot to show, but I threw together a couple of quick wiring diagrams:
https://imgur.com/gallery/aKN9joL

Otherwise, here are the links I posted above:
ADC board: WaveShare AD/DA board based on the ADS1256
Diff. Pressure sensor: DIYmore Breakout Board for the MPXV7002 sensor

And here is a PDF of the actual schematic of the WaveShare board as posted from the WaveShare AD/DA page posted prior:
https://www.waveshare.com/w/upload/2/29/High-Precision-AD-DA-board.pdf