I would like to build a device that compares two temperatures (one being the room temp and the other being the air coming from the HVAC vent). I would like the device/circuit to produce a powered output one way or the other. If the temp is the same or colder from the vent, it can be +, or off, or anything else. If it senses that the vent is producing high temp, it would be a -, or on, etc. While I’d be ok with just the two states, if the cost, effort and labor is minimal, a three state (hotter, colder, relatively close to same temp) could also be used.
If this is something to be built what would you charge to build it. I currently do not have tools or space to build.
This is my first post and I can see myself returning often.
Thank you both for replying. My imagination my have overpowered my budget. I looked at a number of commercial ones or stuff from small manufacturers. Even the smallest seemed to be $30 a piece and did more than I needed. I simply need to have a different output if one measurement is hotter than the other measurement. As mentioned, it can be off until it’s hotter, then it send a signal. This is for a simple 12V (or 5V) project.
It can be built for less than $30 in parts, but you’d definitely have to DIY. I have a design somewhere that does this. It was for an attic vent fan that turned on if the attic was x degrees hotter than the outside air. Parts probably cost around $10. You could build it on a kitchen table.
But as you (codlink) say, having someone do it for you will certainly cost more than $30 assuming you want them to do a good job.
