$2.65 IR Proximity Relay Kit

erco

Another Ebay deal where the sum of the parts seems like a pretty good value. Must trigger at an adjustable DC level of reflected IR since the 4093 IC is just NAND gates, so this isn't a high tech sensor. A 38 kHz sensor & circuit would be more reliable, but who am I to look a gift horse in the mouth.

If nothing else, it looks like a nice PCB, so soldering the non-SMT parts may be fun for us old Heathkit lovers, or an intro to electronics for someone's budding young scientist. Win the whole science fair when your kid turns on a lamp or something else when you or Rover is detected.

http://www.ebay.com/itm/222115701652

hatallica

Wow. A 4093 NAND gate timer seems like such a Rube Goldberg machine to me. Are they dirt cheap or something? It requires 2x the peripheral components and PCB real estate as even a simple 555 circuit.

That said ... I would favorably judge a science fair project that used this to trigger a hands-free Goop/Gojo dispenser.

erco

hatallica wrote: »

That said ... I would favorably judge a science fair project that used this to trigger a hands-free Goop/Gojo dispenser.

Not sure that Gojo flows very well, but there are some cheap electric fluid pumps which might work with this sensor for thinner liquid soaps.

http://www.ebay.com/itm/DC-12V-Motor-Durable-Electric-Tea-Pot-Tea-Tray-Mini-Gear-Water-Pump-5-45-/391497048658