EcoRenovator - View Single Post - Hacking a Kill-a-Watt for very low power measurements

NiHaoMike · 08-23-14, 04:54 PM

I actually had to design a digital power meter as part of a class project. Even on something as basic as a dsPIC (much slower than even a low end ARM), it's not very difficult to make the code work in real time with a 250kHz sample rate. The antialiasing filters are around 20kHz, giving it plenty of bandwidth for mains power measurements.

I do agree, however, that equivalent time sampling holds lots of traps for unsuspecting beginners. Fortunately, no knowledgeable engineer (nowadays) would use equivalent time sampling at such low frequencies.

08-23-14, 04:54 PM	#42
NiHaoMike Supreme EcoRenovator Join Date: Oct 2008 Location: Austin, TX Posts: 1,154 Thanks: 14 Thanked 257 Times in 241 Posts	I actually had to design a digital power meter as part of a class project. Even on something as basic as a dsPIC (much slower than even a low end ARM), it's not very difficult to make the code work in real time with a 250kHz sample rate. The antialiasing filters are around 20kHz, giving it plenty of bandwidth for mains power measurements. I do agree, however, that equivalent time sampling holds lots of traps for unsuspecting beginners. Fortunately, no knowledgeable engineer (nowadays) would use equivalent time sampling at such low frequencies. __________________ To my surprise, shortly after Naomi Wu gave me a bit of fame for making good use of solar power, Allie Moore got really jealous of her...