Search found 70 matches

by pngaudioguy
Wed May 13, 2015 7:21 am
Forum: Wiring, Electrical, Relays and Sensors
Topic: Element Switching Relays
Replies: 10
Views: 8847

Re: Element Switching Relays

Hm - that's pretty interesting! So the NAND gate would trigger the relay selecting the element output? Would you still have to have a low pass filter on the PWM signal to keep the gate triggered? Edit: The datasheet for the TI 7400 indicates 7-15 nano seconds as the trigger time, and .7-2V as trigge...
by pngaudioguy
Sun May 10, 2015 8:09 am
Forum: Wiring, Electrical, Relays and Sensors
Topic: Element Switching Relays
Replies: 10
Views: 8847

Re: Element Switching Relays

Thanks for the clarification. I've done a bunch of research today, and I'm thinking that one could also use a simple series resistor and parallel capacitor to form a low pass filter converting the PWM output to analog voltage. You could then add a transistor to increase the drive voltage to stay abo...
by pngaudioguy
Sat May 09, 2015 1:41 pm
Forum: Wiring, Electrical, Relays and Sensors
Topic: Element Switching Relays
Replies: 10
Views: 8847

Re: Element Switching Relays

I know I'm reviving a ridiculously old thread here, but numerous Google and forum searches haven't quite answered my question. In the described scenario, you're using the PWM output from the two element outputs to drive the coil circuit of a relay to open a circuit. Do you need to use an opto-isolat...
by pngaudioguy
Sun Apr 26, 2015 12:14 pm
Forum: Troubleshooting and Support
Topic: Normal temp probe fluctuations?
Replies: 13
Views: 9953

Re: Normal temp probe fluctuations?

These are the type of issues that make me want to have a dedicated, standalone PID backup, JonW...

The system doesn't have to completely die to be completely useless. +/- 6 degree fluctuations are 100% unacceptable in my book.
by pngaudioguy
Thu Apr 09, 2015 7:03 pm
Forum: General Discussion
Topic: Pre-planning stages of BCS based homebrewery
Replies: 70
Views: 46668

Re: Pre-planning stages of BCS based homebrewery

Coincidentally, our offer just got accepted on a house today. It has 875 square feet of unfinished basement that's 7.5 feet tall. Brew space confirmed.
by pngaudioguy
Thu Apr 09, 2015 1:27 pm
Forum: General Discussion
Topic: Pre-planning stages of BCS based homebrewery
Replies: 70
Views: 46668

Re: Pre-planning stages of BCS based homebrewery

JonW, You're right. I'm over-complicating it. I've been told I have a tendency to do that. I work in IT and don't trust computers, even embedded ones. Things fail - maybe not today, maybe not tomorrow, but someday. When they do, $100 is really cheap insurance per my book. :) If I never ever use thos...
by pngaudioguy
Sat Apr 04, 2015 12:55 pm
Forum: General Discussion
Topic: Pre-planning stages of BCS based homebrewery
Replies: 70
Views: 46668

Re: Pre-planning stages of BCS based homebrewery

Ok, build is getting really close now! Less than 3 months until I start assembly. Aside from "exact" control placements, I think this is going to be the panel. As I was talking it over with my wife she says, "Why not just do both?" "Because it'll be more expensive," I s...
by pngaudioguy
Fri Mar 27, 2015 9:51 am
Forum: General Discussion
Topic: Pre-planning stages of BCS based homebrewery
Replies: 70
Views: 46668

Re: Pre-planning stages of BCS based homebrewery

Hm. Reworked my panel idea again. So, here's concept "I", I think I'm up to... This one goes with everything controlled from a touchscreen embedded in the panel (WinBook TW700 @$79.99 from Amazon.) There's still a key power, emergency stop, alarm buzzer and physical reset button for the al...
by pngaudioguy
Wed Mar 25, 2015 11:59 pm
Forum: Troubleshooting and Support
Topic: Normal temp probe fluctuations?
Replies: 13
Views: 9953

Re: Normal temp probe fluctuations?

Is your shielded DB25 grounded at both ends? If so, try floating one end (I would float the end further from the BCS.) That would be what we call a "ground loop" in pro audio land. Causes tons of noise in audio circuits, and I imagine in these low voltage control circuits as well. The two ...
by pngaudioguy
Wed Mar 25, 2015 11:02 am
Forum: General Discussion
Topic: Pre-planning stages of BCS based homebrewery
Replies: 70
Views: 46668

Re: Pre-planning stages of BCS based homebrewery

Hi Guys, First post here, but have been lurking for a while. <snip> Great first post, and welcome! What are your thoughts about going to a 2 kettle system rather than three? I would eliminate the HLT and just use a well-powered RIMS element for heating MLT water and on-demand sparge water. It would...