Electrical Engineering V3 - Developers

I'm thinking about building a fully discrete bucket brigade device delay line, but I'm trying to figure out what determines the clock frequency range? Like most analog BBDs clock around 20-200KHz, is there a reason for this limitation?

[QUOTE=The Salmon;52289712]I'm thinking about building a fully discrete bucket brigade device delay line, but I'm trying to figure out what determines the clock frequency range? Like most analog BBDs clock around 20-200KHz, is there a reason for this limitation?[/QUOTE] Atleast, digitally speaking, you need to consider the threshold voltages of both the High & Low logic levels, and then the source/sink current of the previous output stage. Most BBDs had such low frequencies probably because of the technology node they were produced at at the time (i.e the [URL="http://www.geofex.com/sad1024.htm"]sad-1024[/URL] made in 1980) using nMOS gates at the time of ~3um gate width which has a pretty significant inherent gate delay to start with.

I've been trying to implement a D flipflop with as few 555 timers as possible for a project. I just managed to get it down to 6 :D [IMG]http://i.imgur.com/ri3QnYK.png[/IMG] how my circuit works now: [IMG]http://i.imgur.com/B31x52C.png[/IMG] [editline]blah[/editline] Top and right latches are each one 555. You can wire the 555 up so that only the S input is inverted, compared to S and R both being inverted on a normal NAND latch. In the bottom latch, the 2-input gate is a single 555, and the 3-input gate needs 3.

I'm hungry for some electronics :v: [video=youtube;8rRRvgjLjZU]http://www.youtube.com/watch?v=8rRRvgjLjZU[/video] Brb gonna make a 74 series computer running at 1GHz.

[QUOTE=LoneWolf_Recon;52296082]I'm hungry for some electronics :v: [video=youtube;8rRRvgjLjZU]http://www.youtube.com/watch?v=8rRRvgjLjZU[/video] Brb gonna make a 74 series computer running at 1GHz.[/QUOTE] Wouldn't trace impedance ultimately make that next to impossible? Also if that one inverter chip got up to 60C then holy shit will you have a temperature management nightmare on your hands. :v: In fact, if you DO build it, might I interest you in a suitable heat-sink? [t]http://i.imgur.com/erqO0Tu.jpg[/t]

Wow that short range Bluetooth jammer got me interested Would be a great joke if one of your friends plays some song you dislike on a bluetooth speaker

I am trying to design a power control circuit for Raspberry Pi, which connects power when a button is pressed, sends a signal to the Pi's GPIO to shut down if it is pressed again, then disconnects power once the Pi has shut down. Here is what I have so far: [img]http://i.imgur.com/U9eFIkp.png[/img] The problem here is though, since BOOTED_IN will probably not be HIGH until the Pi fully boots, it will probably turn itself back off immediately. What can I do to counter that?

[QUOTE=daigennki;52306178]I am trying to design a power control circuit for Raspberry Pi, which connects power when a button is pressed, sends a signal to the Pi's GPIO to shut down if it is pressed again, then disconnects power once the Pi has shut down. Here is what I have so far: [img]http://i.imgur.com/U9eFIkp.png[/img] The problem here is though, since BOOTED_IN will probably not be HIGH until the Pi fully boots, it will probably turn itself back off immediately. What can I do to counter that?[/QUOTE] Delay circuitry? Probably a ne555 wired as a slow Monostable timer

[QUOTE=daigennki;52306178]I am trying to design a power control circuit for Raspberry Pi, which connects power when a button is pressed, sends a signal to the Pi's GPIO to shut down if it is pressed again, then disconnects power once the Pi has shut down. Here is what I have so far: [img]http://i.imgur.com/U9eFIkp.png[/img] The problem here is though, since BOOTED_IN will probably not be HIGH until the Pi fully boots, it will probably turn itself back off immediately. What can I do to counter that?[/QUOTE] Simpler and less power intensive solution than all those gates. [video=youtube;Foc9R0dC2iI]http://www.youtube.com/watch?v=Foc9R0dC2iI[/video]

[QUOTE=Van-man;52307158]Delay circuitry? Probably a ne555 wired as a slow Monostable timer[/QUOTE] Not sure how I would use a timer or how a delay would help here, what do you have in mind? [QUOTE=LoneWolf_Recon;52307194]Simpler and less power intensive solution than all those gates. [video=youtube;Foc9R0dC2iI]http://www.youtube.com/watch?v=Foc9R0dC2iI[/video][/QUOTE] Looks good, but I do not want to disconnect the power right away, I want to allow the Pi to shut down safely. How might I add to the circuit to allow the Pi to shut down safely before disconnecting power?

[QUOTE=daigennki;52308206]Not sure how I would use a timer or how a delay would help here, what do you have in mind? Looks good, but I do not want to disconnect the power right away, I want to allow the Pi to shut down safely. How might I add to the circuit to allow the Pi to shut down safely before disconnecting power?[/QUOTE] [IMG]http://i.imgur.com/t5yZsPR.png[/IMG] I just added two N-channel MOSFETs, two pull-downs & two series resistors that would be connected to two GPIO pins on the RPi. The Hold Pin is equivalent to your BOOTED_IN pin, which keeps the power supply on to power the Pi (Thus this must be held High until safe to power off). When everything is safe to power off, have the Pi's GPIO send a High signal to the Safe To Shutdown pin. Edit: In retrospect you might need an inverter on the Safe To Shutdown pin?

[QUOTE=LoneWolf_Recon;52308558][IMG]http://i.imgur.com/t5yZsPR.png[/IMG] I just added two N-channel MOSFETs, two pull-downs & two series resistors that would be connected to two GPIO pins on the RPi. The Hold Pin is equivalent to your BOOTED_IN pin, which keeps the power supply on to power the Pi (Thus this must be held High until safe to power off). When everything is safe to power off, have the Pi's GPIO send a High signal to the Safe To Shutdown pin. Edit: In retrospect you might need an inverter on the Safe To Shutdown pin?[/QUOTE] Ooh, this looks nice. Also, apparently the UART TX pin on the Pi is on as long as it is not shut down in any way, so I will connect it to the Safe to Shutdown pin and add an inverter to that. It means I will not be able to use UART, but I have no intentions of using it so that should not be a problem. Thank you, I will try this out! [editline]4th June 2017[/editline] Okay, should it look something like this? [img]http://i.imgur.com/Fcfzui7.png[/img]

[IMG]http://i11.photobucket.com/albums/a166/ballsandy/New%20Bucket/CGS_7603.jpg[/IMG] I need a wiring diagram. :suicide:

ewww

Well, at any rate, if you need advice on the refrigeration side of things I can provide. :v:

I'll need it. I pressure washed the evaporator coil and compressor frame and got what looks like an oil sheen so the loop has a hole somewhere.

[QUOTE=pentium;52319376]I'll need it. I pressure washed the evaporator coil and compressor frame and got what looks like an oil sheen so the loop has a hole somewhere.[/QUOTE] If it has a hole, I'd be worried about water seeping in as well. As long as it's not hydroscopic oil you should be able to pull any water out with a good, deep vacuum, some warmth from a lamp, and some time. But naturally, find the leak first. Though it's also possible that the oil sheen is from multiple service procedures where oil may have sprayed out when they were disconnecting the hoses, 25PSI of dry nitrogen and some soapy water will help find any holes.

Does anyone have any experience programming the ESP8266-01 Wifi chip with the Arduino IDE? I'm losing my fucking mind trying to upload things and getting an espcomm_sync error despite the thing responding to AT commands. Other code works fine but as soon as I need to compile with the ESP8266 libraries I get that error. The reset, GPIO2, and CH_PD are set high, the GPIO0 is low for programming mode, and I'm resetting it between mode , and I can transmit data perfectly between the two. I am trying to set up a Web device to transfer images I'm taking through an arduino mega, and it requires I set up the right responses to particular client requests.

[QUOTE=solid_jake;52320665]Does anyone have any experience programming the ESP8266-01 Wifi chip with the Arduino IDE? I'm losing my fucking mind trying to upload things and getting an espcomm_sync error despite the thing responding to AT commands. Other code works fine but as soon as I need to compile with the ESP8266 libraries I get that error. The reset, GPIO2, and CH_PD are set high, the GPIO0 is low for programming mode, and I'm resetting it between mode , and I can transmit data perfectly between the two. I am trying to set up a Web device to transfer images I'm taking through an arduino mega, and it requires I set up the right responses to particular client requests.[/QUOTE] EEVBlog released a video not too long ago that explains how to do just that. [media]https://www.youtube.com/watch?v=Q6NBnPfPhWE&t=304s[/media]

[QUOTE=Zero-Point;52319094]Well, at any rate, if you need advice on the refrigeration side of things I can provide. :v:[/QUOTE] Sorry, looks like my refrigeration problems are not the kind of thing you can help with remotely. [IMG]http://i11.photobucket.com/albums/a166/ballsandy/New%20Bucket/CGS_7615.jpg[/IMG]

Yeesh. [I]Sometimes[/I] a skilled person can use brazing rod to fill a hole without filling in the tube, but a hole that size is a definite "no". Lucky for you there should be replacement coils available. Just gotta figure out the "tonnage" (capacity) of the system and get something close to that.

I'll just replace the compressor and condenser as a set. The evaporator is specific to the machine but has threaded ends so you can replace the entire refrigeration unit. [img]http://i11.photobucket.com/albums/a166/ballsandy/New%20Bucket/CGS_7616.jpg[/img]

That thing sure looks ready to retire!

[QUOTE=pentium;52328616]I'll just replace the compressor and condenser as a set. The evaporator is specific to the machine but has threaded ends so you can replace the entire refrigeration unit. [img]http://i11.photobucket.com/albums/a166/ballsandy/New%20Bucket/CGS_7616.jpg[/img][/QUOTE] True, I forgot you can also buy the condensing units as a complete unit. I do wonder what rubbed that hole in the coil though.

It wasn't rubbed. It is corrosion. Massive amounts of corrosion. Gee, you Vancouver EE's why the fugg are you not visiting me at the Vancouver Maker Fair? I'm just standing here at table #001 all day right next to the entrance. So lonely. Please visit me. ;_;

[QUOTE=pentium;52340840]It wasn't rubbed. It is corrosion. Massive amounts of corrosion. Gee, you Vancouver EE's why the fugg are you not visiting me at the Vancouver Maker Fair? I'm just standing here at table #001 all day right next to the entrance. So lonely. Please visit me. ;_;[/QUOTE] Corroded? Are those tubes steel? Or copper/aluminum?

[QUOTE=Zero-Point;52345960]Corroded? Are those tubes steel? Or copper/aluminum?[/QUOTE] Likely steel with copper links connecting the compressor and condenser.

Just seems weird that the condensing coil would be made of steel, particularly in a vending machine. Poor heat transfer in particular, and for a condenser that small you'd want decent heat conductivity.

So it's been decided by management that I'll be in charge of monitoring two 69kVA lines and three 20MVA transformers for 12 hours on Sunday because our generators died and we need to make sure that our emergency wiring job doesn't overload. Apparently the mill was never designed to be able to run with grid power alone, and if we tried to pull full load without this jumper setup we'd melt our incoming lines. "You know I've never done anything higher than 120V before right?" "That's fine it's basically the same thing" So I've got to stay awake from 6 to 6 and make sure nothing blows up. Sounds like a perfectly normal assignment for an intern who's only been working at the plant for a month. [sp]I'm actually pretty hyped because high voltage stuff is fucking cool[/sp]

So you get to spend 12 hours walking around with a FLIR and watching the lines sag?