So I upgraded my power supply:
[IMG]http://i.imgur.com/RMECD4T.jpg?1[/IMG]
I was bothered that the analog dial and single turn pots only gave me a reliable 100mV resolution and required manual ranging of the analog readout, so for a little under $20 I bought 5-digit volt and amp meters and two 10 turn pots.
The hole in the front panel for the analog dial was too big to simply widen to a rectangle and stick the digital meters in, so I had to make a cover plate to hold the meters. I was gonna paint it black, which would have looked much better, but the nozzle on my can of black paint broke off.
It looks a bit ghetto but I'm fine with it.
Looks a hell of a lot better than some of the other digital display conversions I've seen.
Edited: Back to my chip programmer, I decided that it would be easier to replace a very expensive and hard to source rotary knob with five more toggle switches and an edit to the manual.
[IMG]http://i11.photobucket.com/albums/a166/ballsandy/Computer%20related/Specials.png[/IMG]
So had to do a repair possibly more obnoxious than the power jack.
Some guy in our local gaming community wanted me to do the same repair for his, but he found a replacement part that fixed that. Problem is he somehow fucked up his CMOS battery while doing it, ripping the trace off the board.
So I had to use an X-acto knife to scrape the green shit off the trace that was left (it was UNDER the battery), tin it, and then try to blob enough solder on it so when I heated the other leg of the battery holder it would catch.
Thankfully, he says it works fine now.
Sorting out parts for my 3 radios is a real pain in the ass, particularly as these old radios use quite a few odd values like 137pF, 324pF, 40uF, etc, also I've yet to find a distributor that sells single parts and low cost delivery, I'm considering using Mouser but the £12 delivery is really eating into my budget.
Sigh.
[QUOTE=Chryseus;41726050]Sorting out parts for my 3 radios is a real pain in the ass, particularly as these old radios use quite a few odd values like 137pF, 324pF, 40uF, etc, also I've yet to find a distributor that sells single parts and low cost delivery, I'm considering using Mouser but the £12 delivery is really eating into my budget.
Sigh.[/QUOTE]
Parallel a few caps tight tolerance caps together? Tuning caps are another option.
[QUOTE=LoneWolf_Recon;41730244]Parallel a few caps tight tolerance caps together? Tuning caps are another option.[/QUOTE]
That usually works yes, in most cases it isn't critical and you can pick the nearest standard value but some need to be very close, thankfully most of them are in good condition so I'm going to hold off on replacing them unless a problem does appear, tuning caps of a reasonable size are only good for around 50pF.
Getting them to the point where I can power up is my goal at the moment, the electrolytics and paper wax caps are pretty much all bad and some of the resistors have drifted quite far off.
At least all the tubes that haven't smashed test good.
[QUOTE=Chryseus;41732284]That usually works yes, in most cases it isn't critical and you can pick the nearest standard value but some need to be very close, thankfully most of them are in good condition so I'm going to hold off on replacing them unless a problem does appear, tuning caps of a reasonable size are only good for around 50pF.
Getting them to the point where I can power up is my goal at the moment, the electrolytics and paper wax caps are pretty much all bad and some of the resistors have drifted quite far off.
At least all the tubes that haven't smashed test good.[/QUOTE]
Considering its tubes, I'd imagine finding highly accurate and rather high voltage caps a problem.
[QUOTE=LoneWolf_Recon;41733468]Considering its tubes, I'd imagine finding highly accurate and rather high voltage caps a problem.[/QUOTE]
Most of the time caps that need high accuracy are in the RF stages where voltage isn't that big of an issue, the main problem I have is sourcing higher value high voltage caps, most smaller stores that offer cheap delivery don't sell them which is rather annoying.
Any recommendations for where I can sell a [url=http://www.ebay.com/gds/HP-16500-Series-Mainframe-Logic-Analyzer-Oscilliscope/10000000009183958/g.html]HP 16500C digital logic analyzer mainframe[/url]? I've listed it on eBay before to no avail. I feel like it's too specialized for some random person on eBay to want to buy it.
I had a friend buy a 16500 for $350 back in January. Awesome machines but most people veer away if:
-you're a twat and separate the pods and boards from the unit
-try and sell it for a fortune and have absolutely NO information confirming it's fully functional.
Finally got my class AB power driver working after many problems.
Keep in mind this is only the power stage, if you intend to build it you will need a pre-amplifier.
[img]http://u.cubeupload.com/Chryseus/Yvv147.png[/img]
Hey guys, stopped off at hamfest today as i do every year, look @ this tube:
the numbers 3037 are written on it and 'Made In England' on the heatsink, pics:
[URL=http://imgur.com/vZ8BBNc][IMG]http://i.imgur.com/vZ8BBNcs.jpg[/IMG][/URL]
[URL=http://imgur.com/zIMOG7j][IMG]http://i.imgur.com/zIMOG7js.jpg[/IMG][/URL]
Anyone know much about it
Best part of today is:
I Also got contact with a guy who has a friend that fixes electron microscopes and such, i MAY or may not
be able to get hold of 12x 20Kv @ 200uf capacitors (450KJ nearly 1/2 MJ!) but that wont be for a while i think...
450KJ...0.45MJ.... what the hell will i do with that :L
[QUOTE=nuttyboffin;41797923]
450KJ...0.45MJ.... what the hell will i do with that :L[/QUOTE]
May I suggest killing people?
mmm, mabye a rail gun im thinking.... :3
[QUOTE=nuttyboffin;41797923]Hey guys, stopped off at hamfest today as i do every year, look @ this tube:
the numbers 3037 are written on it and 'Made In England' on the heatsink, pics:
[URL=http://imgur.com/vZ8BBNc][IMG]http://i.imgur.com/vZ8BBNcs.jpg[/IMG][/URL]
[URL=http://imgur.com/zIMOG7j][IMG]http://i.imgur.com/zIMOG7js.jpg[/IMG][/URL]
Anyone know much about it [/QUOTE]
It's probably a power triode or tetrode, maybe rated for a few kW.
[b]YES![/b]
I found a page that very easily calculates lengths for antennas.
[url]http://www.qsl.net/kb5wck/antenna.html[/url]
So because I want a decent CB base station antenna a 5/8 wave vertical standing antenna explicitly for CB will need to be 21.5 feet tall. I'll buy some PVC pipe and 12 gauge copper wire, run the wire down the pipe and pull it tight at each end and with some impendence matching I'll be set.
So a while back, the ROM chip in that breadboard computer I built had a fight with an Arduino and lost... (there was a mistake in the programmer code that left the OE pin low, so there was contention). I couldn't find the same part anywhere so I ended up putting in a big flash chip, but the timing was all wonky and it wouldn't run faster than ~2.5MHz (and even that was wobbly).
I went on Farnell the other day to get some parts, and just about spat my drink out when I saw that the chip I was after was now in stock at Farnell!
Computer's back up to 8MHz now:
[t]http://i.imgur.com/r7dpco5.jpg[/t]
It's running the Fibonacci sample there, which is actually fairly involved (loads of branches and function calls, some arithmetic) so I'm pretty confident in the stability - it's computing the 14th fibonacci number as 121 in the photo (mod 256, it's actually 377), red switches are input and LEDs are output.
I've now got the bits to start building up the mass storage board, and after a bit more work on the compiler I can start building up a simple OS to load and run programs off the half megabyte flash chip. Outlook's good! :)
[editline]blah[/editline]
Don't mind the wires on the right, I took the screen off while I was wiring the new chip in.
What's the Arduino used for? Programming it?
[QUOTE=Agent766;41835885]What's the Arduino used for? Programming it?[/QUOTE]
Yeah, the big black chip near the centre is an EEPROM that holds the boot code, the arduino hooks up to the data bus and the LE pins of the address latches, so it can control the data and address buses, and then there's a sketch with a serial console that lets me manipulate the buses, test things, and program a data file stored on the arduino's flash into the EEPROM, all controlled from a PC.
Modified the programmer sketch today to use the EEPROM's page write mode - this lets it program 64 bytes in a single write cycle, which gives a ~50x speedup!
The screen driver code is running again and the whole thing is as fast and more stable than ever :)
[editline]blah[/editline]
I've added a 6th board, the flash chip and all the IO ports to control it are on there but there's a lot of wiring and programming to be done before it'll work.
Wouldn't it be neat if computers had GPIO?
[url]http://www.lightharmonic.com/lightspeed.html[/url]
my desk has dent shaped like a forehead now
Wired the storage board up today!
[t]http://i.imgur.com/mPJQ0hj.jpg[/t]
Time for some more programming :v:
[editline]blah[/editline]
[quote=]In fact, LightSpeed's astounding [B]10 Gigabits per second bandwidth is twice as fast as USB 3.0[/B]![/quote]
:(
So, the door to my room has this:
[t]http://i.imgur.com/16hHCcz.jpg[/t]
But I thought that looks a bit sad, so I decided to order a PCB to put in there! This is the design:
[t]http://i.imgur.com/fIy66HI.png[/t]
It will have black soldermask and an ENIG finish, for maximum Bling
[QUOTE=DrDevil;41862073][url]http://www.lightharmonic.com/lightspeed.html[/url]
my desk has dent shaped like a forehead now[/QUOTE]
*sniff* You guys smell that?
*sniff sniff* Smells like... Snake oil?
So, I'm new to this whole electrical engineering thing and I haven't started yet really but I have a project in mind. I'm using a Raspberry Pi as my base to be a main hub controller thing.
My main question here is this though. I'm looking to power my Raspberry Pi and then some motors, probably in parallel. I need to take the output of my battery which is 7.4V (2x3.7V) through a voltage regulator (5V) and then I need to turn the JS ending ([url]http://www.bc-robotics.com/shop/jst-2-pin-cable/[/url] that sort of ending) into a micro USB one so I can actually power my raspberry pi. Any idea on if this is possible and/or the best way to go about it?
turns out ENIG is really expensive so my nametag will cost me 45€! Worth it.
[QUOTE=Guzbone;41867570]So, I'm new to this whole electrical engineering thing and I haven't started yet really but I have a project in mind. I'm using a Raspberry Pi as my base to be a main hub controller thing.
My main question here is this though. I'm looking to power my Raspberry Pi and then some motors, probably in parallel. I need to take the output of my battery which is 7.4V (2x3.7V) through a voltage regulator (5V) and then I need to turn the JS ending ([url]http://www.bc-robotics.com/shop/jst-2-pin-cable/[/url] that sort of ending) into a micro USB one so I can actually power my raspberry pi. Any idea on if this is possible and/or the best way to go about it?[/QUOTE]
Just use a 7805 and splice on a usb plug, shouldn't be too hard.
Just make sure you hooked it up correctly and that it is in fact outputting 5v with a multimeter before you even think about plugging it into the raspPi.
A better solution would be a dc-dc converter because the 7805 will conk out when the voltage of the batteries goes below the dropout voltage, probably about 6-6.5 volts. You could use a low dropout regulator that will work until maybe 5.5 volts but a buck-boost dc-dc converter can work below a battery voltage of 5 volts, though at that point your batteries will be dead anyways (~<2.5V per cell equals dead lithium-ion cells). The major reason to use a dc-dc converter is that a 7805 just pisses away the extra voltage as heat and thus will drain the batteries faster, whereas a dc-dc converter will be 80-95% efficient.
Edit:
Also, are your batteries protected or unprotected cells? It won't matter much when using a 7805 because it will drop out and the pi will turn off before you risk damaging your batteries by over discharge so you'll know when to charge them, but just wondering.
[QUOTE=DrDevil;41869165]turns out ENIG is really expensive so my nametag will cost me 45€! Worth it.[/QUOTE]
Put the copper layer from a random PCB as the background and then put your letters on top of that as copper fill - then you'll have cool circuit-boardy patterns under the solder mask :v:
[QUOTE=r0b0tsquid;41869425]Put the copper layer from a random PCB as the background and then put your letters on top of that as copper fill - then you'll have cool circuit-boardy patterns under the solder mask :v:[/QUOTE]
I wanted to keep it simple!
[QUOTE=chipset;41869349]Just use a 7805 and splice on a usb plug, shouldn't be too hard.
Just make sure you hooked it up correctly and that it is in fact outputting 5v with a multimeter before you even think about plugging it into the raspPi.
A better solution would be a dc-dc converter because the 7805 will conk out when the voltage of the batteries goes below the dropout voltage, probably about 6-6.5 volts. You could use a low dropout regulator that will work until maybe 5.5 volts but a buck-boost dc-dc converter can work below a battery voltage of 5 volts, though at that point your batteries will be dead anyways (~<2.5V per cell equals dead lithium-ion cells). The major reason to use a dc-dc converter is that a 7805 just pisses away the extra voltage as heat and thus will drain the batteries faster, whereas a dc-dc converter will be 80-95% efficient.
Edit:
Also, are your batteries protected or unprotected cells? It won't matter much when using a 7805 because it will drop out and the pi will turn off before you risk damaging your batteries by over discharge so you'll know when to charge them, but just wondering.[/QUOTE]
I very much intend to check everything before I use it with any of my parts that can actually be damaged by it, my brief playing with electricity in the past ended in a hurry when I tried to hook up a 9V battery to an LED, you'd never guess what happened.
So if I get something like [url]http://www.adafruit.com/products/1065[/url] then you just put it between the battery and the raspPi on the positive line? Also I've looked into the whole splicing on a usb plug and it seems quite easy, I have this issue where I always imagine things to do with electrical engineering to be more difficult than they really are and seemingly impossible. Need to remember you can jerry rig anything just about.
[url]http://www.bc-robotics.com/shop/lithium-ion-battery-pack-6600mah/[/url] Is what I'm looking into maybe getting for my batteries, two of them like I said, should be more than enough power for what I'm doing but I figure I can use them for other projects as well if I treat them nice.
[QUOTE=Guzbone;41869767]I very much intend to check everything before I use it with any of my parts that can actually be damaged by it, my brief playing with electricity in the past ended in a hurry when I tried to hook up a 9V battery to an LED, you'd never guess what happened.
So if I get something like [url]http://www.adafruit.com/products/1065[/url] then you just put it between the battery and the raspPi on the positive line? Also I've looked into the whole splicing on a usb plug and it seems quite easy, I have this issue where I always imagine things to do with electrical engineering to be more difficult than they really are and seemingly impossible. Need to remember you can jerry rig anything just about.
[url]http://www.bc-robotics.com/shop/lithium-ion-battery-pack-6600mah/[/url] Is what I'm looking into maybe getting for my batteries, two of them like I said, should be more than enough power for what I'm doing but I figure I can use them for other projects as well if I treat them nice.[/QUOTE]
I would advise against buying from adafruit, sparkfun, makershed, radioshack or any other sites aimed at makers as they are generally extremely overpriced. That dc-dc converter module you linked probably costs adafruit $0.5 a piece from the supplier. Try more professional sites like digikey, farnell, mouser etc. They are all great but shipping might be expensive (you'll have to check it out, not sure) and their sites are enormous and challenging to navigate but the parts are dirt cheap as they generally deal in quantities of thousands. For small orders I buy my components from [url]www.bitsbox.co.uk[/url] but they don't ship to north america, I'm pretty sure you can order from farnell.com with free shipping in the USA, not sure about canada. As I'm european I can't really help you much with retailers but ebay is always an option.
Loads of chinese sellers have free shipping and dirt cheap parts, but they are sometimes counterfeit parts. See if you can find any canadian or american ebay electronics sellers.
Oh, and check these out: [url]http://www.ebay.ca/itm/DC-DC-Boost-Buck-Converter-Step-Up-Step-Down-Supply-Module-3-35V-to-2-2-30V-S5-/251316934129?pt=LH_DefaultDomain_0&hash=item3a83a815f1&_uhb=1[/url]
Dirt cheap dc-dc buck boost modules, all you have to do is hook up the batteries at one end, twiddle the potentiometer to get 5 volts out and connect the pi in the other end. They're from china though so expect 3-4 weeks shipping time.
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