[QUOTE=DrLuckyLuke;40013392]Or use a diffusor (thin paper)[/QUOTE]
Exactly my plan, combined with keeping a distance between the LED's, the diffuser and the PCB.
[t]http://i.imgur.com/CvMVr3K.png[/t]
Latest update to my active load, I've removed the BJTs since they're highly inefficient at such high currents and made several other changes to improve
stability thanks to the eevblog forum, it turns out the most expensive part is going to be the case, high current connectors and the display which will be
either VFD or character LCD (leaning towards VFD).
Ddrl is handling most of the digital design since I'm a complete noob at anything not analog, so pump him if you want more info.
Here's some close-up porn shots
[img]http://i.imgur.com/2ooAIbw.jpg[/img]
[img]http://i.imgur.com/bTpaBXT.jpg[/img]
I totally fucked up this board. It doesn't even work because half of the traces were damaged when i was struggling to get the board out of the etching solution using scissors.
[QUOTE=alexaz;40020770]Here's some close-up porn shots
[img]http://i.imgur.com/2ooAIbw.jpg[/img]
[img]http://i.imgur.com/bTpaBXT.jpg[/img]
I totally fucked up this board. It doesn't even work because half of the traces were damaged when i was struggling to get the board out of the etching solution using scissors.[/QUOTE]
Oh my....
You monster.
[QUOTE=alexaz;40020770]Here's some close-up porn shots
I totally fucked up this board. It doesn't even work because half of the traces were damaged when i was struggling to get the board out of the etching solution using scissors.[/QUOTE]
use insulated wire to rig a holder, and put the PCB into it. The end of the holder should stick out of the solution so you can easily pick it up.
[QUOTE=alexaz;40020770]Here's some close-up porn shots
[url]http://i.imgur.com/2ooAIbw.jpg[/url]
[url]http://i.imgur.com/bTpaBXT.jpg[/url]
I totally fucked up this board. It doesn't even work because half of the traces were damaged when i was struggling to get the board out of the etching solution using scissors.[/QUOTE]
Should've drilled a hole in a corner with no traces before dunking it in the etching solution.
Then you could easily tie a insulated wire in that hole or just a piece of string (although the etchant will slowly crawl up a non synthetic string.
[img]http://i.imgur.com/3jbEPCA.png[/img]
So i made my a board for this. It does work but i have no idea what the fuck its doing.
1) Even tho the voltage divider has the ratio of 0.075 (R1=46.73k and R2=2.3k or smth) the opamp doesn't try to even the voltages out, and seems like for every volt from the DAC i get 3.4 volts output.
2) The voltage significantly drops when i apply a load. This regulator isn't really doing what its supposed to.
To have an N-Channel MOSFET on the high side, you need a higher drive voltage to be able to completely saturate it (turn it on). You'd ideally need something about 13.5V.
It appears the upper regulator sets the drain voltage of Q2 while the lower regulator sets the current where the current is proportional to Vset / R3.
The connector pins thus would be:
1 - Voltage feedback
2 - Voltage set
3 - ground
4 - Current set (V / R3)
5 - Current feedback (Vset / R3)
So to answer question 1 the voltage divider is way too big, with the values you gave me the feedback voltage would only 0.5V at 12V supply voltage, I assume your trying to set it with 0-5V which is too large a range for you to get a small step from the DAC (depending on the amount of bits), for 12V I suggest a divider ratio of 3 which will give you 4V (6.8k & 3.3k will do the job for R1, R2).
As for question 2 I assume your connecting your load in the place of R3 where it should be, the voltage may drop of the input to the current regulator is too low, you might ask how you calculate the resistance then for determining the relationship of the current feedback voltage (V = I * R3) to the current set voltage (I = Vset / R3), you can do this quite simply by feeding the voltage and current sense voltage into an analog loop or a microcontroller and calculating the equivalent load resistance from (R3 = Vsense / Isense).
I chose the following divider ratio since my plan is to use it with a 19-20V supply and have the ADC reference at 1V5 since the drop across shunt resistor will only reach 1.5V at ~7 amps ( i only intend 3 amps max).
For some reason i connected the load inbetween the mosfets, i will try to wire it before the shunt. Thanks for the help.
Well fuck, turns out i really need a drive voltage for the high-side switch.
So I picked up an old turn table at a thrift-store for $15 a couple weeks ago. The tone-arm wiring was shorting out but that was an easy fix. There's still some issues, mainly due to the head-shell socket connector not making good contact with the headshell. I need to essentially replace the head-shell socket.
Today my package for my digitally timecoded vinyl came in today and I decided to give it a try to rig it to see if I could get it to work. Much to my surprise, it works!
You're supposed to use a preamp on the phono, but software amplification seems to work though it's pretty noisy.
Here's a video showing it working:
[media]http://www.youtube.com/watch?v=VOIlWa89b84[/media]
Sorry for my slow... stuttery speech, it's been a long day.
My EEPROM's failing to program a couple of specific addresses, seems to be faulty :( can not find the same part anywhere!
[QUOTE=r0b0tsquid;40048576]My EEPROM's failing to program a couple of specific addresses, seems to be faulty :( can not find the same part anywhere![/QUOTE]
Aren't there any pin compatible eeproms? usually they all follow the same pin layout
Welp, it's fucked :v:
[QUOTE=DrLuckyLuke;40048900]Aren't there any pin compatible eeproms? usually they all follow the same pin layout[/QUOTE]
The only ones I can find are 150ns, I need a 70ns to run at full speed. Luckily I have a half megabyte parallel flash chip with a 70ns access time... I was planning to use it for mass storage, it's really cheap to get another though.
It's gonna take a bit of wiring, 2 rows bigger than the original and slightly different address layout, glad I left space in my layout!
[editline]blah[/editline]
It's getting really hard to find DIP EEPROMs, luckily flash DIPs can still be had fairly easily from a few places
[t]http://i.imgur.com/elHjGYu.jpg[/t]
All my why.
wha happened?
Everyone remembers those cheap USBASP programmers. Yeah, so if you by the Lcsoft v2.0 or Hobby King versions of them, you better be prepared to upgrade their firmware before you use it.
Finally got mine working today, it was a mixture of a bad ISP cable and old firmware. Thankfully my old serial port programmer still worked like a champ when I rinse-n-repeat soldered it to the ISP header on the USBASP stick.
[img_thumb]http://oi49.tinypic.com/2lcyd1j.jpg[/img_thumb]
Also, I found this useful for upgrading the firmware:
[URL="http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=1041690"]http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=1041690[/URL]
[t]http://i.imgur.com/d0G0n9q.jpg[/t]
New chip in place, all the orange/blue wiring is new/replaced.
Apparently I need 5 and 12 volts to program it and there are commands and stuff instead of just a WE pulse and whaaa been at a funeral all day don't need this shit, off to bed it's late
[editline]26th March 2013[/editline]
Not even slightly tested
[QUOTE=LoneWolf_Recon;40051127]Everyone remembers those cheap USBASP programmers. Yeah, so if you by the Lcsoft v2.0 or Hobby King versions of them, you better be prepared to upgrade their firmware before you use it.
Finally got mine working today, it was a mixture of a bad ISP cable and old firmware. Thankfully my old serial port programmer still worked like a champ when I rinse-n-repeat soldered it to the ISP header on the USBASP stick.
[img_thumb]http://oi49.tinypic.com/2lcyd1j.jpg[/img_thumb]
Also, I found this useful for upgrading the firmware:
[URL="http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=1041690"]http://www.avrfreaks.net/index.php?name=PNphpBB2&file=viewtopic&p=1041690[/URL][/QUOTE]
Exactly the reason why I prefer to pay a few bucks more and thus have firmware updating over USB
[QUOTE=DrLuckyLuke;40051929]Exactly the reason why I prefer to pay a few bucks more and thus have firmware updating over USB[/QUOTE]
Using what system? The USBASP's cant be upgraded themselves without a secondary programmer.
[QUOTE=LoneWolf_Recon;40052082]Using what system? The USBASP's cant be upgraded themselves without a secondary programmer.[/QUOTE]
ISP MkII clones. They support Atmel's flip bootloader.
[QUOTE=r0b0tsquid;40049566]It's getting really hard to find DIP EEPROMs[/QUOTE]
TSSOP EEPROM's on DIP adapter boards.
So yesterday i sort of finished my RGB LED shelf thing. Its quite simple and cheap ( would have been cheaper if i had ordered the LED's from China, but i was too impatient and ordered them from Farnell)
Its based of 4 boards, which are mostly just "adapters" for IC's.
Top left board is just a part of a broken launchpad with a MSP430G2553 chip in it.
Bottom left is a switching 5V to 3V3 regulator.
Top right is a TLC5925IDWR LED driver breakout ( just a more beefy current sinking shift register )
Bottom right is a MCP2200 USB to serial breakout for the control of LED's.
[t]http://i.imgur.com/CJqW0Lm.jpg[/t]
Each LED's colors are controllable with 32 step PWM ( i guess i could go higher, but its hard to balance the PWM and serial because of how shit the current code is). My initial plan was to go with the PCA9622DR I2C LED driver, but it was my first time soldering a TSSOP and it ended up like this:
[t]http://i.imgur.com/IsyEoCy.jpg[/t]
The total cost was around maybe 30$.
[t]http://i.imgur.com/yWSsz5K.jpg[/t]
[t]http://i.imgur.com/J4WtUIn.jpg[/t]
I finally sorted out transitioning my keyboard from the Leostick to my new Teensy++ 2.
I was having a lot of issues, getting bogus data and having it spam unwanted keystrokes to the point that I was scared to plug it in while I had any code open. Turned out I had just forgotten to connect the pull down resistors to ground, resulting in a tonne of false positives.
In celebration of this new microcontroller setup, I decided I was going to make it a little more neat. So I went out and got my first every protoboard.
[t]https://dl.dropbox.com/u/62766551/Norseboard/9549_10200328012295613_893067645_n.jpg[/t]
The whole underside is quite untidy and a little scary, but I've since put a strip of electrical tape over it, so you can't even tell what lies beneath.
From the top though, it looks really neat and makes my life a million times easier.
[t]https://dl.dropbox.com/u/62766551/Norseboard/P3280076-2.jpg[/t]
I got some female headers, which allows me to detach the microcontroller and keyboard matrix, making it very easy if I want to borrow the microcontroller for something or take the keyboard somewhere.
Stolen from funny pics
[t]http://i.imgur.com/PDuz5YR.jpg[/t]
Arduino at it's full potential. I wonder what it does when someone inevitably puts their penis into it.
Some pictures inside of an old Canon Servo EE Finder (automatically adjusts the aperture of the camera lens).
[url=http://i.imgur.com/cvNnUMz.jpg][img]http://i.imgur.com/cvNnUMzl.jpg[/img][/url]
[url=http://i.imgur.com/496TBy5.jpg][img]http://i.imgur.com/496TBy5l.jpg[/img][/url]
[url=http://i.imgur.com/KxxMu3a.jpg][img]http://i.imgur.com/KxxMu3al.jpg[/img][/url]
Few more at [url]http://imgur.com/a/1hplj[/url]
Edit:
And some silly video of it running:
[media]http://www.youtube.com/watch?v=MtChoyVx8q0[/media]
[QUOTE=Tw34k;40070394]Stolen from funny pics
[t]http://i.imgur.com/PDuz5YR.jpg[/t]
Arduino at it's full potential.[B] I wonder what it does when someone inevitably puts their penis into it.[/B][/QUOTE]
[img]http://mchelsea22.files.wordpress.com/2010/02/guillotine.jpg[/img]
[QUOTE=Tw34k;40070394]Stolen from funny pics
[t]http://i.imgur.com/PDuz5YR.jpg[/t]
Arduino at it's full potential. I wonder what it does when someone inevitably puts their penis into it.[/QUOTE]
It weeps silently.
No doubt many of you have already seen it, but in the same vein, the Signetics Random Access Write Only Memory:
[url]http://portal.national.com/rap/files/datasheet.pdf[/url]
With a bit of background here: [url]http://portal.national.com/rap/Story/WOMorigin.html[/url]
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