Electrical Engineering V2 - Developers

[QUOTE=DrDevil;44133217]Don't, you'll most likely kill yourself or set your house on fire.[/QUOTE] [url]http://hackaday.com/2012/12/18/244-9-volt-batteries-in-series-arcing-ensues/[/url] he doesn't seem to have that problem.

[QUOTE=maxb130;44135574][url]http://hackaday.com/2012/12/18/244-9-volt-batteries-in-series-arcing-ensues/[/url] he doesn't seem to have that problem.[/QUOTE] Well, whatever you do, you should have both a fireextinguisher and a second person handy, just in case anything happens.

[QUOTE=Varsatorul;44134973]Who wants to see some gore? NSFL [IMG]http://i.imgur.com/rrdcCqKl.jpg[/IMG] [IMG]http://i.imgur.com/PeEzvm5l.jpg[/IMG][/QUOTE] Judging by the second picture it doesn't seem that you use flux. Most likely you are using the wrong type of solder. Get the one that has a rosin core. (or i just can't see the flux)

I can see the flux, it just appears that way too much solder has been applied, it should not form a ball. Also use leaded solder it flows much easier. Turn the temperature down as well, if you see the flux turning black it's too hot and it won't have time to do its job properly. Make sure your iron tip makes contact with the pad and lead, just touching the lead will often form a cold solder joint. The tip looks a little black, apply solder and wipe until it's a nice silver color. Use the thinnest solder you can get, at least 0.5mm for more control over the amount of solder you apply Avoid really cheap solder as it often has uneven or poor flux content, I use [url=http://www.conrad-electronic.co.uk/ce/en/product/812803/Stannol-Solder-wire-for-electronics-engineering-DiameterSpool-NA]this[/url] which works great. And most importantly [b]Buy a good soldering station.[/b]

[QUOTE=Chryseus;44135704]I can see the flux, it just appears that way too much solder has been applied, it should not form a ball. Also use leaded solder it flows much easier. Turn the temperature down as well, if you see the flux turning black it's too hot and it won't have time to do its job properly. Make sure your iron tip makes contact with the pad and lead, just touching the lead will often form a cold solder joint. The tip looks a little black, apply solder and wipe until it's a nice silver color. Use the thinnest solder you can get, at least 0.5mm for more control over the amount of solder you apply Avoid really cheap solder as it often has uneven or poor flux content, I use [url=http://www.conrad-electronic.co.uk/ce/en/product/812803/Stannol-Solder-wire-for-electronics-engineering-DiameterSpool-NA]this[/url] which works great. And most importantly [b]Buy a good soldering station.[/b][/QUOTE] Thank you, I appreciate your advice!

[QUOTE=alexaz;44125006]How do you fry the chip if its shorted from VCC to ground? You only shorted the power rail and there was no power flowing through the chip.[/QUOTE] Ah I described that poorly. I shorted the reset pin which was at +12V to the output pin which can act as a sink to ground. The problem was this 555 in particular is only rated to sink 200mA through that pin and the 1 amp or so I shorted through it burned it out.

Little wireless video test rig I built for experimenting with antennas and such. 1.2GHz 1500mW (allegedly) [t]http://i.imgur.com/JktFoQe.jpg[/t] [t]http://i.imgur.com/PwmZb4r.jpg[/t] With the linear polarized monopole antennas that come with the RX/TX I'm managing to get over 500 ft range going through all sorts of walls, buildings, trees, etc. Now to build a Yagi...

[QUOTE=Disco_Potato;44161974]Little wireless video test rig I built for experimenting with antennas and such. 1.2GHz 1500mW (allegedly) [t]http://i.imgur.com/JktFoQe.jpg[/t] [t]http://i.imgur.com/PwmZb4r.jpg[/t] With the linear polarized monopole antennas that come with the RX/TX I'm managing to get over 500 ft range going through all sorts of walls, buildings, trees, etc. Now to build a Yagi...[/QUOTE] Is 1.5 watts legal? I thought 1 watt is the max.

Without a HAM license I think the limit is only 10mW in the US, in the 23cm band.

There's different bands with different power limits in different countries.

Gonna go on the record and say that Digistumps are some of the most adorable ucontroller setups: [img_thumb]http://oi62.tinypic.com/2ilcyhd.jpg[/img_thumb] I think I'll setup this one as a usb-thumb-drive-sized data acquisition device.

I need a bigger workbench [url=http://i.imgur.com/VHwtn8Y.jpg][img]http://i.imgur.com/VHwtn8Yl.jpg[/img][/url]

Hey... i have a problem with gears.... Im looking for some steel gears... around a 1:20 ratio, the smaller gear having an ID of 5mm, the larger one's ID is irrelevent. ideally the larger gear needs to have a OD of around 80-100mm this is for the base of a robot arm im designing that will be similar to the kuka style robot.... I have been searching for some time and have been unable to come up with a reasonable priced set of gears :/

[QUOTE=nuttyboffin;44170666]Hey... i have a problem with gears.... Im looking for some steel gears... around a 1:20 ratio, the smaller gear having an ID of 5mm, the larger one's ID is irrelevent. ideally the larger gear needs to have a OD of around 80-100mm this is for the base of a robot arm im designing that will be similar to the kuka style robot.... I have been searching for some time and have been unable to come up with a reasonable priced set of gears :/[/QUOTE] What gears have you been looking at?

[QUOTE=Zero-Point;44171039]What gears have you been looking at?[/QUOTE] Usually on gear website in the UK, most of the gears end up looking to be around £40.... Ideally, i would like somthing like this: [img]http://capolight.files.wordpress.com/2011/01/internal-gear.jpg[/img] But i would have more chance getting somthing like this: [img]https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTVNetQGY65wIYAa_m_22nQ3cOCUxsBdyIDP2aeMjGIh0WQNgDsMg[/img] The larger gear would be screwed and bolted down to the base while the smaller one goes on a motor to rotate the whole thing.

Was about to link you to [url]http://www.mcmaster.com/[/url] , but I doubt you'd be interested in international shipping.

[QUOTE=Disco_Potato;44162750]Without a HAM license I think the limit is only 10mW in the US, in the 23cm band.[/QUOTE] Who cares. It's only senile fucks and elitists who would try and report you. Run packet over CB to piss them off.

[QUOTE=Angus725;44171378]Was about to link you to [url]http://www.mcmaster.com/[/url] , but I doubt you'd be interested in international shipping.[/QUOTE] Yeh, im afraid not, sorry >_<

[QUOTE=nuttyboffin;44171124]Usually on gear website in the UK, most of the gears end up looking to be around £40.... Ideally, i would like somthing like this: [img]http://capolight.files.wordpress.com/2011/01/internal-gear.jpg[/img] But i would have more chance getting somthing like this: [img]https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTVNetQGY65wIYAa_m_22nQ3cOCUxsBdyIDP2aeMjGIh0WQNgDsMg[/img] The larger gear would be screwed and bolted down to the base while the smaller one goes on a motor to rotate the whole thing.[/QUOTE] I actually have some gears like those on the bottom, but I'd have to dig them out from who-knows-where-they-are-now. One steel, one some sort of composite plastic. The drive gears are embedded on the motor shafts though, and ironically enough they also came from old robotic arms a friend of my dad's scored from a university's auction left-overs. (though I wholly regret receiving them in my young-and-stupid age where I dismantled all four arms)

Old printers.

I'm trying to make a voltage multiplier but not having much luck yet, was wondering if you guys have any tips. I have an arduino providing a 50Hz half square wave (turning a pin on and off at 50Hz), running through a 2n2222 transistor. I've checked this works with an LED so that part definitely seems to be ok. I've then tried to recreate this: [img]http://sub.allaboutcircuits.com/images/03288.png[/img] Here is my version: [img]http://i.imgur.com/gA0d5DL.jpg?1?5068[/img] The red wire is coming off the positive terminal of a 12v battery, the green wire goes to the collecter of the transistor. The capacitors are 472M 2Kv. I would expect the terminal one the right to be at 96V, right? I've tried measuring it by putting one end of a multimeter at the end terminal and one to ground, but got 0V. Also tried connecting the terminal to ground and seeing if it sparked but nothing happened, so I'm fairly sure something is amiss - maybe the entire idea! Thanks for any help! :smile: EDIT images of the rest of it: [url]http://i.imgur.com/yeHcyMT.jpg[/url] [url]http://i.imgur.com/3QVuktR.jpg[/url]

[QUOTE=chaz13;44172841]I'm trying to make a voltage multiplier but not having much luck yet, was wondering if you guys have any tips. I have an arduino providing a 50Hz half square wave (turning a pin on and off at 50Hz), running through a 2n2222 transistor. I've checked this works with an LED so that part definitely seems to be ok. I've then tried to recreate this: [img]http://sub.allaboutcircuits.com/images/03288.png[/img] Here is my version: [img]http://i.imgur.com/gA0d5DL.jpg?1?5068[/img] The red wire is coming off the positive terminal of a 12v battery, the green wire goes to the collecter of the transistor. The capacitors are 472M 2Kv. I would expect the terminal one the right to be at 96V, right? I've tried measuring it by putting one end of a multimeter at the end terminal and one to ground, but got 0V. Also tried connecting the terminal to ground and seeing if it sparked but nothing happened, so I'm fairly sure something is amiss - maybe the entire idea! Thanks for any help! :smile: EDIT images of the rest of it: [url]http://i.imgur.com/yeHcyMT.jpg[/url] [url]http://i.imgur.com/3QVuktR.jpg[/url][/QUOTE] That well not work as you need a +12v -12v swing. You should have the ground.. to ground, then have the part you have connected to +12v to swing between +12v and -12v Try this circuit i just made up: [img]http://i.imgur.com/myyFjj3.png[/img] You should be honored, i just spent my time drawing that up instead of working on my 6 axis robot design: [img]http://i.imgur.com/LRqdMuN.png[/img]

Thanks for taking the time out to help me out, I get the gist of what I need to do now and I'll give your circuit a shot. Out of curiosity, is it possible to just connect a negative voltage of half the amplitude of the square wave to my current square wave output to shift it all down, making it vary from + to - 6v? Or use a capacitor to remove the theoretical DC offset? That seems doable and a lot simpler but I assume that doesn't work for some reason :v:

[QUOTE=chaz13;44174169]Thanks for taking the time out to help me out, I get the gist of what I need to do now and I'll give your circuit a shot. Out of curiosity, is it possible to just connect a negative voltage of half the amplitude of the square wave to my current square wave output to shift it all down, making it vary from + to - 6v? Or use a capacitor to remove the theoretical DC offset? That seems doable and a lot simpler but I assume that doesn't work for some reason :v:[/QUOTE] not tooo sure, but this method would be the most likely to work and also most likely to last :P It also means you learn some more~

I don't have time to set up my crappy oscilloscope now but I'll mess about with a few different ways tomorrow and see what works.. thanks for the tips! I'm intrigued by the coupling capacitor idea. In theory it should remove the DC offset (I think..), but I don't get conceptually how it'd suddenly generate a negative voltage.

What about using a computer PSU? That should give you -12, -5, 0, +5, and +12.

[QUOTE=chaz13;44174351]I don't have time to set up my crappy oscilloscope now but I'll mess about with a few different ways tomorrow and see what works.. thanks for the tips! I'm intrigued by the coupling capacitor idea. In theory it should remove the DC offset (I think..), but I don't get conceptually how it'd suddenly generate a negative voltage.[/QUOTE] Another option is setting up an H-bridge or something similiar, to where you can swap which rail the 12V/Gnd is connected to. That coupled with the correct interface circuitry (Buffer Op Amps perhaps) and some software shenanigans to create a[URL="http://www.csulb.edu/~hill/ee470/Lab%202d%20-%20Sine_Wave_Generator.pdf"] sine wave with PWM.[/URL]

[QUOTE=nuttyboffin;44173171] You should be honored, i just spent my time drawing that up instead of working on my 6 axis robot design: [img]http://i.imgur.com/LRqdMuN.png[/img][/QUOTE] What program are you making that in?

[QUOTE=LoneWolf_Recon;44175668]Another option is setting up an H-bridge or something similiar, to where you can swap which rail the 12V/Gnd is connected to. That coupled with the correct interface circuitry (Buffer Op Amps perhaps) and some software shenanigans to create a[URL="http://www.csulb.edu/~hill/ee470/Lab%202d%20-%20Sine_Wave_Generator.pdf"] sine wave with PWM.[/URL][/QUOTE] Thats more or less what i just set up, a half-bridge, but i replaced the capacitors with the center terminal of 2 9v batterys. [editline]9th March 2014[/editline] [QUOTE=Gulen;44177648]What program are you making that in?[/QUOTE] Solid Edge, downloaded the educational version instead of paying £6000, i got taught at my work experiance, but for most of the time i followed the tutorials built in and asked one of the staff. Really good software, has craploads of features and loads of really cool things... totally would buy it if i had the money

9v batteries have center terminals?