So I went to Radioshack the other day to finally pick up an Ethernet shield.
I now have a serial IRC client. I plan on expanding it into a bot.
Hey guys, I would like some help.
I'm going to need to control the power of a motor from a 12V Dewalt power drill.
I'll be using my Arduino, but I have no idea what I should get, I've been searching for some transistors, but I find it really hard to find something that'll do. Please help :smile:
[QUOTE=AGMadsAG;33314097]Hey guys, I would like some help.
I'm going to need to control the power of a motor from a 12V Dewalt power drill.
I'll be using my Arduino, but I have no idea what I should get, I've been searching for some transistors, but I find it really hard to find something that'll do. Please help :smile:[/QUOTE]
Really big-ass FETs or BJTs with heatsinks.
If you need it to run both directions, then you need H-bridge chips too.
Check the power requirements of the drill (it's probably a few amps) and cross-reference with the transistor datasheets. You need to make sure that:
1. They can handle the sustained current
2. The power dissipation is within the specified limit. The power dissipation should be something like I^2*R_DS for a MOSFET in a common-emitter configuration.
For things like motors you also need big power transistors in parallel with the load to short back-EMF across either the motor itself or to V+/ground. Without these it will destroy all your control electronics.
-snip- ups :v:
So I just started my Electronics course at University 6-7 weeks ago. I'm really liking the embedded programming stuff but I'm really not enjoying the other stuff, such as analogue circuit design which seems to make up the majority of the course
I keep looking at the computer science course and wondering if I'll prefer that. Could you guys give any advice? What kind of job could I get with an Electronics Engineering degree? I know you're probably thinking I should have done all this research before and I did but I probably had the wrong idea of what electronic engineers actually do.
Are there many jobs out there for us that don't involve calculating resistors and capacitors and analogue things like that?
Thanks
[QUOTE=Zeonho;33314520]still the same frame rate but every sprite has a tintcolor now
[img]http://dl.dropbox.com/u/28308500/Pics/vbotest.png[/img][/QUOTE]
Wrong thread?
[QUOTE=Zeonho;33314520]still the same frame rate but every sprite has a tintcolor now
[img]http://dl.dropbox.com/u/28308500/Pics/vbotest.png[/img][/QUOTE]
Wrong thread :v:
[editline]17th November 2011[/editline]
[QUOTE=Trumple;33314550]So I just started my Electronics course at University 6-7 weeks ago. I'm really liking the embedded programming stuff but I'm really not enjoying the other stuff, such as analogue circuit design which seems to make up the majority of the course
I keep looking at the computer science course and wondering if I'll prefer that. Could you guys give any advice? What kind of job could I get with an Electronics Engineering degree? I know you're probably thinking I should have done all this research before and I did but I probably had the wrong idea of what electronic engineers actually do.
Are there many jobs out there for us that don't involve calculating resistors and capacitors and analogue things like that?
Thanks[/QUOTE]
I honestly think you're crazy. Analog is all the really fun stuff!
You could probably get away with Computer Engineering. It's more logic-y than EE. More block diagrams, fewer transforms to the s-domain. You'd still have to take some EE though, as CpE and EE have a lot of overlap.
But if you [i]really[/i] don't like that sort of math, go CS. Any engineering discipline is going to be a lot of calculus and hard natural sciences.
[QUOTE=ROBO_DONUT;33314581]
I honestly think you're crazy. Analog is all the really fun stuff!
[/QUOTE]
It's not it just sits there and looks boring :(
You're honestly interested by potential dividers and other passive components?
Maybe I'm not cut out for this :(
[QUOTE=ROBO_DONUT;33313856]I went to the RadioShack at the local mall (which used to be the absolute [i]worst[/i]) and suddenly they stock heatsinks, mica insulators, and aluminum project boxes, among other things.
Just a few months ago I'd go there and find nothing but iPod accessories in the component drawers.[/QUOTE]
I used to call it "The Sprint Store" because they didn't even sell common logic chips anymore, and only a handful of analog chips like LM339s and NE555s, but HOLY JEBUS did they have PHONES!
[QUOTE=Trumple;33314719]It's not it just sits there and looks boring :(
You're honestly interested by potential dividers and other passive components?
Maybe I'm not cut out for this :([/QUOTE]
Certainly!
You can't have high-voltage boost converters without inductors. I'd say it gets really interesting, though, when you get to semiconductors. Bandgaps, quasi-Fermi levels, amplifiers and all that good shit.
Remember, though, you're still in your first year. At least here, it's mostly fundamental math and interdisciplinary stuff for the first two years. You don't get into the really serious stuff for your specific major until your fourth or fifth semesters.
[QUOTE=ROBO_DONUT;33314879]though, when you get to semiconductors. Bandgaps, quasi-Fermi levels, amplifiers and all that good shit.
[/QUOTE]
We've just gone through all that and I found it really dull :(
[QUOTE=Trumple;33314719]It's not it just sits there and looks boring :(
You're honestly interested by potential dividers and other passive components?
[/QUOTE]
Things like building a tuned amplifier so it only amplifies certain frequencies or working out the time constants of capacitors as part of a precision oscillator are some of life's small pleasures. Look at this way, a micro, CPLD or the like are great, sure, but when you can solve a problem with a bunch of components costing less than the chip, surely that's a win?
[QUOTE=Trumple;33314905]We've just gone through all that and I found it really dull :([/QUOTE]
EE probably isn't for you, then.
[QUOTE=ROBO_DONUT;33314948]EE probably isn't for you, then.[/QUOTE]
I wonder if it's too late to change course...
But then what about all the digital stuff? I like that...maybe I could become an embedded systems programmer or something...
[QUOTE=Trumple;33314980]I wonder if it's too late to change course...
But then what about all the digital stuff? I like that...maybe I could become an embedded systems programmer or something...[/QUOTE]
You don't have a Computer Engineering curriculum?
Still, though, if you can't enjoy the simple stuff, I'm not sure that you're going to enjoy any engineering discipline.
[QUOTE=Trumple;33314550]So I just started my Electronics course at University 6-7 weeks ago. I'm really liking the embedded programming stuff but I'm really not enjoying the other stuff, such as analogue circuit design which seems to make up the majority of the course
I keep looking at the computer science course and wondering if I'll prefer that. Could you guys give any advice? What kind of job could I get with an Electronics Engineering degree? I know you're probably thinking I should have done all this research before and I did but I probably had the wrong idea of what electronic engineers actually do.
Are there many jobs out there for us that don't involve calculating resistors and capacitors and analogue things like that?
Thanks[/QUOTE]
I'm in my third year of mechanical engineering / computer science, so I've only been exposed to the basics for electronics. I enjoyed it, but I think mechanical or aerospace is my discipline of choice (my uni doesn't offer aerospace sadly...)
You're only a month or two in, so don't stress! You're probably mostly studying stuff right now that you'd need to be doing for any engineering, and you should figure out what you enjoy most as you get exposed to more. A friend of mine did a year of engineering, hated it then switched to computer science which seems to be going really well for him now.
If you're tossing up whether you'd enjoy computer science or software engineering and your course allows it, you might as well enrol in a few things from those areas and try it out. I love studying maths and all the theory for mech, but I really enjoy the creative side of computer science, so studying both was a great choice for me.
Also, mechatronic engineering could be something you'd be interested in - bits of mechanical, exposed to electronics but also some programming and control.
[QUOTE=Trumple;33314980]I wonder if it's too late to change course...
But then what about all the digital stuff? I like that...maybe I could become an embedded systems programmer or something...[/QUOTE]
Designing good digital circuits and to some extent programming them requires a good knowledge of analog electronics, digital signals are after all fundamentally analog and you need to understand concepts like rise / fall time, propagation delay, clock skew, impedance, filters, etc.
I suggest you consider doing a different course.
[QUOTE=Little Green;33315602]I'm in my third year of mechanical engineering / computer science, so I've only been exposed to the basics for electronics. I enjoyed it, but I think mechanical or aerospace is my discipline of choice (my uni doesn't offer aerospace sadly...)
You're only a month or two in, so don't stress! You're probably mostly studying stuff right now that you'd need to be doing for any engineering, and you should figure out what you enjoy most as you get exposed to more. A friend of mine did a year of engineering, hated it then switched to computer science which seems to be going really well for him now.
If you're tossing up whether you'd enjoy computer science or software engineering and your course allows it, you might as well enrol in a few things from those areas and try it out. I love studying maths and all the theory for mech, but I really enjoy the creative side of computer science, so studying both was a great choice for me.
Also, mechatronic engineering could be something you'd be interested in - bits of mechanical, exposed to electronics but also some programming and control.[/QUOTE]
I had a look at the next few years to come, and it actually looks more interesting. Digital circuit design, microprocessors, a bit of software design and a few optional modules from computer science which I may choose. I guess I'll just stick it out til' that stuff comes around!
[editline]17th November 2011[/editline]
[QUOTE=Chryseus;33315611] rise / fall time, propagation delay, clock skew, impedance, filters, etc.
[/QUOTE]
That stuff actually interests me, we're covering it in logic now.
[QUOTE=Trumple;33315689]That stuff actually interests me, we're covering it in logic now.[/QUOTE]
Of all things, [i]propagation delays[/i] are interesting to you?
Analog filters, modulation, etc. are boring, but monotonously adding delays is fun?
I really think you are crazy.
[QUOTE=ROBO_DONUT;33317696]Of all things, [i]propagation delays[/i] are interesting to you?
Analog filters, modulation, etc. are boring, but monotonously adding delays is fun?
I really think you are crazy.[/QUOTE]
Modulation sounds pretty interesting, though we have yet to cover it. It's not adding propagation delays, just learning why they are there and how we can overcome them by use of other gates. It's really interesting to see how such problems are solved.
Don't worry, an insane man never knows he's going insane. I know I am :v:
Does anyone know how Async transmission works?
The documentation says:
[QUOTE]The bit duration used on the I/O line is defined as an elementary time unit (etu).
A linear relationship exists between the etu on the I/O line and CLK
frequency (f).
The bit duration is known as the initial etu, and is
given by the following equation:
initial etu: 372/f seconds, where f is in Hertz[/QUOTE]
Then it says:
[QUOTE]Prior to transmission of a character, the I/O line shall be in state H.
A character consists of 10 consecutive bits (see Figure 10):
1 start bit in state L
8 bits, which comprise the data byte
1 even parity checking bit
The start bit is detected by the receiving end by periodically sampling the I/O
line. The sampling time should be less than or equal to 0.2 etu.
The number of logic ones in a character shall be even. The 8 bits of data and the
parity bit itself are included in this check but the start bit is not.
The time origin is fixed as midway between the last observation of state H and
the first observation of state L. The existence of a start bit should be verified
within 0.7 etu. Subsequent bits should be received at intervals of (n + 0.5 ±
0.2) etu (n being the rank of the bit). The start bit is bit 1.
Within a character, the time from the leading edge of the start bit to the trailing
edge of the nth bit is (n ± 0.2) etu.
The interval between the leading edges of the start bits of two consecutive
characters is comprised of the character duration (10 ± 0.2) etu, plus a
guardtime. [/QUOTE]
[IMG]http://img593.imageshack.us/img593/5554/screenshot2011111720314.png[/IMG]
I'm kind of confused how the sampling works.
According to my calculation, the etu is 0.00007568359375 second. This is 372 clock cycles on my 4.9152 MHZ oscillator. It says to sample every 0.2 etu which is 74.4, so I'm sampling the IO line every 74 clock cycles, but I'm getting no results.
Am I doing this completely wrong? Any pros here that can dumb-down the documentation for me?
[QUOTE=thisBrad;33323681]Does anyone know how Async transmission works?
The documentation says:
Then it says:
[IMG]http://img593.imageshack.us/img593/5554/screenshot2011111720314.png[/IMG]
I'm kind of confused how the sampling works.
According to my calculation, the etu is 0.00007568359375 second. This is 372 clock cycles on my 4.9152 MHZ oscillator. It says to sample every 0.2 etu which is 74.4, so I'm sampling the IO line every 74 clock cycles, but I'm getting no results.
Am I doing this completely wrong? Any pros here that can dumb-down the documentation for me?[/QUOTE]
Most MCUs have a UART that'll handle all this for you.
Also, it would help if we knew what type of device we're working with. Is it open-collector or something? If so, you need a pull-up resistor to get any meaningful information out of it.
I've never really read up on the specifications... but if you need i2c explained, I'm your man!
I really hope you have all seen this guy's youtube channel and website... probably deserves to be on the first page.
[URL]http://coremelt.net/?show=poverview[/URL]
It includes all of his diagrams, circuitry plans, and most importantly the C and assembly he uses to make the projects with. The website is great, but really compliments his youtube channel where he talks about and shows the final results.
[URL]http://www.youtube.com/user/linuxgeek81[/URL]
Ah, I love these kinds of websites where people show off their projects. Gives me a lot of inspiration. I'm thinking of building that HDD indicator project he has. I've got a whole bunch of SMD LEDs lying around here, somewhere... Should be easy with some shifters and a small micro.
I really need to fix up my own project portfolio, but I hate writing a lot of text for each project.... [url]www.digi-online.net/portfolio[/url]
Hooray, looks like I found something that has gotten quite hot.
[img_thumb]http://i.imgur.com/VQdYq.jpg[/img_thumb]
[img]http://cloudyupload.com/images/capturejhj.jpg[/img]
I'm looking for the connector that turns on the power supply, I think it is POWER CONT but I'm not sure.
also what does FAN PROT mean?
[QUOTE=marcin1337;33371326][img]http://cloudyupload.com/images/capturejhj.jpg[/img]
I'm looking for the connector that turns on the power supply, I think it it POWER CONT but I'm not sure.
also what does FAN PROT mean?[/QUOTE]
I think FAN PROT means the tachometer thingy in the fan.
Ok Shorted POWER CONT to ground, it turns it on
I FINALLY GOT A SCOPE!
I feel like I can finally get into hobby electronics now, I got it for 1000SEK, which is about $150/£95/€110 from my electronics teacher, comes with brand new probes and service manual.
[img_thumb]http://filesmelt.com/dl/0374.JPG[/img_thumb]
[img_thumb]http://filesmelt.com/dl/0383.JPG[/img_thumb]
[img_thumb]http://filesmelt.com/dl/0397.JPG[/img_thumb]
[img_thumb]http://filesmelt.com/dl/0404.JPG[/img_thumb]
[img_thumb]http://filesmelt.com/dl/0414.JPG[/img_thumb]
Bonus, something I made a few weeks ago, can't remember if I posted it.
[img_thumb]http://filesmelt.com/dl/0276.JPG[/img_thumb]
[img_thumb]http://filesmelt.com/dl/0284.JPG[/img_thumb]
This is an upgrade form my previous which my dad found, awesome as it might be (from about 1965) it's entirely useless for hobby use
[img_thumb]http://filesmelt.com/dl/0165.JPG[/img_thumb]
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