Electrical Engineering V3 - Developers

Pro-tip: Never use the fully SMD microUSB connectors. Ordered ones with two little metal legs that connect to the shield, that you can put through the board, and two little plastic pegs on both sides of the pins, that just keep it in place, in case of side-to-side movement. Had a talk about those connectors with some smarter people than me. Traditional connectors break way too easily, and they'll rip your traces off the PCB too.

[QUOTE=nikomo;48213349]Pro-tip: Never use the fully SMD microUSB connectors. Ordered ones with two little metal legs that connect to the shield, that you can put through the board, and two little plastic pegs on both sides of the pins, that just keep it in place, in case of side-to-side movement. Had a talk about those connectors with some smarter people than me. Traditional connectors break way too easily, and they'll rip your traces off the PCB too.[/QUOTE] Millspec connectors will solve all your needs! [img]http://ecx.images-amazon.com/images/I/31GyHLz7hgL.jpg[/img] [img]http://www.te.com/content/dam/te-com/images/consumer-devices/global/product-hero-rendition/pgp-micro-usb-2-0-connector.jpg[/img] [img]http://www.procustomgroup.com/wp-content/uploads/2013/03/Getac-M-Series-milspec-ethernet-usb.jpg[/img]

[thumb]http://i.imgur.com/0i4IIfX.jpg[/thumb] My dad gave me his IC collection! I can't even find the datasheets for half of them. :v:

Jesus Tap-Dancing Christ that's a score, was your dad an embedded systems EE? Also if you don't mind listing some of those part numbers, I'd be game to try and dig up the datasheets.

[QUOTE=LoneWolf_Recon;48213729]Jesus Tap-Dancing Christ that's a score, was your dad an embedded systems EE? Also if you don't mind listing some of those part numbers, I'd be game to try and dig up the datasheets.[/QUOTE] Nope, he's just doing electronics as a hobby. He's not great at it either. He managed to collect these by disassembling old stuff when he was younger. Also there's simply too much to list, i don't even know where to start.

I spent far too long trying to figure out why my gate driver wasn't shutting the MOSFET off quickly enough. [img]http://i.imgur.com/a43TDQj.jpg[/img] [img]http://i.imgur.com/LjoXOzt.jpg[/img] I completely forgot that Drain -> Source capacitance was a thing and the 1k resistor paired with the ~500pf was taking a significant portion of the switching cycle to discharge. Threw a 22 ohm resistor in there instead and it worked flawlessly. [img]http://i.imgur.com/smEwVUO.jpg[/img] Fuckin parasitics

[QUOTE=Dolton;48214291]I spent far too long trying to figure out why my gate driver wasn't shutting the MOSFET off quickly enough. [IMG]https://photos-5.dropbox.com/t/2/AADxG2QLFka2x4hocYU4vttoWztILMC2yws0uvrkRwJAGw/12/65410658/jpeg/32x32/1/_/1/2/IMG_20150715_144813.jpg/ENf04jIY5iIgASgB/jO7ubYVpsNrEekmnl_Hh5Lp6Xy-8c-sCD74i7BHA-mA?size=1600x1200&size_mode=2[/IMG] [img]https://photos-6.dropbox.com/t/2/AABv4xZMm44VWqXklTLLTELJ2T-nveiEUsVsC0nyR2OlWw/12/65410658/jpeg/32x32/1/_/1/2/IMG_20150715_144838.jpg/ENf04jIY5iIgASgB/lmwFUa2azeS-uzsdbBACBFlptdpBBxzPZQeNZ-R7tN0?size=1600x1200&size_mode=2[/img] I completely forgot that Drain -> Source capacitance was a thing and the 1k resistor paired with the ~500pf was taking a significant portion of the switching cycle to discharge. Threw a 22 ohm resistor in there instead and it worked flawlessly. [img]https://photos-3.dropbox.com/t/2/AAC1puZ92wU0GQAls474bZ5gQAHWE7CaIs8LMUrqNVY7Ow/12/65410658/jpeg/32x32/1/_/1/2/IMG_20150715_145103.jpg/ENf04jIY5iIgASgB/j5dfaHTaZCFEJYPHG5v5JleVqUUOPtE7iSLQMDTZCDc?size=1600x1200&size_mode=2[/img] Fuckin parasitics[/QUOTE] Seems your hotlinked dropbox images aren't working, probably check permissions. How fast were you running that mosfet? And for what purpose?

I didn't know they made milspec microUSB connectors. Damn, now I want some. Apparently there's similar ones that aren't milspec, need to do some digging.

[QUOTE=cartman300;48213678][thumb]http://i.imgur.com/0i4IIfX.jpg[/thumb] My dad gave me his IC collection! I can't even find the datasheets for half of them. :v:[/QUOTE] That's a Z80 right? Should totally build something using it. Pretty great collection though.

[QUOTE=ben1066;48214727]That's a Z80 right? Should totally build something using it. Pretty great collection though.[/QUOTE] I've also got a shit ton of quad NAND, quad NOR and quad AND gates. I could totally build a processor from scratch with this. If only i wasn't lazy, i didn't even complete my logic gate processor in that simulation software i have, it's only got 3 instructions.

[QUOTE=nikomo;48214604]I didn't know they made milspec microUSB connectors. Damn, now I want some. Apparently there's similar ones that aren't milspec, need to do some digging.[/QUOTE] You can get some pretty cool MIL connectors: MIL-Ethernet / MIL-USB: [img]https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcSyRGBp0vj-6oB_bxt5kmD_51Q2XZtV1Yy5HeP8BPbbJtiwKfcCAQ[/img]

[QUOTE=LoneWolf_Recon;48214361]Seems your hotlinked dropbox images aren't working, probably check permissions. How fast were you running that mosfet? And for what purpose?[/QUOTE] Rehosted to imgur. Right there it is running at ~50 kHz but it seems capable of driving it up to 250 kHz. I think it could go even higher with a better driving source. The lower end is limited by the transformer inductance. This is just a simple test circuit for driving a high side MOSFET but the aim is to build a discrete Buck Converter and Voltage Inverter. Also the reason I'm not using an IC bootstrap driver is the lack of many PDIP drivers and the cost for a single shitty one is ~$3.00.

Hey, seems like best place to ask on fp. Is there some kind of sensor I can get that would attach to wrist and go into USB port on PC and record my heartrate?

[QUOTE=arleitiss;48217107]Hey, seems like best place to ask on fp. Is there some kind of sensor I can get that would attach to wrist and go into USB port on PC and record my heartrate?[/QUOTE] Look up any USB ECG sensor, probably the ones that clamp to your fingers. Either that or you could build one yourself with some [URL="https://www.sparkfun.com/products/8661"]DIY[/URL] [URL="http://www.instructables.com/id/DIY-EEG-and-ECG-Circuit/?ALLSTEPS"]kits.[/URL]

[QUOTE=LoneWolf_Recon;48217852]Look up any USB ECG sensor, probably the ones that clamp to your fingers. Either that or you could build one yourself with some [URL="https://www.sparkfun.com/products/8661"]DIY[/URL] [URL="http://www.instructables.com/id/DIY-EEG-and-ECG-Circuit/?ALLSTEPS"]kits.[/URL][/QUOTE] Can the ones that attach to fingers be used on thumb?

No, for the same reason you can't take your heartbeat with your thumb, it has its own pulse. There are also IR sensors that will do the trick (the latest Samsung models have them, no idea how they work).

[QUOTE=Cakebatyr;48218796]No, for the same reason you can't take your heartbeat with your thumb, it has its own pulse. There are also IR sensors that will do the trick (the latest Samsung models have them, no idea how they work).[/QUOTE] It should actually work fine on the thumb... It's not like your thumb is on a totally different blood supply, it just isn't used for taking someone else's pulse because feeling your own could interfere with your counting.

Yeah, humans don't have separate hearts for our thumbs. I admit, that would be cool, but we don't. [editline]16th July 2015[/editline] I got myself a new toy. [t]https://i.imgur.com/mXoyURL.jpg[/t]

Hey, I ordered one too! Let me know how it goes in terms of setup time and dev environment.

Downloading IDE took forever, running the example code took a few minutes. The IDE is about as understandable as the Kryptos sculpture outside CIA's office in Langley.

So for the last couple of months, I've been working on a quadcopter. Since I don't have a fancy 6 channels remote control, and I don't have a big bag of money laying around, I'm using an arduino for the transmitter, and an arduino for the flight controller. As of today I've finally been able to start flight testing. It took several months to get all the parts ( ordered from China, find out you need something else, order from China and wait weeks again... ), do the programming and building, but now I'm finally able to start testing. Here's a video of today's best flight (Excuse the vertical video and overly enthusiastic remark at the end, my mom actually recorded it :v:): [vid]http://webm.host/04a6a/vid.webm[/vid] I'm still trying to get the best PID values so it's far from perfect, and the only control I currently have is a potentiometer to change the amount of thrust, so it's flying without basic controls, really. In order to get all of this working, I'm writing [url=https://github.com/Wolf-Code/Quadcopter]my own code[/url] for it and if anyone has some feedback, I would greatly appreciate it. The flight controller was designed in Eagle and ordered at dirtypcbs.com, and I'm currently waiting for the transmitter pcbs, which I've also designed in Eagle and ordered at dirtypcbs. Other than that, I'm using the MPU-6050 for the gyroscope and the NRF24L01 for the radio.

[QUOTE=xThaWolfx;48221132]So for the last couple of months, I've been working on a quadcopter. Since I don't have a fancy 6 channels remote control, and I don't have a big bag of money laying around, I'm using an arduino for the transmitter, and an arduino for the flight controller. As of today I've finally been able to start flight testing. It took several months to get all the parts ( ordered from China, find out you need something else, order from China and wait weeks again... ), do the programming and building, but now I'm finally able to start testing. Here's a video of today's best flight (Excuse the vertical video and overly enthusiastic remark at the end, my mom actually recorded it :v:): -vid- I'm still trying to get the best PID values so it's far from perfect, and the only control I currently have is a potentiometer to change the amount of thrust, so it's flying without basic controls, really. In order to get all of this working, I'm writing [url=https://github.com/Wolf-Code/Quadcopter]my own code[/url] for it and if anyone has some feedback, I would greatly appreciate it. The flight controller was designed in Eagle and ordered at dirtypcbs.com, and I'm currently waiting for the transmitter pcbs, which I've also designed in Eagle and ordered at dirtypcbs. Other than that, I'm using the MPU-6050 for the gyroscope and the NRF24L01 for the radio.[/QUOTE] Wow, you are using exactly the same hardware as i am. My arduino, the transcievers and gyro recently arrived. I have to wait for other atmega328 CPUs, some motors and rotors before i can assemble it though. Frame is homemade from some light wood. [editline]16th July 2015[/editline] Talking about that, what motors and rotors are you using? I still didn't order these.

[QUOTE=cartman300;48221841]Wow, you are using exactly the same hardware as i am. My arduino, the transcievers and gyro recently arrived. I have to wait for other atmega328 CPUs, some motors and rotors before i can assemble it though. Frame is homemade from some light wood. [editline]16th July 2015[/editline] Talking about that, what motors and rotors are you using? I still didn't order these.[/QUOTE] I'm using the cheap A2212 1000kv motors, with 10" long props, with a pitch of 4.5". Basically the most generic combo sold together on AliExpress, where I got all of my components :v:

[QUOTE=nikomo;48220857]Downloading IDE took forever, running the example code took a few minutes. The IDE is about as understandable as the Kryptos sculpture outside CIA's office in Langley.[/QUOTE] Isn't there an IDE for the launchpads that works similar to the arduino ide? I remember ages ago I used it with my MSP430s.

[QUOTE=xThaWolfx;48221985]I'm using the cheap A2212 1000kv motors, with 10" long props, with a pitch of 4.5". Basically the most generic combo sold together on AliExpress, where I got all of my components :v:[/QUOTE] How much has that cost you so far? Building one sounds fun but price scares me away.

[QUOTE=ben1066;48222797]How much has that cost you so far? Building one sounds fun but price scares me away.[/QUOTE] It's not cheap, but from the top of my head: 4 motors + 2 propellers per motor (clockwise and counter-clockwise) + bullet propeller adapter per motor + 30A ESC per motor = €50. Frame = €18. 1 2200 mAH 40C battery = €17 and one charger for said battery = €19. Then there's multiple electronics, such as the NRF24L01 modules (buy at least one high-powered one with an antenna, you won't have any practical range with two low-power modules), arduino pro mini's, joysticks, MPU6050, ordering the PCB's (I could've done it on perf-board, but I wanted to learn Eagle and it's neater, but you can save a lot of money by doing it on perf-board), etc. That last part is basically where you can potentially save quite a bit of money by simply buying a flight controller for several tens of euro's and just have that part done. You can then still make your own transmitter and put an extra arduino + NRF24L01 on top of the quadcopter to translate the transmitter's values into values the flight controller understands or, if you DO have a 6 channels remote control already, save the money of a transmitter as well. Although I've spent much, much more than I'd planned, it's been, and still is, a wonderful experience of joy and frustration in which I've already learnt so much. But really, you can make it as expensive or cheap as you want, although you'll probably spend around €100 at least if you try to do it my way and build everything yourself. If you already have certain things, like a battery or transmitter, your cost goes down substantially. OH and everyone thinking about doing this, don't buy a frame without checking the maximum propeller size.. Trying to fit 10" propellers where only 6" will fit is NOT going to work and sadly I know this from experience :v:

[QUOTE=papkee;48222361]Isn't there an IDE for the launchpads that works similar to the arduino ide? I remember ages ago I used it with my MSP430s.[/QUOTE] Yes, Energia. Haven't tried it yet.

[QUOTE=xThaWolfx;48221985]I'm using the cheap A2212 1000kv motors, with 10" long props, with a pitch of 4.5". Basically the most generic combo sold together on AliExpress, where I got all of my components :v:[/QUOTE] How much voltage are you giving those motors, and how much power do they eat up?

How not to wire a shower: [img]http://i.imgur.com/ROXTq8a.png[/img]

Anybody have experience programming menu GUIs? I can make the graphics part, and I know what things I want to be displayed, but I've been trying to figure out how to program in the physical navigation of the menu system. For instance, how I would navigate up and down through a list and enter into submenus, etc. Are there any useful libraries that could aid in this?