uC - Programming

[spirilis]

Nice!!! Good work. I've heard those things are a bitch to solder... I got my freebie kit from the 43oh guy, haven't unpacked it though.
PS a few weeks ago I bought one of the TI MSP430 professional programmers, the MSP-FET430UIF, and I noticed the box says "Made in Germany" on the label. Refreshing not seeing something "Made in China" for once!

 

[entropie]

Catching neonred on camera is impossible

 

[spirilis]

Well for what it's worth, with nothing specific on the horizon for projects (a few vague ones in mind but no rush on them), I'm diving *deep* into the Renesas RX. Was trying to choose between the ARM TI Stellaris I have or the Renesas RX and Renesas it is (bigger/badder dev board, more rare here in the USA, sounds like a worthwhile waste of my time; there are plenty of other folks figuring out the Stellaris right now)

Project #1: Create a TI LaunchPad adapter board for the RDKRX62N board so I can plug my BoosterPacks into it and write software for existing boosterpack-based pluggable hardware. I'm not a big fan of the Arduino layout, preferring to spend my efforts on using the TI LaunchPad boosterpack standard instead.
Eventually I'd like to produce my own LaunchPad (80-pin version most likely) using the newer RX63x series and a SEGGER J-Link debug header, unless the new 120+MHz RX600 series chips come out by the time I get to them. Not holding my breath though.

 

[entropie]

Cool that board would prolly be the right one for my current project:



This is robby, equipped with a raspberry pi (ARM dev board), wlan and a small LCD on wheels. I am still waiting for an order from China for the Alamode board, which is a shield on the GPIO boards of the rasp and which has the Arduino standardization (plus an RTC clock). With that I can use an adafruit motor shield to make it drive around.

I am planning to build a little helper, which reacts to speech commands. I have bought super sonic sensors as well, so it can navigate a bit and I am planning on odometrics and cartography as well. Maybe you can ask him later how much milk is left or what the current soccer games score is and he can connect to the internet and be a living wikipedia. All just ideas, gonna see.

Nice thing is that the LCD, which normally goes at 12 V works at 5 V as well. So I have written a script to physically switch of the signal ports of the rasp, to save power on the LCD, cause with no signal it shuts automatically off ( written in very bad C tho, cause I am no programmer: https://github.com/enthalpie/raspb_lcd_powersaver).

I have hooked all the stuff up to an Iphone emergency battery with 60 Wh, runs about 11 hours with LCD off

 

[spirilis]

Nice, sounds like a fun project for the rpi!

I heard there's a new BeagleBone coming out soon that's trying to compete with the RPi... supposed to be cheaper and more powerful (with HDMI finally, though no composite video out). From what I've seen those are a bit more capable/tons more I/O for the hackers. Supposedly adding onboard flash so the O/S isn't tied to the SD card (i.e. SD card can be an online-replaceable data dump). Haven't bought any of those ARM boards yet but I'll be looking at that new BeagleBone when it's out.

 

[entropie]

It's definitly a lot of fun, those bare boards close to the real tech, motivate you to do everything yourself. I found instructions on the internet to even build your very own Linux from scratch. I already compiled an OS for the arm architecture and it took my dual 3 Ghz machine about 8 hours, kinda funny; feels like StarTrek when the actors said: "it will take the computer about 10 hours to calculate the result".

I am watching the beaglebone as well, so far beagle or the omap board have been to expensive in relation to the RPi, but gonna see what comes next. With more expansion boards, I am going to wire my whole house

 

[entropie]

Fun with EagleUp (the model aint perfect, cause I lack the patience for drawing )

 

[spirilis]

Nice! I always wondered if anyone uses the 3D preview feature in those PCB CAD progs.
I always make my own footprints so I doubt I'd have much use with those. I also use DipTrace fwiw but I think it has that 3D stuff too.

 

[spirilis]

In other news, I have the shits for soldering 0603 SMD components. Building out 9 boards for the 43oh.com store (would be 10, but I discovered a refdes mistake and had to desolder some resistors; accidentally lifted the pad on 1 of the boards so it's now my scrap board) and each board has 31 SMD 0603-size components (plus a couple 1206's and then ICs + headers). It's a custom LaunchPad for the MSP430F5172 chip. Kinda nicer than the ones that come with TI's launchpad, closer to the atmel atmega328 in specs but has more features.

I definitely need to get a reflow soldering setup going...

 

[entropie]

Check this one out, I nearly already bought it:
http://www.beta-estore.com/rkus/order_product_details.html?p=13

Everytime I tried soldering 0603 manually I end up wanting to break things

 

[spirilis]

Lol yeah... I may have a solder reflow controller (or the hardware for one, anyhow) in a month or 2, got an order for a PCB from someone on the 43oh site (they found a glitch in their design though, so it'll be a bit longer). I definitely will need the stencil setup though... I don't have a laser etcher but I understand there are services available that do it, guess it's a question of how much money I care to invest in it. I'd read about a home-etching solution using aluminum soda cans and muriatic acid recently though. Probably something I'd be willing to try

 

[entropie]

Haha, better not turn entp just for stencils thats not worth it .

You may want to ask LadyAda: http://www.ladyada.net/library/laser/pcbstencils.html

There's a link at the top of the page, where a private person is referenced, who can do the stenciling for not too much money. If its worth it, basically depends on the quantity of boards you need later on. If you just want to do one board, I'ld take a very small brush and put the solder paste on the pads manually

 

[spirilis]

Lol at this point I am entering territory where angels fear to tread, with the Renesas RX. I got my RX62N demo board working with MacOS X using the USB bootloader option (so, not the SEGGER J-Link debugger, which doesn't seem to have any support on non-Linux or Windows platforms). I also got two of their promo boards for the RX210 (lower-end version, max 50MHz, think somewhere in a cross between Cortex-M4F and Cortex-M0+ competitor). One was free, the other was $25. I've developed "TI LaunchPad" adapter boards for both that are on their way, so I can use my existing boosterpack stuff with them.

What has become abundantly clear to me though is that most everyone who uses them uses the e2studio and/or HEW proprietary IDEs that Renesas provides. GCC is there (and KPIT Cummins' GNURX distribution integrates with the aforementioned IDEs, although it includes some proprietary software that they don't distribute with their downloads) but rarely do I see people using it directly. RedHat Global Services wrote the GCC port though, along with the Newlib port, and as such it does have an appropriate linker script + crt0.S to support bootstrapping a C or C++ program on the RX with the native GCC-only toolchain. I've since dived into linker scripts and adapted the default to my own (as the default linker script is written for a chip with 768K flash, the YRDKRX62N board comes with 512K), plus am thinking of developing one for the RX210 so I can give the toolchain a more "pure GCC" type of feel. One thing my RX210 launchpad adapter board does is break out the serial bootloader pins so I can create a special boosterpack for the lower half of that board which breaks out an FTDI chip, which one RedHat developer's RX tools supports. (There seems to be one guy on the RenesasRulz forums who works for RedHat, actually WROTE the GCC port, and tinkers with the japanese chips in his spare time. If it weren't for his work I would never have considered this platform workable at all!) That way I'll be able to compile & upload to this chip with fully open-source tools. Just no debugging unfortunately (although, as I've recently found, one hobbyist developed his own GDB "stubs" that compile into the app and communicate over one of the RX's many serial ports back to the host, which is just totally cool IMO).

So why am I going through all this effort for a company that obviously doesn't take the open source community all that seriously? I dunno, just call it "rooting for the underdog" syndrome.
But I do seem to have a couple fans on the MSP430 hobbyist forum who also own these Renesas kits and haven't found a goddamned thing to do with them... so I'll probably be selling some of my LaunchPad adapter kits (they're the kind of folks who care about the LaunchPad platform anyhow).

 

[entropie]

@spirilis

I had an idea that does make me a bit ... how to express it the best eloquently ... horny !

I have been wanting to build a CNC machine since I dont know when. I finished with the power electronics already for about a year but I am lacking time and mostly money to start buying the mechanics (The schematics for it I have finished). So now I have found a thing, you prolly already know about cause it's from the states that could solve some problems for me and create some new projects:

This's the printrbot jr:

It's a RepRap clone working with quite simple electronics (AVR+Allegro drivers+a mosfest for the extruder head). Even has a SD card to upload the GCode and switch of your PC while the machine is working.
It's a pretty archaic build mechanically, one that would get you fired from any job at my place in engineering but since its tension uncritical you can do it that way. And with the aim to create a cheap machine this thing is ingenious.

Now I can use the machine to make a lot of plastic boxes I desperatly need a long time for my electronics projects. But besides that I had another idea: you can make negative layouts for smd boards with it. Since you only need the layout or pattern for the application of the soldering paste, the plastic totally suffices. So you can basically get yourself an smd board, then make the negative plastic pattern and put the solder paste on and then place the components with your tweezers, put it in your reflow oven and your done.

Quite an easy way for mass production of stuff at home

 

[spirilis]

Heck yeah, 3D printers are cool technology IMO. And only getting better...
Not sure they'd be practical (precise & accurate enough) for doing SMD stencil type of work, but for making custom enclosures I think they sound wonderful.
I've heard there are businesses that'll run your design through laser-cutting or 3D printing so you can get a "taste" of it on demand. One of these days I'll have to give it a try...

 

[entropie]

I am gonna see what it can do, waiting for the delivery from the States atm; could take a while with customs :/. What I have seen about precision so far it could suffice for the biggest SMDs. Gonna see later, the construction definitly looks adventurous

 

[spirilis]

Ah nice, so you are building one up then? Very exciting

I built this out today, a rather whimsical trinket for my desk at work (showcasing it on my workbench in the basement @ home)-

It's a 1-gallon bottle of water with the label removed and a string of WS2811 individually-addressable bright RGB LEDs wrapped around the bottom. A rather overspec'd microcontroller attaches to it, providing the 5V power and its 1-wire data input (TI MSP430F5172 used since it can do native 5V I/O on some of its pins). The MCU board has one of those cheap Nordic semiconductor nRF24L01+ transceivers on it, and a basic TX circuit with another MSP430+nRF24L01+ is attached to my Mac. I implemented a form of DMX512 protocol over Nordic nRF24L01+ for this project so the water bottle lamp listens on channels 1-3 for the R, G and B values (sets all 28 LEDs to the same one, so the "individually addressable" aspect doesn't offer much benefit here), and just need to implement a little CLI-based serial I/O for the base station so I can pop into a serial terminal for an MSP430 + nRF24L01+ on my desk at work and change the color of that lamp. Might invest in a BeagleBone when the new one comes out and have a permanent Linux server on my desk for controlling those things. It's pretty bright but not a replacement for a lamp... there are 28 LEDs in there, at full 0xFFFFFF they each draw 50mA at 5V so that's 1.4A, times 5V it's 7.0W, not really that powerful for an LED lamp. Subtract a lot when you have it doing different colors since some of the individual R/G/B LEDs on-die will be duty-cycled lower. Two of those strips would be nicer IMO. Might look into it but I'd need a beefier 5V supply than a tablet charger (2.1A, think iPad).

 

[spirilis]

Heh, one side benefit I thought about here with using a big bottle of water--cooling is less of an issue, with water's high Specific Heat Capacity it can absorb a lot of heat and dissipate it efficiently if the bottle has enough surface area (this does IMO)... so that plus the neat light dispersion effect of the water & bottle makes it a nice medium for a high-powered LED lamp IMO. Might have to scale this idea up and test it out soon. That'll take a month or 2 since the parts I'll need (reel of WS2811's) all come from China...

 

[spirilis]

woot! now I have a new "nrfdmx" command in my grill monitor base station firmware, and my linux server has a script running:

#!/bin/bash

hex=$(od -N3 -x /dev/urandom | head -1 | awk '{print $2 substr($3,3)}')
printf "nrfdmx DEADDEED01 00 ${hex} -q\r\n" >> /dev/ttyUSB0

running this every 2 seconds, it's like a new-age lava lamp or something.

 

[entropie]

Haha that lamp looks awesomly alien and your desk looks similiar to mine . I have stereo speakers hooked up to the PC as well, they are even bigger than the monitor (sound's very important ).

If you are intrestred: I have built recently a switched power-LED supply which can even be dimmed via PWM. Here are some pictures:




Those are four 1W warm white pLED's hooked up to a cooling body 20 times as big. The whole circutry draws about 4,5 Watts so roundabout 89% efficiency.

Those 1W pLEDs have 95 Lumen of Lightpower, they are pretty bright already (look a bit darker on the picture). If you want more you can hook up 3W or 4W pLEDs as well. [the 1W hurt the eye tho already so be careful ]



You can connect up to 8 LEDs in red (rot) or 5 LEDs of any other color (nicht rot). The table shows what voltage you need then, since its voltage-regulated.

Power supply would be via a bridge rectifier or similiar and an AC trafo. You could use any direct current supply tho as well.

If you use a transformator like I did, you can connect 4 LEDs and the Trafo needs to have 15 Volts. The 1W LEDs need about 350 mA and the trafo I used gives 331 mA which is enough for all four. 4 LEDs have 3,5V which is multiplied with 4 = 14 V (with 5 LEDs you'ld need 17,5 Volts so all 5 LEDs would be a bit darker than with 4). If you take 3W or 4W LED's you just need to adjust the trafo to a model that gives 750mA (3W pLED) or 1000mA (4W pLED) respectively @15V.
You need to watch that the trafo doesnt give more than 15 V, cause its no-load voltage would be 19,2 V then, which rectified is about 23 V and that would be the maximum rating of the TS19377.

If you dont use a PWM or TTL signal to dim the LEDs, you can use a 0 Ohms resistor for R6 to connect Pin 2 to Vcc and leave C4 out.

R2,R3,R4 and R5 would be:
1W pLED @350mA = 1,2 Ohms and 1,8 Ohms parallel (2 resitors)
3W pLED @750 mA = 1 Ohms and 3 x 1,5 Ohms parallel (4 resistors)
4W pLED @1000 mA = 4 x 1 Ohms (4 resitors)

R1 would be:
1W pLED @350mA = 220 Ohms
3W and 4W pLED = 470 Ohms

Most important thing: connect the LEDs in series, never parallel. If you connect them parallel, only the 1st LED in line will light at all but break after a short time.

If you want more info ask away. Here's the board layout: http://www.elektor.de/credit-payment.589.lynkx?event=Zur%20Kasse&productGuid=bb7368b7-89e7-43b4-b3ac-2f7480c9e15f

A bit nasty to solder that SMDs tho :/