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Topic: Pitolino - a small data logging gadget (Read 12574 times) previous topic - next topic

pito

#15
Aug 03, 2012, 05:12 pm Last Edit: Aug 03, 2012, 06:42 pm by pito Reason: 1
@jraskell: - 164, 324, 644, 1284..
@BlueJakester: the pitolino template shield - that is a template only - so one can take the template (with header's ready pin layout, pcb size, hole positions) and draw his own board in the free Eagle CAD - ie. with sensors, signal conditioning (opamps), ADC, DAC, memories, additional sdcards sockets, or a CPLD or an FPGA, etc. etc. :)  As an example there is a protoshield with 0.1" grid for DIL packages and through hole components. You can design your own proto shield with smt pads when required..
This project is for people who want to learn more than programming only..

BlueJakester


CrossRoads

itead will do the full 50mmx 50mm pito. You don't need to artificially limit yourself to 49 x 49.
How about a schematic - I don't see a lot of the typical Rs & Cs on the layout, maybe they are just on the other side.

What does this mean:
1500mil header's spacing fits the breadboards.

breadboards are not 0.1" spacing like perfboard?
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

pito

#18
Aug 03, 2012, 05:37 pm Last Edit: Aug 03, 2012, 09:26 pm by pito Reason: 1
As an example - shield with 2 CPLDs, an accelerometer, an athm. pressure sensor, oscillator and a memory chip..
And some LEDs and signal connectors placed outside the stackable headers, so you can see them when more modules sandwitched..
:)

pito

#19
Aug 03, 2012, 05:40 pm Last Edit: Aug 03, 2012, 06:11 pm by pito Reason: 1
@crossroads - 1500mils means the distance (span) between the two headers rows, which are 0.1" pitch  :)
- there are parts on the bottom - I will add the picture to the first post (I deleted it)..
- both sides have got GND planes, for better grounding there are GND vias
- 49x49mm vs 50x50mm - I've seen a discussion on Itead's forum on that topic - where they measure the 50x50 - in the middle of the dimension line, or on its outer side??..

What about the Questions for final routing ? (see the first topic). Any recommendation ?
p.

fat16lib

#20
Aug 03, 2012, 08:00 pm Last Edit: Aug 03, 2012, 08:06 pm by fat16lib Reason: 1
One of my favorite small loggers is a teensy with a microSD that Paul Stoffregen sent me.  I use it with a sparkfun RTC next to the SD.

It is 18x30 mm http://www.pjrc.com/store/sd_adaptor.html.  It's about 12 mm tall with the two board levels.  

The microSD has a card detect switch.  I know you like the CS card detect but that never works well in practice.  In addition to problems I have already mentioned, here is another one.  With a one meg pull-down on a small unit like this you will touch something and noise will cause a false card detect.  Noise is a problem because the logger is connected to something else so it's not just a tiny board.

It would be nice if SparkFun made a piggyback board with microSD and RTC for their Pro Mini which is 18x33 mm.

pito

#21
Aug 03, 2012, 08:27 pm Last Edit: Aug 03, 2012, 08:55 pm by pito Reason: 1
@fat16lib - the sdcard's VCC switch and 1meg pull-down card detection are optional, you simply may not deploy the stuff on the pcb and use ie CS pullup instead. This board is a little bit bigger than yours, but people interested may design quite a complex shields for it.. A kind of a new standard :)
PS: I added a Q: where to connect the uSDcard card detection switch..

pito

#22
Aug 03, 2012, 08:34 pm Last Edit: Aug 03, 2012, 08:58 pm by pito Reason: 1
This is how a 3.3mm hole looks like. Not sure if the screw's head fits in..

CrossRoads

"where they measure the 50x50 - in the middle of the dimension line, or on its outer side??.."
Use a really thin line, the board will be cut to that.

I'll post this & then go back & look at the other questions.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

CrossRoads

Quote

1. Q: Which pin numbering scheme to use?? (avr-developers or maniac-bug, etc.)
2. Q: Where to connect the LED? Currently connected to PB0 (D0)
3. Q: Where to connect the SD_VCC switch? Currently connected to PC2 (D18)
4. Q: Where to connect the RTC's Alarm? Currently connected to INT0-PD2 (D10)
5. Q: Where to connect the SDcard's CS? Currently connected to SS-PB4 (D4)
6. Q: Where to connect the SDcard's socket card detect switch?

1. I of course prefer Bobuino, keeps Serial on D0/D1, SPI on D11-12-13.
2. I prefer the LED on D13, in keeping with original.
3. I would put this on a pin above D19 if routing allows. Allows for regular shields to be wired in to standard pins if desired.
4. I would put this on a pin above D19 if routing allows. Access it with pin change interrupt. Do not put it on the INTs for the serial ports. INT2 (PB2) if you want it on a hardware interrupt.
5.  SD card SS connected to SPI normal SS is fine. Other devices can use other pins.
6. I would put this on a pin above D19 if routing allows. Generally just a polled input? Or can be a PCINT.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

fat16lib

pito,

If you get to 50x50 mm, it's huge compared to loggers some of the users of SdFat have built.

50x50 mm is 25 sq cm.  A teensy at 18x30 mm is 5.4 sq cm. 

Using two boards makes it only 12 mm tall so it can fit in things like tiny airplanes as a "black box". 

Such a flight recorder is one of the smallest loggers I have seen.  It was custom built with an accelerometer.  It was about the same size as a Pro Mini or Teensy.

fat16lib

Since you have lots of space, how about an option for a GPS instead of a RTC.  Lots of mobile logging applications need altitude, location, time, speed, and track.

I like this part http://www.adafruit.com/products/790.  It's only 16x16x6.5 mm.  It has an internal RTC that runs on low power when the GPS is not tracking.

pito

#27
Aug 03, 2012, 11:59 pm Last Edit: Aug 04, 2012, 01:15 am by pito Reason: 1
@fat16lib - I have to rename the topic - as .. a (not only) small data logging gadget .. :) There is LPC1202 (package 2.17x2.3mm, 16pins) - my favorite for the next data logger :)
GPS - a good idea for the first shield..
@crossroads: thanks!
1. Bobuino - what is the idea behind that numbering pls? Compatability with UNOs pin layout, or?
(I am running my atmega32 and 1284p as per avr-developers pin numbering, no issues so far..) Most probably we will not connect an ..duino shield to pitolino, it does not fit :)
2. ?
3. Q: Where to connect the SD_VCC switch?  PC5 (through a "jumper resistor", active low)
4. Q: Where to connect the RTC's Alarm? PC7 (through a "jumper resistor", pullup 100k, active falling edge, oc)
5. Q: Where to connect the SDcard's CS? PB4 (SS direct)
6. Q: Where to connect the SDcard's socket card detect switch? PC6 (through a "jumper resistor", pullup 100k, active low, debouncing cap 10n?)



fat16lib

Since SS must be an output pin for SPI to work correctly use SS as chip select for an SPI device.  In this case using SS as SD chip select is a logical choice.

CrossRoads

1. As I said, I was trying to maintain shield compatibility.
D0/D1 for Serial, D10-11-12-13 for SPI,
I usually have on board jumpers so I2C can be connected to A4/A5, but also bring them out separate if A0/A7 are to be used.
Flipped A0-A7 around so that A0-A5 can be brought straight out to edge connector with A0 towards the power connector, and extra A6/A7 out past the regular analog header.
Original Bobuino, under -0022, the one with all the SMD parts, had PA0 to A0, PA1 to A1, big routing mess to cross all the pins end for end to match shield. When maniacbug did the later Bobuino, the Duemilanove style that is mostly thru hole, under 1.0, he flipped those end for end for me so the pins could go straigth out to the header, which you posted above. That's the one found in his github 1284 files now, which I use for my designs.
2. L LED on D13/SCK pin.
3-4-5-6. Look good to me.

If I'd been a little more knowledgable, I might have matched up the PWM pins to ensure D3,5,6,9,10,11 were all PWM, but I missed that.
It never came up during forum discussions as the original Bobuino developed.
(search "1284 eval", it's usually found as the first search term. That's the one you fixed up the uSD socket for me).

In the end, maybe it doesn't matter, you write your code for the hardware you have, and tweak your bootloader to flash the L LED on whatever pin you end up using if you want.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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