uC on a strip?

prof_braino · 2013-07-11 09:29

Anybody try this for a prop?

http://www.instructables.com/id/YABBAS-Yet-Another-Bare-Bones-Arduino-on-Stripb/

If it were $2-$4 without the prop, I would certainly be interested in a "add you own".

I would wish the payout include an option for a FDTI chip, and a 5v regulator.

Would this be doable?

davejames · 2013-07-11 11:15

...welllllll - there's this:

http://www.parallax.com/Store/Microcontrollers/BASICStampModules/tabid/134/ProductID/907/List/1/Default.aspx?SortField=UnitCost,ProductName

A little more than $2 - $4, but it's all there!

prof_braino · 2013-07-11 11:53

Yes, its $20 too expensive and lacks pins 19-31, and the FDTI chip.

I was looking for a lowest cost strip board project, WITHOUT the prop chip. I would get the parts in bulk, and have the kids build them in class.

Bill Henning · 2013-07-11 11:55

no

Minimum Prop support parts:

3x 100nF ceramic caps
3x 33uF electrolytic caps
1x 32kx8 EEPROM
1x 5Mhz crystal
1x L1117-3.3v voltage regulator (assuming you will power from ~5V)
1x 4 pin male header (for PropPlug)
1x 40pin dip socket
1x 8pin dip socket
1x strip/proto board

You can check the qty.1 pricing for each part above at digikey.com, I think you will find it will come to significantly more than $4 before shipping

A PropPlug is about $15, an FTDI chip (that you'd have to surface mount, add connector, pcb etc) would cost more.

prof_braino wrote: »

Anybody try this for a prop?

http://www.instructables.com/id/YABBAS-Yet-Another-Bare-Bones-Arduino-on-Stripb/

If it were $2-$4 without the prop, I would certainly be interested in a "add you own".

I would wish the payout include an option for a FDTI chip, and a 5v regulator.

Would this be doable?

davejames · 2013-07-11 13:28

prof_braino wrote: »

Yes, its $20 too expensive and lacks pins 19-31, and the FDTI chip.

I was looking for a lowest cost strip board project, WITHOUT the prop chip. I would get the parts in bulk, and have the kids build them in class.

...errrrrr - sorry!

Phil Pilgrim (PhiPi) · 2013-07-11 14:31

The FT231X (~$2.00/C) provides a regulated 3.3V @ 50 mA and a 6 MHz clock output -- possibly obviating an external regulator and a crystal. 50 mA is not enough to power a Prop running 8 Spin cogs at 96 MHz (6 MHz/pll16x), but it might be enough at 48 MHz (6 MHz/pll8x). Even with such a minimalist approach, $4.00 still seems quite a stretch. You still have to add a PCB, passives, and connectors to have a working system.

-Phil

tonyp12 · 2013-07-11 16:54

SiLabs 2102 and 2110 provides 100mA output and also 6mhz.
2110 is a hid-usb and either need support implemented in prop-tool or someone writes a vcp for it.

Cluso99 · 2013-07-11 17:09

prof_braino: You will just have to wait a little longer till I get a batch of boards done

prof_braino · 2013-07-11 19:04

Bill Henning wrote: »

Minimum Prop support parts:

3x 100nF ceramic caps
3x 33uF electrolytic caps
1x 32kx8 EEPROM
1x 5Mhz crystal
1x L1117-3.3v voltage regulator (assuming you will power from ~5V)
1x 4 pin male header (for PropPlug)
1x 40pin dip socket
1x 8pin dip socket
1x strip/proto board

You can check the qty.1 pricing for each part above at digikey.com, I think you will find it will come to significantly more than $4 before shipping

A PropPlug is about $15, an FTDI chip (that you'd have to surface mount, add connector, pcb etc) would cost more.

So, I would replace the 32K eeprom with 64k eeprom;

3x 100nF ceramic caps
3x 33uF electrolytic caps
1x 64kx8 EEPROM
1x 5Mhz crystal
1x L1117-3.3v voltage regulator (assuming you will power from ~5V)
add a 5v regulator;
1x L1xxx-5v voltage regulator (to power from external battery etc)
And maybe a switch to ensure USB power and external battery are not connected at the same time.
1x 40pin dip socket
1x 8pin dip socket
1x strip/proto board

... and remove the propplug and use the FTDI chip directly. Instead of a mini USB, maybe we could hack the end off surplus USB cable and wire it directly.

While the one-off price would be higher than $4 (I'll check the exact numbers next), I'm thinking it could still be less than the $30 for a quickstart or $24 for a mini.

The bulk has been about half of the on-off price. Since its a kit, it could be doable.

Not that my eyes could do much for hand soldering on to surface mount parts, I'm just looking at the prices for now.

Thanks for the list!

Humanoido · 2013-07-11 20:12

The Propeller Simple Spin Board is more minimal than Bill Henning's good list. It should be easy for students to assemble in about 5 minutes. The concept is to load and run programs from the prop's RAM using a host. It could use another prop and EEPROM to load a specific program, or you could add a preprogrammed EEPROM.

Outside Source

Phil Pilgrim (PhiPi) · 2013-07-11 20:38

It doesn't get simpler than that!

Humanoido, in your photo, it looks like the Prop chip is shifted up one hole in the breadboard -- or maybe parallax (small-p) is playing tricks with the image. Also, never leave out the bypass caps!

-Phil

Humanoido · 2013-07-11 22:08

Phil Pilgrim (PhiPi) wrote: »

It doesn't get simpler than that! Humanoido, in your photo, it looks like the Prop chip is shifted up one hole in the breadboard -- or maybe parallax (small-p) is playing tricks with the image. Also, never leave out the bypass caps! -Phil

No tricks. Originally the circuit used a resistor with a small LED and needed the bottom hole to hold it. Substituting a larger LED would not need the resistor. The hole was left there for someone that may not have the larger LED. I have a prop chip running off and on for a couple years without the bypass capacitors. Pure luck? I have no idea. Most of this stuff is so far above me it seems like magic.

Phil Pilgrim (PhiPi) · 2013-07-12 00:01

Humanoido wrote:

have a prop chip running off and on for a couple years without the bypass capacitors. Pure luck?

That would be a yes.

-Phil

WBA Consulting · 2013-07-12 00:20

I have often thought of revamping my M44D40+ module to accommodate a surface mount EEPROM and crystal to reduce the height of the parts which allow an even better chance to provide the board built up without the QFN Propeller. The end user can supply their own DIP Prop and plug it in to the stacking headers.

It can be used with a DIP Propeller in its current state, just needs the taller style stacking headers.

Fernand · 2013-07-12 02:59

Can an Arduino style "FTDI Basic" be used to program and debug (w/ ViewPort?) a Propeller Mini, or is there some overrding reason to stick to the Prop Plug?

Some possible issues:

I see that Pin 1 on the Mini's J3 is labeled Rx, so that would be the pin that needs a resistor ?
But the Prop Plug is also labeled Rx on pin 1. So which is the Mini's input pin, 1 or 2?

Does the CTS pin on an FTDI need to be jumpered ? high or low?
Should the DTR pin of the FTDI go to the Mini's Reset?

Can you feed the Mini's 5v on J2-4 with 5v from the FTDI header without hurting the regulator?

Thanks!

p.s. Love that M44D40+ and the PowerTwig! Can an FTDI be used for those?

p.p.s These Chinese power supplies I ran into are handy in that they provide 5 and/or 3.3 v to the 2 rails of a breadboard and/or to a USB plug. They're supposed to be rated at 700 mA, but I find the regs seem to run awfully hot even drawing 350 mA from the 5v side. There's not much copper surface there ;-) Epoxy on some heatsinks? Gob-solder the tabs?

Cluso99 · 2013-07-12 05:03

Unless the pcb has the transistor reset circuitry which is driven by DTR (but can be RTS) you will need to build this in. My 1"sq CpuBlade has the transistor reset circuitry onboard as a linkable option. I am not sure if anyone else includes this circuitry. I did this so that other FTDI and cheaper equivalents can be used. If the USB chip is 5V then a series dropping resistor (~3K has been suggested) should be included in the P31 (serial in) line.

skylight · 2013-07-12 05:50

prof_braino wrote: »

Yes, its $20 too expensive and lacks pins 19-31, and the FDTI chip.

I was looking for a lowest cost strip board project, WITHOUT the prop chip. I would get the parts in bulk, and have the kids build them in class.

I'm wondering whether it was a design issue that stopped parallax from putting all the pins available?
The size of the mini is ideal for small projects just the lack of pins letting it down as an ideal project board., I'm hoping for a quickstart type board with all the pins and usb , eeprom etc minus the touchpads and leds that are not necessarily wanted on every project.

prof_braino · 2013-07-12 07:42

I'm considering the M40D44+power twig, quickstart, propmini, simple spin, and everything else I can find. These are all good options. But I don't want to run just the minimal test program, the intent is to find some thing to run the LittleRobot: 2 steppers [28BYJ + ULN2003], SR04, and HC05. It has to be cheaper than $14 per unit.

I know this is an impossible request, that's why I made it!

Cheating is allowed.

So maybe the cost of two or three battery holders would be an alternative to a power supply and regulators? 2 cells for 2.2 to 3 volts; 3 or 4 cells for 3.6 to 4.5 volts, and for cells for 4.8 to 6 volts. I'll look at this also.

Remember, I plan to take advantage of bulk purchase price, so the one-off cost is just the baseline cost.

I think the EEprom would be required, unless there is a way to unplug the terminal connection without causing a reset.

Is there a way to get the prop to talk directly to the PC USB connection (at 1.5M?)?

Fernand · 2013-07-12 08:27

So the only thing missing on the M44D40 is the USB. What prevents mounting an FTDI type chip and a micro USB jack underneath? Even if it had to lengthen the board a bit, but keep the full DIP40 pinout. I switched from the Arduino Minis that are a lot like the Prop Mini in that they are missing a few pins and lack USB, to the Nanos, that have it all, for the same price. Using an external USB plug is a nuisance, and the USB is a useful thing in the field for debug and as a bona fide I/O. The more I use 'em, the more I like 'em. Perfect format. The narrow shape leaves room on the sides of the breadboard. Snap a design into a 400 point breadboard faster than you can think ;-)

Martin_H · 2013-07-12 09:37

Fernand wrote: »

Can an Arduino style "FTDI Basic" be used to program and debug (w/ ViewPort?) a Propeller Mini, or is there some overrding reason to stick to the Prop Plug?

I work with both the Propeller and the Arduino, and use an FTDI breakout board that can be switched between 3.3 or 5 volts. It works fine with either microcontroller. I got it from Wulfden and for $18 Brian included a Propeller Multi-BUB which remaps the pins from the Arduino to Prop Plug standard. See http://www.wulfden.org/TheShoppe/pa/index.shtml#P1 and here's the same product at Modern Device: http://shop.moderndevice.com/products/usb-bub

Martin_H · 2013-07-12 09:40

prof_braino wrote: »

I'm considering the M40D44+power twig, quickstart, propmini, simple spin, and everything else I can find.

I have an M44D40+ and power twig combo and use it all the time. It's great for fast prototyping on a breadboard.

tonyp12 · 2013-07-12 16:15

How about this pcb, it straddles the DIP Prop on a breadboard.
USB/Charger powered and 1Amp 3.3v VReg
It got 5mhz crystal,eeprom and ftdi uart
BreadBoard_Prop.jpg?psid=1

prof_braino · 2013-07-12 16:43

It looks really good, except for missing most of the pins. Hey wait.... It straddles the chip that already on the breadboard? HEY THIS IS GREAT!

How much does it cost for one? How much for a bunch? 64K eeprom?

What would the difference be if it included an 5v regulator, so I could have a single battery pack? (not to be a choosy beggar and all)

jazzed · 2013-07-12 17:31

Cool board! Even cooler if it was upside-down.

tonyp12 wrote: »

How about this pcb, it straddles the DIP Prop on a breadboard.
USB/Charger powered and 1Amp 3.3v VReg
It got 5mhz crystal,eeprom and ftdi uart

Fernand · 2013-07-12 17:59

Great. But aren't an eeprom and crystal non-negotiable parts of a standalone system, that don't belong on a temporary programming/prototyping tether? Correct me if I'm missing something, but isn't this a bit like putting your liver in your hat?

I can see breadboarding temporary power and USB interface with such a boardlet, which you then replace with say a battery and you're off and running. But if you remove this board you leave behind a lifeless chip with no clock and no program, right? I can see its utility as a way to breathe life into a Prop chip, which might make sense for the low level classroom, but not for real world rapid prototyping, which is better served by a Prop equivalent of a Nano or Mini, i.e. more like the M44D40.

Somehow I can't imagine students wanting to build only tethered systems.

tonyp12 · 2013-07-12 18:45

You have to leave it on all the time, as making it without fdti will only save $2
And if starting to separate everything you end up making the breadboard cluttered again.

If you fry your Prop, easy to replace the dip.
You will power it with microusb-charger or microusb lipo universal Power Extender.

With DIP Prop + above board + small breadboard, the goal is the magic $19

Fernand · 2013-07-12 19:15

Anyway thanks, for a 5v FDTI to a Prop, it's pin 2 of the Prop Plug header that's the input to the Prop, and where a resistor is needed. And the various Prop-compatible FDTI adapters suggest that yes, DTR from the FDTI should go to the Prop's Reset, and I guess a resistor or maybe an RC network might be indicated.

tonyp12 · 2013-07-12 19:34

>DTR from the FDTI should go to the Prop's Reset,
The board is using a cheaper solution:
RTS# is inverted by a software setting and by just having a cap in series to Prop reset, it should reset (I have not tried this yet)

Ariba · 2013-07-12 20:36

Yes, inverted RTS or DTR with a series Cap works well, I do it since years.

Andy

Duane Degn · 2013-07-12 20:43

tonyp12 wrote: »

How about this pcb, it straddles the DIP Prop on a breadboard.

Wow. Another cool board Tony.

It's got me thinking.

Cluso99 · 2013-07-12 20:55

My CpuBlade has everything except the additional 5V reg and the FTDI chip (requires series resistor in P31 line if operated at 5V but it has the DTR transistor reset circuit onboard) in 1"x1". Other plugin boards are available. $15 is doable.

uC on a strip?

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