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Revisiting FEZ Ant


#1

In case you do not know what it is, look here please http://tinyclr.com/forum/12/4153/

Back to FEZ Ant. I see you guys didn’t make any prototypes although there was a lot of interest, why? Also, we now have “gadegeteer” so it is easy to make a small board with gadgeteer sockets then expand it anyway you like using modules? Wouldn’t this be easier than using FEZ Ant? Remember the the extender module as well.

What is important here?
Does it has to be small? Flat? (flat as in no gadgeteer-sockets).
Is on board power needed? If you had to choose between size vs on-board power?
If you can buy it now, how much should it cost?
What is your credit card number?!!! I am just kidding :slight_smile:

Can you please give me an example of how you will use it and how FEZ mini will not do the job?


#2

Two posts from you towards the end of that thread:

Which turned out to be about the your impending production line. So rather than getting a few made ourselves, we waited. The momentum we had fizzled. I got distracted by Gadgeteer stuff. My goals were/are cost related, keep it small and cheap. Mini is nice, but is also $40. I think we got this down into the $20-25 range. No sockets, no headers even. This was not meant to be a prototyping board. Disclaimer: this is only my opinion about why a batch of boards never got made via DorkbotPdx or other service. Feel free to correct any misinterpretations.


#3

I agree with Ransom. I’m looking for something cheaper that I can put into permanent projects. However, since the Ant was discussed I’ve become a Gadgeteer convert and lately I’ve been thinking how really cool it would be to basically be able to have a Gadgeteer board that is small and I can only solder on the sockets that I would need. Although it would be more expensive overall, I’m seeing the possibility that more and more “permanent” projects will be built using Gadgeteer modules. Perhaps they don’t really need a socket on the mainboard side. The cables could be soldered in place. It would be nice to have the option. An ideal solution (although not at all practical) would be a web page where you could go and say “I need a Hydra board with two A sockets, two U sockets, & two X sockets” and have a board only large enough for that created. I have two projects running on Panda-IIs right now that I very badly want to convert over to Gadgeteer but I can’t justify $70 each for mainboards. $25 each would probably have me buying a new one every month :wink: FEZ Mini won’t do it in this case because it’s not Gadgeteer compatible.


#4

For me, the priorities were #1 cost and #2 size. That means no onboard power, no sockets, nothing not absolutely necessary or specific to any type of project. The model here is the mini, but cheaper and without the things that aren’t generally useful (such as the built-in linear power supply).

As Ian noted, the goal here is permanent placement, not prototyping, so no prototyping-driven features are needed or desirable. The MCU itself, absolutely required hardware (crystals, decoupling caps), and .1" holes for I/O, to be populated with whatever header/wire/whatever is convenient for the particular project. Unlike Ian, Gadgeteer doesn’t interest me at all, primarily because of the associated cost. As I’ve said before, it’s the small/cheap/low-power end that interests me, and Gadgeteer (so far) doesn’t target that market.

I’d make a few boards right now, but you hinted at the big announcement, so I’m currently making plans for a redesign :slight_smile:

Here’s the key takeaway from the Ant thread (for me):


#5

Hi

Cheap and small are key points to transform a prototype into a permanent device.
If it is not cheaper than a Panda, while not using a Panda…

It should be also as flat as possible. If we plug this into a main board, we should not reach the height of shield. So the total height of the board once mounted on a main PCB should be not much higher than a good’old DIP package. Let’s say 6 mm (sorry European-metric guy :wink: )

With regards to the power supply, I think that a 3V3 power supply for the USBizi chip is ok but we don’t need to power the whole solution from this. The main board will surely have its own power circuit with 66% @ 5V and 33% @ 3V3 and should be able to be powered from batteries. So I would not like to find a dual-stage power circuit like on the Panda (VIN -> 5V -> 3V3). Just a single stage VIN (9…4V - at least should support 7.2V or LiPo batteries) to 3V3 with minimum mA to power the USBizi + a little more parts (+50%). It should be bypassable so if the main board is 90% 3V3, it will power the USBizi directly…

For me it some kind of big-pins drop-in replacement for the USBizi chip for people whose fingers and eyes do not allow to play anymore with TSSOP packages ;D (I’m entering this category :frowning: )
So it should less than twice the price of the bare chip. So 20-22$ is a maximum.

I think that one of the success of the Arduino is the availability of the DIP package version of the processor which makes easy to create low cost PCB, even wire-wrapping.

cheers


#6

It’s exactly because there are so many different power supply situations that I don’t think any should be included on the board. Certainly, in a battery-powered situation, you wouldn’t want a terribly-inefficient linear regulator (also known as space heater) to be giving you 3.3v from your 7.4v LiPo.

Built-in power supplies are GREAT for prototyping. For more permanent installations, however, you nearly ALWAYS want a switching setup, not a linear one, and that’s outside the scope of the module itself.

I think of the Ant as the “USBizi module”, the “EMX-lite”, the “USBizi in a DIP package”, or the “USBizi without SMT soldering”.


#7

I was after what can only be described as a DIP package USBizi. I want to create small run commercial products for field tests - before committing to a permanent board layout using the flat pack.

A breakout board would work but it is very convenient to also have some of the must-have components like crystals on board already.

I also want to be able to remove the “brains” and put it on a different motherboard - because I rarely get the entire board 100% right in the first design. This is not my full time job so I can’t really spend hours and hours to get it perfect in the design phase. It would be a shame to scrap a UsbIzi because of a PCB mistake or change of plan once you actually start seeing how the board works in the enclosure or how your switches or sockets must be positioned.

A big irritation at the moment is the hacking going on to bring the USB port to the outside of the enclosure… Here an Ant on the board and a Usb socket where I want it would make a big difference.

Have a look at the attached pic of my RFID reader. A Mini doesn’t have enough pins. The Ant would be perfect to replace the Panda in this design.


#8

That was exactly my design goal. USBizi with the bare minumum components (crystals, decoupling caps). I also planned to put the pads onboard for the USB machinery, but one could choose whether to populate those pads based on need.


#9

Enough said :slight_smile: It is exactly what we have planned. I wanted to hear it from you guys to double check.


#10

Nice!


#11

Last question, headers or holes. There is no third option.


#12

+1 Holes…


#13

Holes


#14

+1 holes
Always easiest to solder headers if needed than removing them if unwanted


#15

I vote for header holes! See devhammer’s IR Emitter module.

http://www.tinyclr.com/forum/21/5554/#/7/msg53041


#16

@ ianlee74 - what does devhammer’s IR module have to do with a holes or headers decision?

Holes wins, even if everybody else says headers, which they won’t, of course…


#17

@ ransomhall

I think (Ian, correct me if I’m wrong) that he is referring to the fact that I plan to make the IR LED Array module available in multiple configurations…which would support the notion of holes, rather than headers, which limits the possible configurations. So I think you and Ian are voting for the same thing. :slight_smile:


#18

I’m voting for oversized headers/pads around the holes as devhammer did on his module. Normal pads are easier enough to solder a top mount wire too but why not make the pad a full rectangle rather than a small oval. The copper is free. :wink:


#19

in my book header does not equal pad… still confused but whateva…


#20

Don’t worry about it. I’m tired beyond belief…