$9.00 Arduino Board for the Pi

[Jim Manley]

A recent IndieGoGo project initiated by BorderlessElectronics.com (BE) sought to attract enough contributors to make it possible to have at least 1,000 Arduino Leonardo compatible boards fabricated by a Chinese manufacturer such that the cost of each board could be $9.00 in single-unit quantities, plus $3.00 for shipping directly from China. Last week, the project campaign was ended a week early after 7,015 contributors put up $164,343 to have 15,000 boards manufactured by the end of September, fifteen times the number originally needed for the project to go forward. The project manager actually had to cap the number of boards at 15,000 in order for the project to remain withing budget and schedule to complete delivery by the end of September.



It's known that a number of Pi enthusiasts ordered some of these boards because, well, at $9.60 - $12.00 delivered (depending on quantity), why not? The manufacturer reportedly has an established track record fabricating quality, tested Arduino products at quoted prices and delivering them within contracted schedules. The Leonardo is one of the most recent Arduino models that has a superset of features of the very popular Arduino Uno, using the surface-mount ATmega32u4 processor that includes a built-in USB interface that requires an additional integrated circuit on the Uno board, making it more expensive to build and slightly decreasing reliability. The Leonardo also has a few more analog inputs and pulse width modulation (PWM) digital input-outputs than the Uno.

As noted in the photo above, in addition to the Leonardo-compatible board, the BE project will also be delivering a 180-point solderless 0.1-inch mini-breadboard, six LEDs (2 red, 2 green, 2 yellow) with current-limiting resistors, a photoresistor with matching resistor, 10 1K ohm resistors, five signal diodes, two NPN signal transistors, a buzzer, three pushbuttons that fit onto the breadboard, 10 breadboard pin-jumper wires, a USB-A male to micro-USB male data/power cable, and a 9-volt battery to 2.1 mm male adapter cable.

Now that the BE campaign has ended, the manager will be busy through September monitoring manufacturing, testing, and shipping progress and approving manufacturing milestone expenditures. We plan for the Pi version to also include the experimenters kits that are coming with the BE board if the manufacturer will extend that offer. In the meantime, I have been in contact with him about building a Pi-specific version of the BE board. It would be the same board except that it would have a 13x2-pin female header with 0.1-inches between pins on the underside that would connect to the Pi's GPIO male 13x2-pin header. The GPIO interface pins would be directly connected to the appropriate Leonardo pins to establish a common ground, and with the Arduino transmit and receive pins connected to GPIO pins configured for UART serial port operation. This will allow direct programming of the Arduino by the Pi using either the command line or the Arduino.cc integrated development environment (IDE). Arduino digital I/O pins could be connected to specific GPIO I/O pins, although it is yet to be determined whether that would be via jumpers between 0.1-inch female headers.

It's intended that the Pi could be powered from the Arduino board via the 5-volt pin on the GPIO header if the Pi's printed-circuit board traces can handle the current and current-limiting protection can be provided. As peripherals plugged into the USB ports on the Pi can account for as much as an amp of current alone, it may be necessary to use a cable connected to the output of a 5-volt regulator on the Arduino board that is terminated on the other end of the cable with a male micro-USB connector that would plug into the Pi's female micro-USB connector.

The BE project has essentially acquired almost all of the ATmega32u4 devices available via distributors through at least mid-September, so that might delay being able to build a Pi-specific Leonardo board. In the meantime, I'm also considering building an Arduino Uno compatible board using an ATmega328 dual in-line package (DIP), but without the extra integrated circuit for the USB interface since the GPIO interface will be able to program the Arduino via a UART-configured GPIO port. This board would share the physical interface of the BE board (e.g., compatibility with Uno shields) and would also cost $9.00 in single-unit quantities, plus $3.00 for shipping. The same bulk discounts noted on the BE site would also apply if the manufacturer agrees to continue to offer them.

We plan for the Pi version to also include the experimenters kit that's coming with the BE board. Since the concept and price-point of the BE board have been proven to be extremely popular, we are considering a direct campaign that doesn't require going through IndieGoGo.com, Kickstarter.com, etc., and incurring upwards of a 10% cost increase. We plan to accept the same sources of payment that those crowd-funding sites do since the payment processors provide the protection for customers, not the crowd-funding sites. As soon as we have 1,000 boards ordered, we can start production and continue doing so as long as the pipeline remains filled with orders.

We would appreciate your feedback on the following:

1 - how many of the $9.00 (plus $3.00 shipping) Pi-specific Leonardo and/or Uno compatible boards would be of interest to you (number of each)

2 - should the Pi be able to be powered by a 5-volt regulator on the Arduino board

3 - should the Uno compatible board include a USB interface at an increased cost of about $2.00

4 - should direct funding or a more expensive crowd-funding site be used

5 - any other comments or questions

Looking forward to hearing from you!

[ShiftPlusOne]

1) I have supported the indiegogo campaign, so I should be set with arduinos for a whiole, but I would probably order a pi-specific leonardo or two. At least if more details are released (what's your track record? where are they being manufactured? where are the parts sourced from? what's the breakdown of costs?).
2 & 3) Either way is fine by me. I am not a fan of feature creep.
4) Indiegogo and kickstarter are established and easy to deal with, so I would prefer one of those.
5) Be careful if you're going to use paypal as a payment option for direct funding. They have messed up many projects by freezing funds. I don't know if their policy has changed, but large quantities of pre-orders may be lost.

[JoeDaStudd]

1. I'd buy a single Pi specific one (to start with).
2. Having the option there would be nice, but always on I'm not to sure about.
3. Personally it would be more then worth the cost as it would make the board multi-purpose and not RasPi dependant.
4. I've never used crowd funding sites, but at the same time I would be reluctant to give money to a company I'd never heard of.
5. Personally I never got into the Uno boards. I either want something with a load of connections like the mega, something small like the nano/pro or something custom. Would there be a super cheap Mega in the future?
Anyway love the idea of cheap development/tinkering boards and wish the current project, this project and future projects the best of luck.

[RaTTuS]

I would have 4
make sure it fits inside the RPI footprint if possible
so it will fit inside a case [with the top off ...

[Steven Boelens]

1) I would probably buy a few (2-5).
2) Nice to have but not essential if it inflates the costs.
3) For an extra 2 USD: Yes.
4) No opinion.
5) No.

Steven.

[Mortimer]

I supported the Leonardo project on Indiegogo, and I am looking forward to seeing the thing when it turns up.

(1) Initially I would only go for one Raspi-Leonardo.
(2) Nice to have but not essential.
(3) Yes, especially if it can operate as an OTG USB connection too.
(4) I think I would prefer something through crowded funding site. It offers more transparency and assurance to small investors.
(5) Nothing further to add.

[Ik0adr]

1) I would buy one
2) Only one power supply would be nice
3) To program the Arduino or for what? But at that price would be useful anyway..
4) Direct funding would be OK

Best regards,
--Federico

[Jim Manley]

what's your track record? where are they being manufactured? where are the parts sourced from? what's the breakdown of costs?

We'll be working with Harold at BorderlessElectronics.com and using his Chinese manufacturing partner. The IndieGoGo project comments have the contact info for the Chinese manufacturer, which checks out. They've done Arduino devices already and are the main reason that the experimenters kit is included. The BE IndieGoGo project homepage provides the breakdown for every cost, the BOM, and even detailed costs for each quantity offered, down to the penny for every item.

Be careful if you're going to use paypal as a payment option for direct funding. They have messed up many projects by freezing funds. I don't know if their policy has changed, but large quantities of pre-orders may be lost.

That usually happens to new accounts that start getting large numbers of orders all of a sudden and then there are complaints about a number of orders not being delivered, etc. We have an account that goes back to PayPal's first year in business that has had much larger amounts paid into it and any complaints were shown to be inaccurate via verification of deliveries, etc.

Plus, we won't be spending money until we get the minimum number of orders, so if anyone cancels any charges, we won't proceed until we have enough that's been approved over the minimum. The BE project reached their minimum in five days, and ended up with orders 15 times their original goal in three weeks. While I don't expect we'll reach those numbers, since they had to cap orders I think we'll reach the minimum within a week or two, especially once BE's manufacturer starts delivering working boards to lots of people.

[ShiftPlusOne]

Sounds good. In that case, I would definitely order at least 2 and wouldn't mind paying directly.

[panik]

1 - how many of the $9.00 (plus $3.00 shipping) Pi-specific Leonardo and/or Uno compatible boards would be of interest to you (number of each)
Cheap microcontroller breakoutboards are a good thing. Depending on the form factor (see 5) probably none.

2 - should the Pi be able to be powered by a 5-volt regulator on the Arduino board
Skip it, and draw power from the Pi. Also, run the Atmel on 3.3V. It makes interfacing the Pi easier (uart, i2c, spi).

3 - should the Uno compatible board include a USB interface at an increased cost of about $2.00
Skip it. Program either through uart with a bootloader, or spi without a bootloader. Since it's Pi-specific, it's all there. Gratis.

4 - should direct funding or a more expensive crowd-funding site be used
I wouldn't know, but good luck either way!

5 - any other comments or questions
Thanks for asking, here's a rant. You mention 'compatibility with Uno shields'. The pins on the 'standard' Arduino do not line up to a standard 0.1" protoboard grid, rendering it impossible for makers/hackers/tinkerers to easily create their own 'shields'. Which is exactly the purpose of an Arduino, right? I mean to rapidly prototype something, and then make a PCB if necessary (it is for me, anyway). After buying an Arduino and trying to create a shield with a piece of protoboard, that pissed me off to no end. It doesn't fit! It's making the shields a proprietary thing almost. If I didn't know better I'd believe 'they' did it on purpose, to make me buy their stupid overpriced shields.

More and more modern devices and microcontrollers run on 3.3V nowadays, and I believe most shields made for the Arduino expect 5V. I was hoping the shields with this form factor would soon die a quick death because of this, but it seems people are still hanging on to this horrible mistake. A shield-compatible, Raspberry Pi specific Arduino doesn't make much sense to me to be honest.

Where are the shields for the Arduino Nano, Mini, Micro or Fio? Nothing wrong with the form factor on those. Look at that Arduino Nano. It's beautiful!

[wirelessmonk]

There are over 290 shields (http://shieldlist.org) available for Arduino Compatible boards. Abandon the idiosyncratic header spacing for no reason other than proto boards and you ignore one of the benefits of using an Arduino compatible board. Incidentally, there are numerous Arduino Compatible prototyping shields available.

http://www.adafruit.com/products/51 $12.50
https://www.sparkfun.com/products/7914 $9.95
https://www.sparkfun.com/products/11665 $4.95 This is just the PCB, in case you have everything else you need.
http://www.newark.com/arduino/a000077/a ... 20Products $13.08
http://www.newark.com/arduino/a000082/a ... dp/76T4685 $3.74 This is just the PCB, in case you have everything else you need.
http://www.newark.com/arduino/a000083/a ... dp/44W8114 $10.79
http://www.mcmelectronics.com/product/83-13134 $4.99
http://www.mcmelectronics.com/product/83-15139 $8.99
http://www.mcmelectronics.com/product/83-13135 $9.99
http://www.mcmelectronics.com/product/83-14708 $15.99
http://store.fungizmos.com/items/184 $9.00
http://store.fungizmos.com/items/192 $16.00
https://solarbotics.com/product/51860/ $15.00 CAD
http://www.digikey.com/product-detail/e ... ND/3476362 $11.67

Incidentally, very little of the money ever makes its way back to the Arduino creators. If their aim was to make money on a proprietary pin-out... they failed miserably.

The Nano, Mini, Micro and Fio are each designed to be , mostly, breadboard compatible.

[Jim Manley]

I share the anger/dismay/teeth-gnashing about the 0.16-inch offset of the digital pins on the Arduinos. Here's Massimo's mea culpa as to how it happened:

http://forum.arduino.cc/index.php/topic,22737.0.html#13

It's the 14th post down on the page. Personally, I would have waited the extra week to get the correct alignment since it's not like they were going to lose any money on a non-profit project. This is just plain sloppy work, not professional engineering, in my book.

There are a bunch of ways around it, including this $1.25 adapter:


that's described at:
http://brettbeauregard.com/blog/2009/07 ... set-header

Note that this can be used to add a 0.1-inch perfboard as a shield to a stock Arduino:



or to adapt a stock shield to a perfboard iDuino with 0.1-inch spacing:



Here's a way to make your own offset adapter for the price of an eight-pin male header instead of $1.25 for the commercial bent-pin adapter:

http://www.instructables.com/id/Embaras ... rotoShield

I don't have much use for commercial shields, especially those that push the cost of an Arduino up well past $100 (e.g., WiFi, Ethernet, USB, etc., much less GPS), when much more capability is available on a Pi or even a Cubieboard, BeagleBoneBlack, etc.

If we get at least 1,000 orders for any particular configuration, we'll make them. "If you pay for it, we will build."

[panik]

Massimo is a good egg. I meant no disrespect.

There are workarounds, sure. But benefits? I don't see it.

I do see the benefits of a 'Pi specific Arduino', but in my mind that runs on 3.3V (like on the Gertboard), and isn't 'shield compatible'. I already have a shield-compatible Arduino that runs on 5V. It's the Arduino(compatible) boards we all know.

I also have various protoboards with Atmel microcontrollers running on 3.3V hooked up to the Pi. On 3.3V, it's the easiest thing in the world. A microcontroller, a crystal (if necessary) and some wires. No buffers, no voltage level conversion, no bootloader, no hardware programmer, no USB to serial interface, just hook it up and it works. Try running it on 5V however, and you're in a world of pain.

So in my humble opinion, if you want to make a Pi specific Arduino, then make it Pi specific. I'll buy it. But if it's going to be an Arduino clone with a 26 pin header added to connect it to the Pi where we have to jump through hoops to do the voltage level conversion (and 'pin-bending' or 'adapter-buying'), I'll respectfully pass.

[RaTTuS]

yeah make it all 3.3V
and then you can have RPI shield sized connectors - and that will become the default ...

edit
I've changed my mind
make it 100% compatible with the shield layout no need to be different

[mahjongg]

I do see the benefits of a 'Pi specific Arduino', but in my mind that runs on 3.3V (like on the Gertboard), and isn't 'shield compatible'. I already have a shield-compatible Arduino that runs on 5V. It's the Arduino(compatible) boards we all know.

I disagree, unless its somehow possible to configure to run at either 3.3V or 5V I would never design an "Arduino board" for the PI that runs on 3.3V. Also I would position the headers exactly as on any other Arduino board. The whole point IMHO is that only a 5V board with the exact same header configuration succeeds in the "golden grail", namely complete compatibility with all Arduino shield boards. The wrong distance between the headers is only a very small concern, and the whole Arduino community has learned to live with it, being incompatible with that is just silly. Also using 5V ensures that all the Arduino examples work, that there isn't a problem with putting 5V on the GPIO pins, and that the Atmel chip can run at the same (high) speed as the original. Atmel chips can only run on lower clockspeeds when you lower their working voltage.
As for the difference in working voltage between the PI and the Arduino, this is only a valid concern for the serial interface between the PI and Arduino, not a big deal.

[panik]

I would never design an "Arduino board" for the PI that runs on 3.3V

Gert did it, and look what it brought us.

The whole point IMHO is that only a 5V board with the exact same header configuration succeeds in the "golden grail", namely complete compatibility with all Arduino shield boards. The wrong distance between the headers is only a very small concern, and the whole Arduino community has learned to live with it, being incompatible with that is just silly.

That depends on the point of view. In my point of view, compatibility with Arduino shields means being incompatible with the rest of the world (everything non-Arduino). But maybe that's just splitting hairs. Anyway, I can't live with it and the Arduino community lost a member (oh, come on panik, cut the drama). Also, numerous official Arduinos have different form factors. Which one is THE one?

Also using 5V ensures that all the Arduino examples work,

There are numerous Arduinos that run on 3.3V (Arduino Due for example, but also one of the Pro mini and the Lilipads), and all Arduino examples work fine for those. 8 MHz is also an "Arduino standard" if I may call it that. With Gordon's patches, so is 12 MHz.

that there isn't a problem with putting 5V on the GPIO pins

Assuming you mean the Atmel pins, don't put 9V or 12V on them. People use those voltages too. GPIO on the Pi is 3.3V, it makes sense the Atmel uses the same. Don't put 5V on it. Why would you?

Atmel chips can only run on lower clockspeeds when you lower their working voltage.

Atmel chips can run on low clockspeeds at 5V no problem, but that's beside the point.

As for the difference in working voltage between the PI and the Arduino, this is only a valid concern for the serial interface between the PI and Arduino, not a big deal.

That's my main concern, and I consider it a big deal. That might not be the case for everyone, but I like to have the opportunity to use uart, spi, i2c and gpio between the Pi and the Atmel without headaches.

Also, with this line of thinking, I can plug in a standard Arduino (clone) in the Pi's USB port and start using it. No need for a 'Pi specific Arduino'. I believe that's what this topic is about, but that's up to Jim.

All this being said, I'm not here to derail the topic so I'll try to back off. Interesting points of view though. These 'shields' have a bigger grip on mankind than I imagined.

[gdt]

I've used the Freetronics LeoStick with the revised board RasPi model B. It plugs into the USB port. I quite like that as I don't lose I/O pins on the RasPi.