I've been looking for an alternative to Raspberry Pi for a project. Perhaps someone on HN can suggest a solution. Here's what I need:
- Run minimal embedded Linux (LAMP)
- No graphics/GUI required
- Ethernet connector
- Power connector for wall-mounted adapter (P5 or something like that)
- Serial port header for debugging
- Second serial port for other I/O
- Maybe a couple of LED's or an 8 bit port available for status LEDs
- SD card for OS (just like R-Pi)
- No other peripherals or I/O needed
- Low cost (ideally $25 or less)
Barring a pre-existing board, any suggestions for a low-cost processor to design a board around that could run a bare-bones LAMP setup? A lot of what I see out there (like the i.MX233) have built-in peripherals such as LCD and touch-screen controllers that would be overkill for this project.
Cost is about $22. Ethernet, Wifi, USB already working well with OpenWRT. Nice package manager. Real Linux at micro-controller price and power consumption.
You can lift some GPIO beyond the single light and button that comes on the board if you're clever with a soldering iron, but a generic Arduino Mini can make it sing for about $10 extra.
Yes, I'm very glad I found it. With the exception of graphics, it seems to deliver on all of the "maker promise" that originally excited me about the raspi, for a lot less, and with no issues actually getting hold of them.
I usually get them 10 at a time. Looks like the price went up to $26 :(
You can always try your luck on ebay. Looks like lots of vendors are shipping new ones from HK.
The '02 is just the '03 without a USB port and less flash. It can't fit OpenWRT.
Edit: Ahh. Looks like they superseded it with the TL-MR3020. The bad news is, it costs $33. The good news is that it has a software readable 3 position switch on the side that does seem supported under OpenWRT.
Be careful with model or even revision numbers, always check hardware compatibility lists. very often times the difference between something like a "653" and a "653+" can be an entirely different (and not supported) chipset.
So the question is what you're shooting for. You can build an embedded web server which has two serial ports, ethernet (or WiFi), power, 8 bit I/O port, and an SD Card interface for < $10. But it won't run Linux or MySQL or PHP or Apache. Instead it will run thttpd with a built in CGI type application.
I've got something very close to that from China which is trying to be USB over IP extender, but the basic setup is as you describe.
If you leave LAMP on your must-have list though it raises the price to at least $35 :-). Given the success of Rpi though I expect we'll see someone else's 'phone' SoC in a board (and no I don't mean Samsung's $200 thing)
Its not out of the question at all, my point (poorly made), is that LAMP costs $35, the reasoning is like this:
LAMP - Linux-Apache-MySQL-PHP, requires Linux which moves you into a memory managed core, Apache+MySQL adds memory requirements this puts you at 256MB minimum, 512M better 1G ideal. MySQL+PHP adds storage requirements (they are reasonably moot because an SD card can have 32G no problem). So the system requirements of the software, raise the cost of the hardware. If you buy that hardware in onesies quantity will cost you $50 - $75, if you can buy it in huge quantities its less, the RpI distributors can sell it for $35 but no idea what sort of margins they are getting.
Requiring LAMP is a "skills" play, which is to say it costs less to find a skilled programmer who can code inside a LAMP infrastructure than it is to find one who can code in an embedded infrastructure. That can decrease your time to market and your development costs. From a business perspective one would look at the total cost of developing the product and then the lifetime value at a given price. If you know that you over payed on the Hardware to get the skills advantage, then if you were doing a threat assessment to your market (part of a SWOT) you would note that someone who did it with an embedded programmer could come in and undercut your price and still make a good margin on units sold. This is exactly what Network Appliance did in the NFS server market, they ported NFS to the bare metal and sold a box based on the 486 that out performed a Sun 4 server at 1/10th the cost.
So if you are only making a few, the question is silly, $25 or $100 dollars won't make a big difference and there are lots off off the self solutions at the high end of the price range (PogoPlug, Guruplug, Etc, Marvell's whole effort there) If you have an on going market though, getting better margins per system pays off the longer you sell these things. You can compute the cross-over point with simple math based on salary of programmer, cost of goods, gross margin of the product.
Just saying "I want a $25 system that is LAMP based" is like saying "I want a car that costs what every other car costs except that it can fly." Which is to say, its a whine. You can also reason to a pretty good guess that a $25 LAMP system doesn't exist but looking around at Hacker News or a variety of tech themed web sites, You have no doubt seen all the press RpI got, and if you went back in time you could see the press the Dallas Semiconductor Tini (single chip web server) got, so you could reason that any LAMP capable system at that price point would hit all of the tech sites like a ton of bricks. It would take effort for it not to create a lot of news. So you can be reasonably certain it doesn't exist.
Now if you want to know why it doesn't exist, well you can figure that out too, take the Linux kernel and the efforts that have gone on to put it into small ARM chips, (there are lots to choose from) and look for the minimum viable chip to run Linux, then go to the manufacturer's web site and look at pricing (or use Octopart if its in general distribution). Look at the 1K price (that is "if you buy 1000 units") because it will be the nominal "street" price of the chip. Now price memory chips, ethernet magnetics, and board design/build. The PCB is going to cost $1 - $3 each depending most of these you can do in 2 layers but some designs really need 4 layers because the pin pitch is so dense. Then you'll want to find a place to make them. I'm lucky because living in the Bay Area I've got my choice of over a dozen shops that can make and assemble fine pitch printed circuit boards as a service if you're just making a hundred or so. When your run that exercise (at least when I do) I come up with between $35 - $40 per unit at about 1K units. Which, if I were to sell one to you I'd probably sell for between $75 and $150 depending on whether or not you were planning to resell them. To test my math I would go out and see if there were any products in that price range, and would find this one: http://www.adafruit.com/products/278 the 'chumby hacker board' which retails from AdaFruit for $89.
And then I would feel confident in asserting that no $25 system yet exists that supports a LAMP stack.
Well, they do exist as mass-produced devices that can be hacked. I am not inclined to do that. I've lived in that world in the past and it can be a minefield. Designs can change on you overnight and you are screwed.
Yes it is a bit of wishful thinking, agreed. I've been messing with embedded Linux for probably ten years on an off. It was very hard to get close to $100 in OEM board cost as early as three years ago. So, yeah, this ain't my first rodeo.
I posted the "wish" to HN because I've been out of the loop for about two years and just didn't know what's available. The iMX233 @ ~$5.00/100 (not thousand) is impressive enough. Still, not ethernet without going through USB first. That chip, as far as I can tell, seems to be the lowest cost potential to approach the $25 to $35 price range in reasonable quantities (100x to 500x boards).
A very quick calculation using mostly Mouser and Digikey --which are very expensive sources-- tells me that an iMS233 board should be doable for about $35 to $45. Keep in mind that this is by buying from the most expensive sources. I am always pleasantly surprised when I go to Avnet or Arrow for pricing. Sometimes your jaw drops to the floor. Digikey in particular is just about unusable for anything beyond prototyping. All of this tells me that the $25 number might be approachable with very smart and careful purchasing of all components and services. Going to China would certainly knock it down but you'd have to push larger quantities from the get-go.
I think I can consider an all-up cost of about $50, in the box and ready to go. This includes the assembled board in an very simple enclosure and a regulated wall adapter.
Right now I have a very mild itch I am thinking of scratching. Just looking around to see if it even makes sense.
"Well, they do exist as mass-produced devices that can be hacked." - Absolutely, that was why I mentioned my USB extender device, it too uses the A9X CPU that TP-Link is using. Nobody has yet seen fit to offer a 'general purpose' unit (ala the RasPi) for sale, but if you're willing to commit to the large volumes and upfront costs that are needed you can make a few hundred thousand.
"Designs can change on you overnight and you are screwed." - also exactly right which is why these aren't "parts" rather they are a lean way to bootstrap a prototype. Sometimes you can duplicate the OEMs design, sometimes they rely on side relationships, for example TP-Link builds a lot of stuff, so they may get a much better price on the A9X CPU than you could even buying a lot of them.
"I posted the "wish" to HN because I've been out of the loop for about two years and just didn't know what's available. The iMX233 @ ~$5.00/100 (not thousand) is impressive enough. Still, not ethernet without going through USB first. That chip, as far as I can tell, seems to be the lowest cost potential to approach the $25 to $35 price range in reasonable quantities (100x to 500x boards)." - Yup, and some chips like the STMicro 32F107 (Cortex M3 ARM) which has Ethernet on chip is under $6 in 100's but doesn't have the MMU. The A9X also has ethernet on chip but I've not been able to wade through the Chinese well enough to figure out what to order (these things power the $35 android tables in the back markets of China).
"I think I can consider an all-up cost of about $50, in the box and ready to go. This includes the assembled board in an very simple enclosure and a regulated wall adapter."* - You might be able to do that, but you may have a hard time find them in the retail channel for that. Even the RasPi is over $50 when you add power supply, case, SD card, and a serial interface.
"Right now I have a very mild itch I am thinking of scratching. Just looking around to see if it even makes sense." - Ah bingo! If you read nothing else, read this. I can guarantee that you will eventually be able to get this for $25. Build your idea out of any of a dozen different ideas (ideally one where you have good software resources or kernel support) and then you have "in your pocket" an idea that is almost ready to go if you can get the price down. Then you watch the channels, EE Times, etc and predict when the pricing is going to cross your threshold. Then about 6 months before contact the folks who are going to make that possible (chip vendors etc) and then partner with them to get early access. Then you can "ship" on the same day general availability hits.
Bottom line if the idea works don't worry what things cost right now, get the leg work done on stuff which has to be done regardless of chip availability.
The closest I can think of would be one of the Arduino ARMs or a Teensy or maybe a Stellaris. But I don't know if those have the "horsepower" to deliver a computing experience.
The Olimex is probably the closest I found too. I could see using their board for development and then doing my own to throw out all the hardware that isn't needed.
- Run minimal embedded Linux (LAMP) - No graphics/GUI required - Ethernet connector - Power connector for wall-mounted adapter (P5 or something like that) - Serial port header for debugging - Second serial port for other I/O - Maybe a couple of LED's or an 8 bit port available for status LEDs - SD card for OS (just like R-Pi) - No other peripherals or I/O needed - Low cost (ideally $25 or less)
Barring a pre-existing board, any suggestions for a low-cost processor to design a board around that could run a bare-bones LAMP setup? A lot of what I see out there (like the i.MX233) have built-in peripherals such as LCD and touch-screen controllers that would be overkill for this project.