Step 5: Some Caveats:

** Caveat #1 : The reason this trick works is that, unlike most Arduinos, the Lilypad Arduino is clocked by the ATMEGA's built-in oscillator instead of by an additional crystal oscillator circuit. This lack of additional oscillator circuitry makes wiring up the circuitry a lot simpler, but as a result the chip runs slower (8MHz instead of 16MHz) and its timing is not as accurate. The lilypad bootloader knows how to compensate for this speed difference to make sure all of your delays and baud-rates and other time-sensitive functions work correctly, but the fact remains that the chip will perform slower.  This is not a big deal unless your application needs very accurate timing or needs to perform tasks very quickly.

 If you do need your Arduino to run at the proper 16MHz speed, use two 22pf cermamic capacitors and an Abracon ABL-16.000MHZ-B2 crystal oscillator, and connect them as shown in the figure above. If you do decide to use this 16MHz crystal oscillator setup, don't use the Lilypad bootloader -- just use the correct bootloader for the board you have (eg diecimila, duemilanove, uno etc).

** Caveat #2: The ATMEGA chip has weird names for its pins -- ie ATMEGA pin 1 is not necessarily Arduino pin 1.  So you need the chart above to translate (courtesy of http://arduino.cc/en/Hacking/PinMapping168 )

**Caveat #3:   Whatever power supply you use (cell phone charger, usb jack, or AAA batteries are quick and easy methods) it may not be a perfectly solid 5V.  So if you have problems with the chip hanging or resetting unexpectedly, add a .01 uF capacitor between 5V and Ground, as close to the chip as reasonably possible.  This filters out noise on the power supply.  You can also add an additional 10uF electrolytic cap in the same place (noting the polarity markings on the capacitor) --this protects against disruptions in the power supply.

**Caveat #4:  The most expensive and complicated part of an Arduino is the serial-to-usb circuitry.  By omitting it,  we save a lot of cost and effort, but If you still want to use your ultra-bare-bones arduino to communicate using the normal Serial.print() commands, you will need to purchase a 5V TTL USB-to-rs232 adapter cable, and connect it like so:
Cable TX wire   --->  ATMEGA Pin 2 (RXD)
Cable RX wire  ---> ATMEGA Pin 3 (TXD)
Cable Gnd wire  ---> ATMEGA Pin 8 (Gnd)
<p>Great guide!</p><p>For Caveat #4, how about taking this instructable one further and building your own RS232 adapter using another cheap microcontroller with a USB interface ;)</p>
<p>hi, i am using arduino with firmata skecth, is it possible to use firmata on an atmega?</p>
cool, OK, thanks for the effort<br>but just to clarify- arduino IS really cheap nowadays...<br>https://sites.google.com/site/arduinouk/ ?
<p>When building a permanent circuit though, who wants to use a whole arduino to power it? Better to just use the programmed chip, which is what this is about.</p>
What you are most likely doing when you throw the lilypad loader in is simply setting the fuse bits so that it will run off the internal clock. <br>Add an external crystal, and a couple capacitors for good measure, and you can take the ATmega328P off the Arduino and make a circuit just like yours, and it'll work - AT TWICE THE SPEED that yours does. If you set the fuse bits so that it uses the internal 8MHz clock, even with the Arduino bootloader, your circuit would work. It's about the clock, not the bootloader. If you want to make it much more friendly, add an ICSP header, and a header strip for the pins so you can still prototype, and then you have something really useful. If you have made a project on the Arduino you really like, use your circuit with a 16 MHz crystal across the XTAL pins, with a 22pF cap from each pin to ground, and you can take the chip off the Arduino board to make your project have it's own dedicated processor without taking up your expensive Arduino board. <br>Here's a couple boards I made - one with an Arduino, and one with an ATmega32A
If you're asking &quot;Where does the power go&quot; - well, you can power it from your programmer which plugs into the 10 pin header, or you can just hook power into pins 2 (+Vcc) and any of 3, 4, 6, 8, or 10 (GND) of the ICSP header. If you are wondering about the 2 capacitors on the mini-duino, they are on the bottom. I developed these for my first prototype of<a href="http://www.instructables.com/id/CHRs-8X8X8-LED-Cube-Revisited-with-improvements/" rel="nofollow"> the LED cube</a>. Since ALL the drivers and transistors etc. were all on my prototype controller board, I made these so that I wouldn't be limited by only 1 kind of microcontroller. I eventually then made a single controller that allowed either of these chips on the same board. I kept these controller boards for prototyping though, and they work great! They are also great for pre-programming chips for people or fixing the fuse bits.<br> <br> If you're now wondering what the heck the LED cube is, you can see it in action here.<br> <br> <div class="media_embed"> <div> <object height="350" width="425"><param name="allowscriptaccess"><param name="movie" value="http://www.youtube.com/v/qp6BRFKT2Qk?autoplay=0"><param name="wmode" value="transparent"><embed height="350" src="http://www.youtube.com/v/qp6BRFKT2Qk?autoplay=0" type="application/x-shockwave-flash" width="425" wmode="transparent"></embed></object></div> </div> <br>
why don't just buy cheap arduino? <br>https://sites.google.com/site/arduinouk/<br>I mean, OK I get the idea, but it got really cheap...
<p>Would you mind making an instructable on making one of these boards, please?</p>
Whit a 16 k ressonator you don&acute;t need the capacitors and you can run at normal speed.. so all your scripts will run with no problems. Don&acute;t forget that all arduino ide uses 16 mhz and not 8 mhz....
The ATMega chip will run on a 8MHz crystal though, it will just process information slower.
Agree.. but the problem is the arduino IDE .. not the fact that it does run or does not.
<p>Sorry pal, that is bad information you are giving out.</p><p>There are certain AVR chips that run at 8MHz that aren't supported, but there are 8MHz Arduino that are, as you can see:</p>
<p>Now it is.. 3 years ago...no... as you can see my comment was not made yesterday...</p>
<p>You can find cheaply here:</p><p><a href="http://www.mivarom.ro/catalog/advanced_search_result.php?keywords=ATMEGA&osCsid=rsjqd3prh88v39boj272rr33j7&x=43&y=7" rel="nofollow">http://www.mivarom.ro/catalog/advanced_search_resu...</a></p><p>Or at least for reasonable price. It's a Romanian site, but they might send in other countries as well. The cheapest orders have to be around 7 $ US </p>
<p>The 328P is 10 leu - about US$3.</p><p>For less than US$3 you can get an entire Arduino Nano with free shipping...</p><p>http://www.aliexpress.com/item/1P-HOT-USB-Nano-V3-0-ATmega328P-5V-16M-2014-Micro-controller-Board-For-Arduino/32258251789.html</p>
<p>Hello Everyone, I live in Brazil and where I live is very dangerous ... I mean people steal you everytime is like Gran theft Auto sooo I want to make a Cheap gps tracker for me and my fellows, I can use this $3 arduino and put a gps to work in this ?<br>do anybody have a link from a cheap gps too and a tutorial about how to make it?</p><p>Ive seaching during a long time for a project to make<br>.. Very Thanks and Help me please!</p>
<p>Yeah! but you also need a GSM shield for communication. Check this out: http://www.instructables.com/id/Athena-The-Global-Car-Tracking-System/?ALLSTEPS</p>
<p>Hello the shield is so expensive im trying to find a way to make one less expensive<br></p><p>the shield is 160 reais = $ USD 70 and a car tracker in the web shop u can find for is 100 reais = 50 $ USD <br></p><p>ive found <a href="http://www.instructables.com/id/Arduino-Mini-Shields/" rel="nofollow">this guy who make mini shield</a><i> </i>so im trying to figure a way to make one with the function of the SIM900 GSM/GPRS Shield Module<br>I also found this <em><a href="https://store.open-electronics.org/index.php?_route_=GSM_GPRS_GPS_SHIELD" rel="nofollow">16.20&euro;</a> </em>gsm/gprs &amp; gps shield</p><p><br>but still expensive cuz libras are more valuable than dolar one libra costs 3,70 reais </p>
<p>US$16 - complete GPS/GPRS tracker: http://www.aliexpress.com/item/Hot-Sale-MINI-Portabel-Realtime-monitoring-GPS-personal-locator-GPS-GSM-GPRS-gps-tracker-car/1962061750.html</p>
<p>* 80 $USD = 160 reais</p>
<p>Forget this 4 year old tutorial - you can buy an entire Arduino for US$2-$3.</p><p>And there are SIM900A+GPS modules for about $8.</p><p>The two of those, plus an antenna, power connector and a box to store it in, should only cost about $20 in total.</p><p>Or... buy one that works out of the box for $16 delivered to Brazil: http://www.aliexpress.com/item/Hot-Sale-MINI-Portabel-Realtime-monitoring-GPS-personal-locator-GPS-GSM-GPRS-gps-tracker-car/1962061750.html</p>
<p>I know this is from ages ago but check this out: http://b.leppoc.net/2011/04/23/operation-lo-jack/ If you have a simcom module and a UNO you're most of the way there. Then pick up a cheap GPS serial receiver for a few $. Just remove/leave out the RFID stuff and have a simple switch or something.</p>
<p>THE PINOUT!</p><p>oh my gosh thank you for the pin conversions! Throw one of these on a breadboard, ftdi it, lil bit of fiddling and its an arduino! thanks for figuring this out, &pound;45 per project i wanted to leave implemented was getting really restictive </p>
<p>While in 2010 this was correct, now It is more expensive than buying an Arduino.</p><p>You can buy a complete 16MHz Nano or Pro Mini for about $3. With USB, power rectification, SPI, LEDs, all that good stuff.</p><p>If you were paying 45 quid for your project 2 months ago, you aren't shopping smart. I only pay US$8 for a Mega2560. Don't be suckered in by European prices - import your own.</p>
<p>What is the cheapest option for arduino + wifi? I want to add arduino devices to my cloud. :)</p>
<p>The cheapest wifi I have found is the ESP8266: http://www.instructables.com/id/Using-the-ESP8266-module</p>
<p>You probably don't want to go with wifi, its way expensive. I'd suggest getting an ethernet module, they go for $3 on eBay. Since the IC is so cheap, you could just grab a few transmitters and have them interface with the cloud through the one. It's what I plan on doing :)</p>
<p>+1</p><p>or if you want a lot of devices connected, just get one Ethernet module and (then the hard part) write your own spi communication procedure and have all the decives comunicate with the one connected the the Ethernet for relay onto the cloud. Kinda your own mini cloud</p>
<p>You're so right man... u.u,</p><p>Everyone should know it. +D</p><p>Thanks for sharing!</p>
<p>While your $3 really cheap arduino was a great idea when you wrote it, I now buy Arduino Pro Mini's, headerless (but with included headers if I want to use them), for US$2.</p><p>So that's a complete Arduino, with LEDs, voltage regulators, etc. for just $2.</p><p>For another buck I can buy a USB-equipped Nano v.3.0.</p>
<p>Whoa man, send me a link?</p>
<p></p><p><a href="http://www.aliexpress.com/store/product/Free-Shipping-new-version-5pcs-lot-ATMEGA328P-font-b-Pro-b-font-font-b-Mini-b/1270362_1884115096.html" rel="nofollow">http://www.aliexpress.com/store/product/Free-Shipp...</a></p><p><a href="http://www.aliexpress.com/item/Free-Shipping-4pcs-in-stock-Nano-3-0-Atmel-ATmega328-Mini-USB-Board-with-USB-Cable/1896255616.html" rel="nofollow">http://www.aliexpress.com/item/Free-Shipping-4pcs-...</a></p>
<p>Thanks for that :)</p>
<p>No worries. There are a bunch of sellers selling the same boards.</p><p>Personally, now I buy &quot;Baite&quot; boards - they seem pretty good - well made, reliable, etc. They are about a buck more than the ones I sent the link.</p><p>Baite is the manufacturer, they also sell on Aliexpress. I have bought their boards cheaper from other sellers, but the guy at Baite will discount if you buy a few. He was the one I paid $2 from.</p><p>http://www.aliexpress.com/store/812021</p>
<p>So the quality is good? (for a cheap clone)- and they come with the bootloader installed i assume? and maybe the usual fuse to avoid damage to host computer? :)<br><br>Thanks for the help, ill definitely pick up a uno first; but i would much prefer something i can just leave in my projects :)</p>
<p>Good quality board, bootloader installed and dunno about the fuse... cant see anything on the schematic.</p><p>Not that technical, sorry. </p>
<p>can any one help me out! i have the Arduino Duemilaove with 328p microcontroler. i want to make a really cheep solution i want to run two servos in sweep with just the microcontroller. and can seem to figure it out can someone give me some suggestions? </p>
<p>so this is the ''clone'' of the arduino duemlianove with the same features?????</p>
Thanks, this is what I am looking for.
Personally I find it much easier to just make a chip w/ a 16MHz clock and be able to put any old boot-loader on it. I like using optiboot, a sketch that allows you to use your arduino (I use an uno) to bootload a chip. Then you can just stick that chip in the arduino to program.<br> <br> The cost isn't that much greater:<br> <a href="http://www.mouser.com/ProductDetail/Atmel/ATMEGA328P-PU/?qs=sGAEpiMZZMtVoztFdqDXO6rEZqxeooRg" rel="nofollow">ATMEGA328P $2.24</a>&nbsp;<br> <a href="http://www.mouser.com/ProductDetail/ECS/ECS-160-20-46X/?qs=sGAEpiMZZMvAbnEMxb34PXdofEOmSFR5" rel="nofollow">Crystal 16MHz: $0.46</a>&nbsp;<br> <a href="http://www.mouser.com/ProductDetail/Xicon/140-500N5-220J-RC/?qs=sGAEpiMZZMsh%252b1woXyUXj3vaHGRyT6H%2f44jcnFnrLhk%3d" rel="nofollow">(2 )Ceramic Disc Capacitors 22pF: $0.22</a><br> Optiloader: free sketch<br> Total: $2.92 for a 16MHz microprocessor running standard arduino bootloaders. Can be bootloaded and programmed w/ a $30 UNO.<br> <br> Now I just want to find a cheap battery solution. I wish they sold 5V a dime a dozen like AA. If anyone knows of anything let me know. I'd prefer to just have to hook it up w/o any other wiring.
Would three 1.5V batteries for a total of 4.5 do the trick?
<p>use a portable cellphone charger. the ones with usb ports on them. they work great and the 1.5 v batteries might not work well, some of these chips are pretty specific. i wouldn't risk the damage (regardless of how cheap). you can use 6V or 9V if you buy a 5v regulator (just as cheap as other stuff).</p>
Scratch that, <a href="http://www.mouser.com/ProductDetail/Xicon/140-50N2-220J-RC/?qs=sGAEpiMZZMt1mVBmZSXTPPQUnq7ol7tGHumVR2AvatM%3d" rel="nofollow">8 cent capacitors</a>
I cant seem to burn a bootloader onto the atmega168U-20PU <br>I seem to not have the correct boards.txt that support the version of the 168P-20PU <br>or is there a other reason for returning a wrong Device signature ? ( Using Leonardo as ISP ) <br>fault description <br> <br>avrdude: Device signature = 0x1e940b <br>avrdude: Expected signature for ATMEGA168 is 1E 94 06
Chip where I live cost $24!!!!!
Try ebay.com you can find 5 chips for about $12
&quot;This is not a big deal unless your application needs very accurate timing or needs to perform tasks very quickly -- in which case you can add a crystal oscillator and two capacitors to make it run at the proper 16MHz speed.&quot;<br> <br><strong>In regards of this quote from the tutorial, can the ATmega chip be clocked by a faster crystal, say, 40MHz, or is 16MHz the limit? Thanks!</strong>
My dad told me that overclocking can mean overheating. So you can, but you'll need the proper cooling.
Also, the limit is actually 20MHz for Mega168 and Mega328. (Arduino boards that take a microcontroller with the Mega8 footprint run at 16MHz because that is the limit on Mega8.)
1 atmega8-16pu = 1$ <br>It's the same thing than an arduino but it only has 8kB of flash, bust trust me, it's enought for most of you projects. I have a bunch of them and put them everywhere.

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