Thursday, December 23, 2010
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Arduino Breadboard construction

Arduino Breadboard


ArdunioBreadBoardCloseLabledHere is a truly barebones Arduino setup. Just the Arduino chip and a few support parts. This has to be close to the simplest and lowest cost way to play with microcontrollers. The only special parts are the resonator and the Mega168 programmed with the Arduino boot loader. Everything else you should already have as an electronics hobbyist.

You will need a way to talk to the Arduino. I talked about the serail interface in a recent post. I used a FTDI TTL-232R USB to TTL Serial Converter Cable. This cable has a USB to TTL serial chip built into the USB connector. The other end of the cable has a connector that can be adapted to the bread board using a 5-pin header. The FTDI cable cost $20 and works with the Modern Device Arduino Compatible Barebones kit. Because the USB adaptor is in a cable which be can unplugged, I can use it in other experiments like this one.


Take a look at the picture above. I tried to label all the interesting bits and will provide some more description here.

The Reset PB is the strange hacked up thing at the end of the Mega168 chip. I had some scrounged PCB mount pushbutton switches which don’t stay seated in the breadboard so I soldered up an adaptor using a chunk of protoboard and some 3 pin headers. This mounts solidly and stays put.

Here is the list of parts I used with some suggestions for sources.

ATMega168 from Modern Device Company for $5
The Mega168 is an AVR microcontroller which has been programmed with the Arduino boot loader. The chip is available for $5 from Modern Device Company. I also give them away for a link to this site.

16Mhz Resonator from Digikey for $0.24
The one I had came from spare parts in the Modern Device Kit pack I purchased. Perhaps Modern Device Company will sell the resonator along with the chip in the future. I found one at digikey for $0.24, less then a quarter. If you dont have a resonator, I will include one with the chip if you take advantage of the link to uC Hobby offer .

Reset Push-Button scrounged for free.
You can scrounge all the switches you will ever need. A good source is old PC cases. The reset button in a PC case is a momentary push button and even has a nice cable with a header style connector on the end. Mine was scrounged from some old gadget.

Red LED from Alan’s Electronics Projects
I have plenty of LEDs thanks to the giveaway kits I have from Alan’s Electronics Projects. These LEDs are very high brightness on low current so they are ideal for direct connection to a microcontroller. I still have a few kits to give away if you need LEDs. If you need some lab stock, I highly recomed Alan’s kits. You can also still get one of these kits by linking to uC Hobby from you electronics related hobby site or blog.

Resistors from All Electronics
Two 1K and two 10K resistors were used from my bench stock. I purchased several resistor assortment kits from All Electronics for $11.50 for 610 resistors. I sorted the resistors into a plastic drawer cabinet to make them easy to find. These kits are cheap and you really should have a good assortment of long leaded resistors for breadboarding and general electronics hobby work. You can scrounge up resistors but they usually have very short leads and are not of much use with breadboards. Much of the components, tools, and test equipment I have was purchased at All Electronics , I highly recommend that you browse there.

Breadboard from All Electronics for $88
I used a powered breadboard purchased from All Electronics. This breadboard has a +5 and two adjustable power supplies built in. It is very convenient for prototyping work but you can use any breadboard for this work. The +5V supply you need is provided by the USB interface cable. Or you could use a scrounged wall wart . Just to be sure, I powered my Arduino from the USB so I know it will work for you.

If you need a cheap breadboard that has room to do some great work I recommend thisbreadboard from All Electronics. I used the bigger version for the supper bread board mentioned in this previous article.

TTL-232R from Modern Device Company for $20
This is a great solution for connecting your microcontroller projects to the PC. The TTL-232R has a USB to serial interface chip embedded in the USB connector. The other end of the cable has a 5-Pin connector that will mate with a standard header. I inserted a header style male into this connector to adapt it to the breadboard. The connector was scrounged so it was free. You could cut the connector and wire to a header or make some adaptor using scrounged parts.

I used the schematic shown in the Modern Devices Arduino assembly instructions. I only needed the circuits that implemented the resonator, the TTL/USB serial interface, and Reset button. I connected a 1K resistor from pin 19 (D13) to the LED for the Blink test program.

Initial Testing:
Before you put power to the chip, double check the power connections. Check every connection to the power supply (+V and GND) rails on your protoboard. With the USB serial adaptor disconnected apply power, the LED should light up instantly and flash a bit as the boot loader starts up. If you don’t see the LED turn on, switch off the power and do some more checking. You may just have the LED in backwards. You can confirm the LED works and it’s proper direction by making a separate circuit on the breadboard that simple lights up the LED.

If you are using the USB adaptor for power then you will just have to risk it. I recomend that you triple check everything. If you have a major problem your PC may inform you that a USB device has exceeded the supply current limits. Check everything over again and power off and back on your PC.

Once everything checks out, turn it off and connect the USB serial adaptor. Load up the Arduino development environment and get the Blink example. Download it to you chip and watch the LED flash. If you get to this point, you have a good breadboard setup and are now ready to start your microcontroller experiments.

Final Thoughts:
I hope this article shows how easy it is to get started with microcontrollers. If you have a hobby related web site or blog a link to uCHobby will get you a programmed Arduino chip to play with. You can also choose the Arduino PCB board instead. If you submit an article about you projects to uCHobby which we can publish then we will send you a full up Modern Device Company Arduino Compatible Bare Bones kit. You can read more about the giveaways here.

Let me know what you think of this article with a comment. Do you like these kinds of articles? Any improvements? Suggestions for future projects to do at uCHobby? One idea I have been considering is to start a regular set of articles about setting up a home electronics lab. Would this be of interest? Have any suggestions about the tools, parts, etc…?

Related posts:

  1. Free Arduino Microcontroller Kits.
  2. Arduino LCD Interfacing Part 1
  3. Arduino kits are here
  4. Arduino AVR In System Programmer (ISP)
  5. TTL to RS232 adaptor Explained