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I’m currently doing a project for one of my classes, and since I’m in charge of anything involved in electronics for the whole project, I decided to make a board that would allow me to use an ATmega8 or Atmega168 (since there is a possibility that the Atmega8 memory will prove insufficient) in a protoboard.

The concept is old, and there is a bunch of others great solutions out there, like the Boarduino, RBBB, Alex from Tinkerlog has even made one in a prototype board. All this examples work great and would solve the problem for me right way.

But, you know, I never did like to do any-thing simple when I could do it ass-backwards. (A virtual coke to anyone who gets this quote)

And since i don’t live in the USA or Canada, ordering a Boarduino or a RBBB would take to long and the shipping would be expensive. I could do like Alex and make one on a protoboard, but since i will probably need five boards if the project works i prefer to spend some of my time and make then on Eagle.

Overview

• Single sided PCB
• Plugs into a breadboard
• Practically all pins are brought out, except reset, power and clock pins
• Power good led
• Reset button
• 6-pin standard ICSP header
• Atmega8 or 168 working at 16.00 MHz with an ceramic resonator (which is precise enough for UART communication)
• Arduino compatible
• 6-pin connector for a USB-TTL cable (with auto-reset capability)
• USB or External power, jumper selectable

Schematic

The schematics is basically the same as Boarduino and RBBB, without the power supply.

It has an ISP connector to program the chip, (if you intend to use it as an arduino, you will have to program the bootloader and the fuses) and a serial connection for the USB-TTL cable, that is used to communicate with an PC or/and used for uploading Arduino sketches.

Board

You shouldn’t have problems with soldering everything, but there is a few tricks that might help you along the way.

1 - Whatever you do, solder the jumpers first. There is one right under the ATmega connector and you don’t want to forget that he is there,trust me.

2 - If you use regular header pins connectors, you will notice that they don’t leave much space between the board and the breadboard, there is two ways to fix this.

One is using header pins that are bigger, there should probably be some on your local electronics supply store.(The ones on the left, as you can see, are bigger)

The other one is to press the pins on a normal header connector with a plier making the pins pop a bit. (The picture should explain this far better than I can)

3 - Be careful, specially if you made the board yourself.
When removing and inserting the board on a breadboard, go easy, grab both ends of the board and gently push/pull back and forth.

4 - Check everything after you have finished soldering since there could be a lot of solder bridges that shouldn’t be there.

External Power

Since the board doesn’t have a voltage regulator you will have to provide regulated 5V to the board, for that, there is a 3 pin connector, with the middle being the 5V and the other ones being ground, that way, if you use a female 3 pin connector, it doesn’t mater the way you connect as long as you in deed connect the 3 pins.

Is also possible to solder a 2 pin male molex connector, which would also prevent you from inverting the power.

Using as an Arduino

Well, the board was designed to be arduino compatible, but since i never used arduino, I don’t fell confident to explain to others how to program the ATmega with the bootloader and how to configure the fuses.
For that, I recommend you to read this project from thinkerlog that have a excellent how-to on this.

Download

The schematics and the board file in eagle format.
The schematics in PNG.

These are released as-is under
Creative Commons 3.0 - Attribution - Share Alike

Conclusion

The board serve its purpose, its compact, fits nicely on a breadboard, its easy to make at home and will help a lot on the prototype days to come, the only thing missing is a power supply, but I’m currently making a new version that will have one so stay tuned for more updates.

This entry was posted on Friday, October 31st, 2008 at 21:16 and is filed under ATmega8, Arduino. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.