The Frienduino is an Arduino clone you can make for a friend once you have any kind of Arduino and some soldering skill. The board is easy to make (single sided) and easy to solder (only through hole components). It has everything to get started yet it is cheap and simple because it saves on stuff the novice doesn't need (separate power supply and 3.3V regulator).
IMHO, what made the Arduino so popular is its USB connectivity. This lowers the entry barrier to near zero. No messing around with programmers, no legacy serial port required. Alas, most of the many many Arduino clones out there lack this key feature. I guess the reason for this is that, until now, all USB to serial adapters were not available as a through hole component, thus discouraging the novice to build a "true to the spirit" clone on their own.
It may seem odd at first to use a programmable micro controller just as a dumb USB to serial converter, but if you look at the price tag and consider it's the only way to get USB to serial as a through hole part it makes a lot of sense to me. And not to me alone. The folks over at UNL Maker Club must have had a similar reasoning when they chose the 16F1454 as the USB adapter for their Innovation Board, an all SMD Arduino clone.
Windows users will find the driver .inf file in this repository. If you connect your ready to use (firmware flashed) Frienduino to a USB port and Windows refuses to identify it as a virtual COM port, go the hardware section of your system configuration and manually update the driver. When asked for the new dirver file point to the inf file supplied in the repository.
Linux users should have no problem. The driver should be automatically installed. But maybe you will have trouble using the serial port created by the driver. In this case you will have to run the Arduino IDE as root or better create a rule to allow ordinary users to use the port (TODO: add link to advice on creating a USB rule file).
The schematic and PCB are a copy of the Arduino Duemilanove reference design modified to be a single sided layout using the 16F1454 as the USB adapter and striped off the external power supply. Reset button and ICSP header were moved for better accessability and less complicated routing respectively.
If you intend to have the Frienduino PCB made, there now is a ready to use gerber file in the repository. If you want the PCBs made by http://www.seeedstudio.com you can even uses this ready to order project.
For German hackers I have prepared a public reichelt shopping cart with all the parts needed here. It totals to 7.78EUR.
The pre-compiled firmware to turn the PIC 16F1454 into a serial adapter can be downloaded from this repository. To flash the .hex-file to the PIC you can use a second Arduino board and some jumper cables using the soft- and firmware from this repository. With this special version of the original programmer you can program your PIC in low voltage mode removing the need for a 9V programming voltage and making programming the PIC as simple as programming the atmega.
To flash the PIC, you first have to flash a second, ready for use Arduino (or Frienduino) with the special PIC-flashing firmware found in the repo's "ProgramPIC" folder. Then you have to compile the flashing host program in the "host" folder by typing make in the console (this is assuming you have gcc resp. MinGW installed).
Then you have to connect
- pin 5 of the PICs ICSP header to digital pin 4 of your programmer Arduino
- pin 4 of the PICs ICSP header to digital pin 7 of your programmer Arduino
- pin 1 of the PICs 5x1 ICSP header to analog pin 1 of your programmer Arduino
- pin 2 of the PICs ICSP header to +5V of your programmer Arduino
- pin 3 of the PICs ICSP header to ground of your programmer Arduino
Then you have to run ./ardpicprog -p /dev/ttyACM0 --erase --burn --input-hexfile PIC16F1454_USB2Serial.hex in Linux, or ardpicprog.exe -p COM1 --erase --burn --input-hexfile PIC16F1454_USB2Serial.hex in Windows in a console in the flashing program's folder (assuming you copied the firmware hex file to this folder, and that the second Arduino is connected to the /dev/ttyACM0 resp. COM1 port). The flashing program will then identify your PIC as a 16F1454, erase it and then burn the new firmware (this will take a while). When the flashing program finishes you're done and can disconnect all jumper cables before you move on to flash the Atmega.
In order to make our Atmega Arduino-compatible you have to flash it with an Arduino bootloader. To do this, you can use a second Arduino board and follow these instructions. In the Arduino IDE you have to choose "Arduino as ISP" for the programmer and "Arduino Duemilanove w/ Atmega328" as the board.