EDuino - our vision of serial Arduino
Our vision of serial Arduino
We release here our serial Arduino compatible board: EDuino!! This project consists of a few versions of serial Arduino boards. A full featured Arduino is nice to use while developing projects, but when you make lots of projects it is a bit expensive to buy an Arduino board to be permanently installed in each one of them. Some other times, you would like to have a smaller Arduino. The aim of this project was to provide cheap, compact and easy to build boards that can be built at home and permanently integrated into projects. The PCBs are all single sided and the need to drill holes kept to a minimum (not to say none at all). The boards use a few SMD components but they are not hard to solder, consisting only of a few resistors and capacitors; soldering “big” (1206 size) SMD components is something that “barks” but doesn’t “bite” :).
All of this work is licensed under Creative Commons BY NC SA. And all images are clickable for a bigger view.
In the files you’ll find PDF files with schematic, PCB board, silkscreen and component placements. The board can be built with an IC socket and used with ATmega8, ATmega168 or ATmega328 in DIP package (the same used by Arduino). If you don’t care about Arduino compatibility then you can also use ATmega88 chips and the WinAVR toolchain to compile programs for it; the Arduino IDE comes with WinAVR bundled.
You will find the assembly of the components in the EDuino boards a bit uncommon; most of them are mounted SMD-like, although they are through-hole components. It’s actually quite easy to solder them this way, and that saves you the trouble of having to drill lots of holes on the board, which 1) takes time, 2) produces carcinogenic dust, 3) it’s worse for the environment and 4) makes you spend money on bits.
The connector pins on the boards are large pads so that one can solder a conector in “SMD mode”, make some holes and solder it as trough-hole, or simply solder wires directly driving cost down even more. We avoided SMD components as much as possible because they are harder to get, unless you don’t mind buying a few thousands, of course…
The “trick” to solder components using this technique is the same as soldering SMD components: first adjust the part on the board and then solder 1 pin on one end, followed by another pin on the opposing end. From then it’s easy to drop a tiny blob of solder on the remaining pins, because the component will not move.
See below what’s available. Enjoy!!
TTL <-> RS-232 adapter
This small adapter can be used to connect an EDuino to a PC serial port (a COM port), allowing it to be used in the Arduino development environment for program upload. This adaptor doesn’t support the /RESET line, which means that you’ll have to manually reset EDuino less than a second before starting to upload.
The adapter must be fed with +5V from EDuino, that’s why there is a +5V pin on it.
Download the project files: TTL / RS-232 adapter
There are 5 SMD 1206 parts in this board.
If you don’t have a PC with a serial port, you can buy an USB<->RS-232 cable and then connect this TTL<->RS-232 adapter, or you can buy an FTDI cable which works as a USB<->TTL converter and so it’s like a 2-in-1. To connect an FTDI-cable to an EDuino just follow this diagram:
This was the 1st EDuino to be designed. It is quite compact, taking into consideration that it’s routed on a single layer PCB without a single jumper. It has no pin 13 LED, and it’s almost square. There isn’t enough space for the 16MHz crystal on the copper side of the board so it must be mounted through-hole. A low profile crystal will take little space.
On a definitive project you can skip the IC socket and solder the ATmega directly to the board.
The reset button is a normal button but you need to fold the lead innwards and then cut them so that the button will sit on the board strait. The small leads remaining are enough to solder it to the board. You must solder all its 4 leads.
Download the project files: EDuino v1
There are 5 SMD 1206 parts in this board.
EDuino-B - EDuino breadboard
After the 1st EDuino we started to think that maybe the perfect solution was to have a set of PCB designs and use the most appropriate for each project. Then EDuino-Breadboard came along. It has all pins on the same side of the board, and can be fitted in a 390 dot solderless breadboard, taking only one side.
The LED is a normal 3mm round LED and is equivalent to Arduino’s LED at digital pin 13. Within a minute you can fold it’s pins in such a way that it will be easy to solder SMD-like.
The component side of the board is basically free, so you can glue a piece of paper with whatever drawing you like… you know, imagination is the limit! (we would love to see your suggestions for this area). A hole was made for the LED in the boards below, but when using 0.8mm thick PCB the light going through the board is probably enough for most situations. And if it isn’t, you can always use a high brightness LED. Nevertheless, be aware: it shines on you!
Download the project files: EDuino-B v1
More photos (click!):
There are 6 SMD 1206 parts in this board.