Signal and Brake Module hardware

Hardware

The hardware for this signal and brake module, as it is presented here, uses a lot of surface mounted components. I have only done this to keep the size of it down. There is no problem in you making your own modules using only leaded components. Look further down on this page for a non-smd version.

The only truly critical component in this design is the AVR processor, as the software is written specifically for this one. It is a new AVR type from Atmel, just coming out to the general public here in the beginning of 2005. Though it is faster and more advanced than its predecessor (the Mega8), it is quite a bit cheaper, and really helps keeping the cost of this module down.

The rest of the components are not critical, and can be replaced with numerous other similar ones.

Files

Bill of Materials
This is the components needed to build this signal and brake module.
Except for a printed circuit board, it is all there.

Tips and tricks for building the module

As I mentioned above, I have used a lot of smd parts in this module. You do not have to do the same if you don't want to. Of course if you want to use the PCB without redesigning it, you probably have to do it anyhow. But feel free to redesign the PCB board to use through-hole components all over the place. Or make your own PCB from the ground up. Or use a prototype board. Quite a few board-houses around the world can make PCB's directly from the Eagle BRD file, available above. Other manufacturers requires Gerber files, which can be generated with Eagle. The BRD file has been optimized (drill sizes, track/clearance and silkscreen) for prototype production at Olimex.

The bill of material list has a column with order codes, so you can easily find everything at Elfa. That is where I usually get most of my electronics from. I have used only standard components, so you should not have much trouble finding them (or equivalents) somewhere local to you.

If you do not want or need feedback to a s88 module, then you can skip R18, R19 and OK3. This will make the module a bit cheaper to make.

Making a module without surface mounted components

After several requests, I have made an example module using leaded components only. Please note that I haven't tested this construction in any way, and there is a chance that it does not work. However, I don't think there is any problems, as it has been based on the original plans above.
Also, the PCB is just a quick'n'dirty work, that hasn't been optimized for size or anything. Feel free to design a more compact version, and I'll be happy to publish it here, if you'd like.