Another USB relay controller

**W3bMa5t3r** · 05-22-2006, 09:15 AM

Originally Posted by Rickertsen2

Here are some pics of the board i made:

The top
http://geargrinders.net/james/usbr/s001.JPG

The bottom
http://geargrinders.net/james/usbr/s002.JPG

Sweet, that should be easy enough to solder and with the directions you gave for making the board this should work great.

lol I'll just have to rely on the rest of you guys for the software side

I just noticed too, your board/circuit gives the option of normally open or normally closed for the relays. That is sweet, since the few other usb relay boards I've seen are one or the other.

**MatrixPC** · 05-22-2006, 10:03 AM

Originally Posted by Rickertsen2

It turns out, making a board isn't as hard as it sounds. I found a method that is pretty easy. It doesn't look like it should work well, but in actuality works awesome. I found it Here. I will summarize the process.

I used that Staples paper and Lazer Toner transfer to build the PCB for the Sproggy PSU.
It came out really clean

**davesaudio2** · 05-22-2006, 03:47 PM

Have you calculated the trace widths required for the 15amps?
many board houses also do small production runs.
Microchip also have a small scale pre programming service.

**shotgunefx** · 05-22-2006, 03:53 PM

Have you looked at http://www.expresspcb.com ?

A good alternative if you don't have the time to learn eagle. It looks like you might be able to fit in on a mini-board. If so, 3 for $51.

I've used their service and was quite happy.

Here's a pic of the rgb led driver boards I made. I had to pack it damn tight though.

**Rickertsen2** · 05-22-2006, 06:53 PM

Thanks for you interst everyone.
I got the parts today and assembled them (mostly). The USB connector is lying beside the board, because i routed the traces wrong, and most of the connectors are missing because DigiKey sent me the wrong thing.

Here are some pics:
The top

The bottom with the SMD components.

I tested all the hardware and it seems to work. Time to get programming!

Originally Posted by davesaudio2

Have you calculated the trace widths required for the 15amps?
many board houses also do small production runs.
Microchip also have a small scale pre programming service.

I did not do the calculations but it is something i am thinking about. As you can see in the pics, the power traces are covered in a thick layer of solder which makes up most of the cross sectional area. If/when it ever goes into or a kit or production, i will fill all the available space. What i really need to know is what kind of volume small kits like this are usually produced in. I figure I would need at least 10 to make a kit for mp3car people worthwile and at least 100-500 to make an assembled product. Relay boards are useful to more than just carputer people.

btw shotgunefx, that RGB driver is pretty sweet. I've been contemplating a similar project.

**LowLux** · 05-24-2006, 05:00 AM

any updates?

**Chris31** · 05-24-2006, 12:26 PM

Just out of interest, have you tried turning the relays on all at the same time?

Depending on the relay coils consumption and USB current output, this may bring down the USB power rail.

**Rickertsen2** · 05-25-2006, 06:45 PM

Originally Posted by LowLux

any updates?

I havn't had time to work on it since i posted the last pics. I'm going to start writing some code for it once i finish this post. I'll keep everybody informed.

Originally Posted by Chris31

Just out of interest, have you tried turning the relays on all at the same time?

Depending on the relay coils consumption and USB current output, this may bring down the USB power rail.

The usb power specifications were taken into consideration during the design. It should draw less than 500ma (the USB max) at all times even with all relays engaged, the microcontroller running under normal conditions and the LED on.

**konnichiwa** · 05-26-2006, 05:07 AM

I got this from the ExpressPCB site, i use it to do my trace sizing and its never burnt out any boards yet

Traces that carry significant current should be wider than signal traces. The table below gives rough guidelines of how wide to make a trace for a given amount of current.

0.010" 0.3 Amps
0.015" 0.4 Amps
0.020" 0.7 Amps
0.025" 1.0 Amps
0.050" 2.0 Amps
0.100" 4.0 Amps
0.150" 6.0 Amps