AXE091 Development Board Mod

[Hydroid]

Hi All,

Here's a quick, easy mod, that can save a lot of grief. I have the AXE091 development board, which has a single 7 segment LED on it. It is pinnned out to a header WITHOUT current limiting resistors. I also dabble in Basic Stamp and have their development board which has five 7-Seg LED's - but their board HAS resistors.

So, I figured that before I blew the display, I would add resistors. A dremel tool cutoff wheel slices the perfect slot between the connections and leaves just the right gap to solder in a surface mount resistors. While I was at it, I did the servo signal line as well (not shown in photo) since all the docs I have call for a 300 ohm resistor there too. I didn't have 300 ohm, but I did have 330 ohm. They work just fine.

They're so small that it took some time with tweezers and my magnifying headset, but it worked out great. Much less risk now of releasing the magical blue smoke that makes solid state devices work

Regards, John.

 

[BeanieBots]

An interesting dilema.
By definition, as a development board the user want's to be in full control. Having resistors already fitted takes some of that control away. The issue really comes down to what value they should be. Personally, I prefer it the way it is so that I have the option to fit my own values or have none at all if using it via an LED driver chip that outputs current rather than voltage.

Same is true for the servo output. It's very easy to wire via breadboard section to include a resistor. Not so easy to link out if one is already included.

None-the-less, a very neatly executed mod.

 

[Hydroid]

An interesting dilema.
By definition, as a development board the user want's to be in full control. Having resistors already fitted takes some of that control away. The issue really comes down to what value they should be. Personally, I prefer it the way it is so that I have the option to fit my own values or have none at all if using it via an LED driver chip that outputs current rather than voltage.

Same is true for the servo output. It's very easy to wire via breadboard section to include a resistor. Not so easy to link out if one is already included.

I see your point.

For me, being used to my basic stamp board, which has resistors fitted, it was more to make the two similar. I've gotten used to having them there. I've already forgotten twice and decided to do this before I fry the LED.

It glows an eerie shade of death if the resistors aren't there

John.