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1

So the more I am working with picaxe products the more I am finding limitations to their boards...

For example: The 28 board (which I believe has become sorta the "standard" has no specific i2c output, no space for an EEPROM, the output and input pin arrangements change from one side to the other and inputs 0-7 have no ground! So here's the deal, I think I am going to design a super-board for myself and was wondering if anyone wanted to throw in their ideas as well. I will be designing around a Picaxe 40x1 as it is usally the same price as a 28x1 but with so many more in's and out's.

Here's what I have so far:

A good on/off switch

A seperate switch for just the motor driver

All outputs and all inputs are 3 pin Neg/Pos/Signal (set-up for servo connector)

Jumpers or dip-switch to switch the L293D from out 0-3 to out 0-1 and the 2 PWM outputs

Space for EEPROM(S) and seperate SCL/SDA output pins

IR input for remote control

Seperate Serial IN/Out

Screw terminals for L293D

Trimmer Pots on-board for motor trimming/ etc.

Somewhere easy to add resistors to outputs for servos

 

 

2

options

great idea. Here are some of the things I think might be useful:

 

  • Three power supplies. V1=5V for the logic circuit. V2= 5V or 6V for servos. V3=6-9V for motors because of the voltage drop from the motor driver
  • There should be jumpers or dip-switches to use only 2 or 1 powersupply.
  • Volt regulators: or at least the option to add them later. There are nice switching voltregs here (http://www.dimensionengineering.com/DE-SWADJ.htm) that are adjustable.
  • (room for) stabelizing Capacitators near the noise making outputs and near the analog inputs
  • 16Mhz resonator (because it is compatible with the servo command)
  • Jumpers or dipswitches to disconnect the I2C pull-up resistors (in case the board is used as an I2C slave)
  • a 2 pin header for an external powerswitch
  • a 2 pin header for an external reset button
  • three 2 pin headers for power leds (V1, V2 and V3)
  • pull down resistors (or trimpots) for the analog inputs
  • pull down resistors for the digital inputs
  • dip-switches to enable or disable the pull down resistors
  • onboard USB to Serial converter so you can connect using a regular USB cable.
  • Power from USB so you don’t need a battery when experimenting.
OK. Maybe all those things combined will turn your idea into a huge board, but I hope there is something usefull in my list.

 

3

some ideas:set up some of

some ideas:

set up some of the (3 pin)outputs to use a higher voltage power source.(like for servos).

Caps to smooth out power.

maybe jumpered outputs with optoisolators.

4

@ Voodoo
Hey, gimme a link for those optoisolators. --You seem to like them a lot and I know what they do, but I have never worked with them before.

5

this is the one I’ve been

this is the one I’ve been playing around with.

http://www.sparkfun.com/commerce/product_info.php?products_id=314

I grabbed a couple when I made an order a while back.

 

6

Were you going to etch them
Were you going to etch them yourself, or order them out?