In the early days of computers I recall using a device that you could do simple experiments with. It connected to the Apple II joystick port an you could measure light and other simple projects. I don't recall what it was called but I do recall wanting to learn more about electronics at the time. Today a popular controller is the BASIC Stamp by Parallax. But it's not open source and the OS is not user reprogramable. So I thought it might be a fun community project to develop a very simple device that could do simple experiments and be programmed via a serial port (it would be nice if it could be used with any terminal software).
Simple RS232 @ 2400,n,8,1
Power from the RS232 and or 9V battery
I figure the 128bytes of internal EEPROM would be enough for very small programs.
J1 thru J3 are 5 way binding posts so things like external resistors, switches, thermistors, CDS cells, 1wire devices etc could be added by just connecting the wires.
LEDs 1 & 2 would be nice if they were the huge 10mm versions.
SW1 & 2 are for simple projects
I could add an ICD / ICP connector making the firmware updatable.
You can view the schematic at.
Suggestions? Comments?