Kris’s Thoughts

Projector Controller

Originally uploaded by kris_wotipka

Prototype of my Projector Controller. Based around a PICAXE 18X micro.  This is basically a macro generator.  The series of projectors I am using (Eiki, Christie, Sanyo) all use very basic ASCII text commands to control their functions.  Why make a controller you ask?  Well, the IR controller that these units come with have to be pointed directly into the front or rear of the unit.  Not good when they are suspended 20 feet in the air.

The crappy DYNEX USB to serial converter that I am using does not put out a nice clean RS232 signal. So, the SP3232 chip on the left is handling the cleanup of both the programming interface (along with the Hex Inverter on the Right) and the second output (pin 6) of the PICAXE. PIN 7 goes high to red led to signal an output. The resistor array on the bottom right is an ADC keypad simulator. (http://www.lancer3.com/ADC%20Keypad.htm).

Heathkit dev board

Originally uploaded by kris_wotipka

Here we see the Heathkit developer board. This thing is old. I think I got it at a state auction. It provides variable + and – DC voltage as well as a sine / square wave generator. It also has a small pin board which is currently holding a darlington chip array (ULN2803A) and a stepper motor.

Engine Speed Control Project

Originally uploaded by kris_wotipka

engine throttle project – looking to build a controller for my generator. Project features include speed control, startup/shutdown sequence (start, idle, run, cooldown, stop), monitor oil pressure, temp, batt voltage, etc.

new project box

Originally uploaded by kris_wotipka

Mounted the Picaxe dev board in an ArtBox along with the Max232/Hex Inverter board I built. Was running out of room on the dev board for stuff. The box closes and allows me to transport the boards when I travel.

Max232 / Hex Inverter Board

Originally uploaded by kris_wotipka

Well, I ran out of room quickly on the PICAXE dev board. So this is an outboard TTL to RS232 board. You can see some header pins in various places. I have the option to be able to switch pins 2 & 3 via some headers to create a null modem or normal pinout scheme on the DB9. I also have to option to put the hex inverter inline via headers. I left room to put another DB9 to take advantage of the other two channels in the 232 chip and the other channels in the hex inverter.

This board is used to convert the TTL levels of the PICAXE to RS232 and invert the logic if necessary. The biggest lesson learned here was not to crowd the components on the board.