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Posts Tagged ‘microcontroller’

Slow Delivery – New Project

January 25, 2011 2 comments


I’m still waiting for that replacement LCD to arrive from china, i’ve ordered another from a UK seller.

I’ve not been sitting around twiddling my thumbs though; a while ago i saw a schematic for a stepper motor driver on instructables. It seemed a little over complicated to me and i figured i could easily build one using one of the PIC microcontrollers that i have, so i set about designing a cheap 3 channel stepper driver using just a 40 pin PIC and some mosfets. The advantage here is that i can give it a number of interface options such as a parallel interface, an RS232 interface or an I²C interface. There may also be options to include an LCD for status display.

The stepper driver circuit had reminded me of another one of my projects and i got the itch to start it. This is my CNC project. Its an MDF construction and the plan is that it will eventually be able to build a better version of itself. I’ve already started construction so I should soon be posting my designs.

Sunrise Word Clock – Circuit Design v1

December 24, 2010 2 comments

Ok, I’ve finally found time to make a new post about my Sunrise Word Clock. My previous attempt at making the circuit work on breadboard didn’t go so well. I assume this is because of the poor connections that the breadboard provides and could also have been because of poor layout choices. Anyway, I’ve rebuilt my prototype on strip board and i’m going to try and explain the circuit here.

The microcontrollers that i have readily available are PIC16F887. These come in a 40 pin DIP package

The interfaces i require are:

  • 2 I2C pins
  • 2 Vdd pins
  • 2 Vss pins
  • 3 programming pins
  • 1 pin for analogue to digital
  • 4 pins for button inputs
  • 6 pins for LCD interface
  • 22 pins for the Front LEDs
  • 1 PWM Power LED Channel
  • 2 Crystal Pins

Total pins required = 45… oh dear

Read more…

Getting sick of Breadboard

December 13, 2010 1 comment


My next update is taking a little longer than i had hoped. I have been building my prototype circuit on breadboard but it was behaving rather strangely. I would load my test program, all works fine then suddenly it would stop working. After unplugging things and plugging them back in again things would work again but then the next day the whole thing wouldn’t work. I finally got fed up with trying to get the breadboard circuit to work and i’ve been building my circuit on strip board (veroboard). This is a step that i was going to take eventually anyway but ideally not this soon.

The circuit is based around two pic16f887 microcontrollers. One is going to control the main clock functions and the other is going to control the lights on the front of the word clock.

Building this circuit on strip board is taking quite a while so please have patience, I hope to have a post up mid week describing the circuit.

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