Sorry its taken so long to post an update. I’m very busy at the moment with my PhD and I’m about to move house again.
Although I do have a couple of updates to post, I simply don’t have the time to write any detailed posts, but heres an outline of things to come:
I’ve decided to scrap the current word clock circuit. The I²C communications to the real time clock (RTC) only seem to work provided I don’t add any other functions to the microcontroller and I have a feeling that when it comes to getting the master/slave protocol to work with the other microcontroller, I’ll have even more trouble. I’ve decided to redesign the circuit, based around 64 pin surface mount PIC with a built in RTC. This will vastly simplify the design, although it does mean learning surface mount soldering.
In addition, I’ve got all the parts for my CNC z-axis (stepper motors, linear bearings etc), I just have to build it. I’ve also designed and built the stepper motor driver. I just need to find time to test this and blog about it. I’ll try and post a video of the motors moving when its done.
I’ve not forgotten about this blog, or my projects, I just need a few spare days to catch up on my to do list.
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.
Its been a busy holiday season. I Have been working on the wordclock but I accidentally connected the power in reverse and I seem to have damaged it. I’m waiting for a replacement to arrive from china so will post an update as soon as I get it working.
I’m not starting any of the other project stages until i’ve got the LCD working as I plan on using the LCD for diagnostics. I’ll try and work fast and do a bit of catch up once it arrives though. I don’t like being behind schedule.
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
I’ve finished my LED torch conversion. I did this a while ago but forgot to post details of it here.
Previously i had fixed the LED into the body of the torch with a heatsink. Since this is a wide angle torch, i need to mount a lens on it in order to focus the light beam. I bought a 15° lens and holder and tried to figure out a way to mount it. Originally i was going to make a frame for it either from an aluminium disk or from a pliable material such as sugru. In the end i discovered a much simpler option:
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.
My next project is a word clock inspired by drj113′s instructible on making a word clock.
My design differs from drj113′s original considerably
- Rearranged lettering on the front, giving am and pm yet maintaining a compact design
- Dimmable LED channels so that i can create smooth time transitions
- Light sensor so that brightness can be adjusted according to ambient light
- Superbright power LEDs on the back so that the clock can be used for dawn simulation.
I’ve also decided the frame of the clock will be aluminium, touching this aluminium should toggle the power LEDs on and off (with smooth transition).