The Workbench

The Workbench
Making my Dreams a Reality

Sunday, May 24, 2009

Almost a month.

Hello readers!

Been almost a month since my last post! I've been sick for a while, and school, homework... I get busy. After looking at other people's blogs, a couple of posts per month is fairly average...

So what's on the bench?

I have managed to get my RTC reading and writing. All I need now is a clock crystal and it will actually oscillate. That means it will tick over. It was much easier than I thought, I had been putting it off for a long time xD.

The wireless units are packing a sad, so I haven't gotten very far with those. I have however made the design up for the temperature transmitter. That also was easier than I thought.

For the datalogger I have designed a system for back up battery power. It's not interfaced with the PICAXE yet, but you can expect that to happen soon =). It works by having a relay witched by 12v. The N/C side of the relay is wired to the battery. So when there is 12v, (mains plug pack), the relay OPENS this side. Therefore disconnecting the battery. When the plugpack is disconnected, the relay ticks over and the unit is then powered by battery. The PICAXE will be able to sense this, and be able to switch to a lowered power state, (maybe). All of this depends on the model of unit. You know in the shops you have tons of units to choose from? This too will have many possibilities, and I am trying to be as modular as possible. That way it is just a matter of plugging in the correct modules.

I love to keep moving, so when I hit a block it is hard to stay focused. I am trying REALLY had to stay on track, so I follow a to-do list. I have to fix the wireless units, that involves getting a fresh set. I need to get a crystal for the RTC, that is now on order. I am ditching the casio interface, and will resort to a FREE serial communications program coupled with excel (not free, but most if not all schools have it...).

I think I will add an LCD module to the device, that way it is possible to see what's going on.

The aim is to stay waterproof, so lockable lunch boxes will be used. The LCD will have a clear window to look through. Even if I don't have the unit outdoors, it will still be possible to do so.

What else is on the bench? Surely more than just the datalogger! You would be right there, I am also making a two dice electronic dice with traditional display. Yup, this bad boy will have two dice. All controlled by ONE PICAXE 08M. The 08M has 4 OP pins. Three of them can be used as tri-state. I am using two tristate pins to control the dice displays, and a plain old OP pin to switch a transistor to select the dice being displayed. The wireing was easy. The code? Not so much... I am trying to find a way of having the PICAXE generate two random numbers, choose which dice number the corrosponds too, and then display that number on the dice. It will have to flash really quickly between the two dice to show two different numbers (seemingly as the same time!). This is due to Persistance of Vision, a phenomenom where the brain updates your vision slower than what is bing updated, so you see both dice at the same time.

My windmill. I have chosen a savonius design this time. Due to renovations, this one is going on the shelf for a little while. You heard right, renovations. Or house is having an overhaul! New Ensuite, new bathroom, sister gets a new room, Dad and I get a new garage! It's going to be good =). Construction commenses on the 1st of June (day after queen's birthday weekend). We have a shipping container on the front lawn to hold our stuff. The go kart, the windmill, and more have going in here.

I guess I'll make another post soon, I'm busier in the holidays normally. So I would normally make more posts then, but I forget =).