K8055 and Analog Sensors

Kits PC Related Projects
1

Hello all.

I’ve just bought a K8055 interface to play with duiring the winter evenings. I have a few half formed, or possibly half baked, ideas I want to explore.

I want to explore what can be done with sensors so I started out with a couple of simple ones. I’ve got a 100k Thermistor on analog input 1 and an LDR on input 2. I’ve written some code to read and display the ports.

With the sensors conected I can see the change in voltage on both inputs with a meter when either the light level or the temperature changes. However, reading the ports with ReadAnalogChannel(1) and ReadAnalogChannel(2) gives me a reading of 130 on both channels!

I can change this to any value between 0 and 255 using RV1 & RV2 but I can’t read the data from the sensors.

I must be doing something fundamentaly wrong and I’m probably going to kick myself but I need some help please.

How can I read the sensor inputs and get the software to see the data changes as the voltage changes that I can see with a meter.

I am also thinking about trying to drive an LCD display with the card. I have one that uses the HD44780 controller. Has anyone done this and have a diagram or notes that I can look at to get me started?

Many thanks.

2

Right, I’ve got it, I’ve been to the pub and took the cct diagram with me.

Between us we decided that I needed an external +5V and to remove the SK2 jumper. For the time being I’m using the +5v supplied by input 2 and have connected my thermistor across inputs 1 & 2, this works.

All I have to do know is work out how the reading converts to degrees C.

To return input 2 to use I need to find another +5v source. I suppose I could take a lead off the +5v side of SK2 and try that or set the DAC1 output high and use that.

Isn’t beer a wonderful brain lubricant?

I’ll let you know how I get on.

3

Indeed, it is… :slight_smile:
Nice that you got it working.