Scaling the heights, or not…

Well I’ve made a start on re-building the scales. Things are a bit more mixed than I would like though. Firstly, a bit more dismantling revealed “The Blob”

Thing from Outer Space, innit

Thing from Outer Space, innit

Not a lot I could do with that, really. Below the LCD was the backlight. Basically, a blue LED baked into some perspex:

Cool Blue

Cool Blue

So, what am I going to do? Let’s start with the on/off switch. I found a good write up here which provides this circuit:

LatchingPushButtonHave built it on breadboard and it no worky :(.

Arse!

Arse!

I only had BC327 and BC337 to play with, not the BC547 and BC557 as shown in the diagram. Guess I need to talk to Kirchoff and Ohm to figure out what values of resistors I should be using. I’ll try that first. It’s not like their laws are complicated, is it?

The display has also progressed:

First light

First light

That’s my one remaining 4 digit, 7 segment display. All working with MAX7219 and Arduino on a breadboard.

Spaghetti Citi

Spaghetti Citi

Have started transferring that to Adafruit Perma-Proto board, using some ripped apart ribbon cable wire to make the signal connections. It’s going to fit in the case quite nicely.

Early days

Early days

Obviously, I’ve still got on/off to sort out and there’s the small matter of interpreting the load cell data. Not sure the Arduino ADC is up to it to be honest – it’s 10 bits but the 2 LSB are away with the fairies some of the time. That’ll be 8-bit then. May buy a decent 12-bit i2C ADC for more resolution. Will need to check out the load cell and the INA125P on a breadboard first though.

Still, it’s moving forwards. Nice to have something that is…

 

 

 

 

 

 

 

This entry was posted in Uncategorized. Bookmark the permalink.

Leave a Reply

Your email address will not be published. Required fields are marked *

*