The Workbench

The Workbench
Making my Dreams a Reality

Tuesday, March 24, 2009

Temperature and Copper Forming


I have installed the temperature sensors, and have wired them to the same box. This box will contain the PICAXE and the RF transmitter. I have sensors measuring; Inside Temp, Outside Temp, Roof Cavity Temp, Exterior Wall temp (Measured from inside wall).

Go Kart

Took a LONG time to solder the wire... The cable is 8 gauge, and is made from the smaller copper fibers (like the ones you find in hook up wire). Should be a really strong connection :-). This cable is what I will use to hook to starter motor to the positive of the battery.

I have ordered the MOSFETs needed to make the switch, and I am waiting on the batteries, and the HUGE blocking diode (25ish Amps!!). To be honest, I don;t think I need one so big, but if I'm wrong, there goes $20 worth of MOSFETs...

Sunday, March 22, 2009

Been Busy Lately

Hey Guys,

I haven't made much progress on the Go Kart or the Datalogger...

Me and my sister have bought a pet rat each, and I have spent my time looking after Samantha. My friend Jack, Sarah (sister), and myself spent last weekend bulding them cages ($60 for a commercial one!). Haven't taken any pictures of them yet as I haven't got around to it just yet, but don't worry :-).

Go kart:

Tomorrow I will order 4x The needed MOSFETs. The switching power will be about 500A at 12V (6000W!!). Then I need to go to DSE and buy a meter of 8 gauge wire (1 meter Red 1 meter Black).


Have ordered a RTC from maxim, and that should arrive in the next couple of weeks. I have also started to run the wires for the temperature sensors. Will measure; Roof Cavity, Inside, Outside and Inside the wall (touching the exterior wall). I am waiting for a meating with a man by the name of Dave. He has a fisher and paykel washing machine I may be able to have. I'm hoping it is a smart drive - they make good windmills. I also want to put up a new tower for the windmill so it gets a nice strong wind. I will have to follow some plans from a man in NZ - I can weld, and I can get scrap steel. Hoping wood is cheap, need about 5m!!. I dont think I can build a new tower, dad wouldn't be too pleased, (and just quietly I can't afford it :-P).

I would say that is enough from me for now.


Dan - AKA Microman171

Saturday, March 14, 2009

The Go Kart

Me and my friend Jack are currently building a go kart.

It WAS going to be a petrol one, and I even bought the engine, but it didn't really work out... The engine was really old and damn hard to start.


I now have a starter motor from some car.

I don't know anything about it, except that it runs on 12v.

Hopefully I will be able to get a couple of crappy old batteries from the wreckers I got the motor from.

This is the schematic for the PWM motor controller:

The four MOSFETs are going to be changed into 5. May seem excessive, especially when they are rated at 169A each! But they are only little TO 220 packages, and I don't know how much power they can dissipate. They are, however, quite happy running at about 70°C.

I am getting these MASSIVELY rated MOSFETs from Ross at Bright Sparks for $4.50 each - Thanks Ross!

Jack and I have just finished putting the Battery supports on. It is long enough to hold 3 - 4 batteries | || || | <-- Like that. I welded some angle iron onto one side, and the other side alreay had a bar. I used aluminium diamond plate for the actual support, and that it supported by another angle iron bar. It is all nicely bolted down.

Will keep posting updates as they come! Should be another one either this weekend or next. Getting the accelerator pedal hooked up to the potentiometer should be a bit of a challenge...

Will put everything into nice boxes :-). Due the the fact this kart is electric, I can have reverse too! It involves a single relay...!

Wednesday, March 11, 2009

First Post

I guess this will either work or it wont...

This will be where I can put some of my thoughts up onto the web. Was looking through the family blog I set up back in 2006, didn't work out... Was cool to see what I got up to. Just deleted it actually...

Any Way...

Lately I have been working on my Bright Sparks Competition Entry; The PICAXE based data logger. Plan A was to make it interface with a graphics calculator (Casio FX 9750G PLUS). Plan B is to have it interface with a computer and have that upload inot a spreadsheet.

Windows - hate it! If I was to go with plan B I would have to spend MUCH more time on windows. As if my gaming wasn't enough. I would say that a coupla hours on windows is an eternity - but I digress.

Plan B would have MUCH more memory than Plan A.

Plan A would involve wiring the PICAXE main board, (consisting of a 28X1 chip), to a 32K EEPROM. This EEPROM would store all of the sensor's variables with their time.

Real Time Clock - AKA RTC. I need a RTC of somekind so the 28X1 doesn't have to count, (which it is CRAP at!). This RTC would be read by the 28X1 whenever serial data was sent over the wireless network, (of my smaller 08M chips with sensors).

To put it simply:
28X1 = Main Board
08M = Sensor Board

The 08M transmits data (the variable\s) the the 28X1. The 28X1 read the data and stores it into its own variable\s. Then it would read the time from the RTC. The time and the variable\s would be stored as ONE variable in the EEPROM.

When the user wants to collect the data, he\she pulls out their casio calculator and plugs it up. They flick a switch on the 28X1 box. This activates CASIO mode. When the 28X1 is in CASIO mode, it no longer listens to the sensors. It will wait until the casio begins to ask for data. The 28X1 will begin the, (possibly slow), process of transmitting the variables (with time) to the casio. The casio will store it in a statistical list.

Actually... What if I didnt store the time and data together. That would make it easier right? That was I could transmit the time into list one, and the various data into differant lists. I can tell the casio is going to have a REALLY complicated program.

This is why I have my plan B. If I can get the whole system set up for CASIO mode, maybe I can convert that to COMPUTER mode. In COMPUTER mode, the 28X1 would be plugged up to the serial cable. The computer would begin, (the most likely quick), reieving of data. The data would be stored into a table, (maybe I can write a python App to put it into the linux equivilant of excel...).

We all know that all schools have excel (schools are my target audience). So they could hook the module up to the computer and get all of the data out of the EEPROM. Excel is very capable of graphing data (into a single graph!).

Plan B Subplan B would be to have the 28X1 ALWAYS hooked up to the computer. That removes the need for; a battery for the 28X1, an EEPROM, and an RTC.

I would say that is all I can really say about my bright sparks project (also will be my science fair project).

Next post will include pictures of this thing coming together!