someguynamedross.com
Various ramblings - Electronics, radio, old computers, cars & other junk...
Electronics
Random electronics projects I've messed with over the years.
Multimeter Repair
My relatively new BK Precision multimeter got rained on, a leak in the roof on the deck soaked the table I was working on when some heavy overnight rain decided to come bucketing down.
To say it was rained on is an understatement really, it must have been placed perfectly under a torrent of water that jammed more water into the meter than there was air.
Needless to say, I was rather pissed off. I pulled the battery cover off, and a large quantity of nasty looking brown-ish water came pouring out.
I proceeded to dismantle the meter, cleaning and drying all traces of water. I put it back together with a fresh battery, flicked the range switch around, and nothing...
Shit... So I pulled it apart again to have a better look at the board. It looked fine first time around, but under closer inspection I noticed that several of the tracks leading away from the positive battery snap solder joint were corroded away down to bare fibreglass board.
I followed the trace until I found an undamaged section, scrubbed the green laquer off the trace and installed a small piece of wire in the damaged sections place (small 30 gauge wire, like they use to fix mistakes on prototypes and the like).
I plugged the battery back in, and it was working!!
The meter still seems to perform as well as it did before, hopefully it stays that way. I can only assume that the tracks were damaged due to some sort of electrolysis effect.
The meter was left in the on position and it had gone into auto-off mode, I can only assume that this was partially to blame.
The corroded tracks started from the exposed copper vias through the board, eating into the copper underneath the green laquer on the board.
Bit of a shock that it happened so quickly!!
On a side note, while cleaning the meter I found a track underneath the screen that had been cut during manufacturing. What looks like a date code possibly points out that it was built in 2008. Is mine an early model? Interesting...
Rigol DS1052E 100MHz hack/upgrade
I picked up my DS1052E not long after Rigol released a firmware update that blocked the well known hack to turn the DS1052E into a DS1102E.
A few months later I thought I'd check to see if any progress had been made, and I was in luck.
A few minutes with a USB stick, some twiddling on a keyboard and I had a 100MHz scope for the 50MHz price!
EEVBlog post showing how to do the hack here.
Link to the firmware file you need to downgrade a newer 2.05 SP2 DS1052E to 2.02 for the hack here.
Link to various firmware files (including the one above) and tools here.
There is also a firmware file to upgrade from 2.02 to 2.04SP1 in that Zip file.
I'm unsure whether you can safely upgrade back to 2.05SP2 after the hack. 2.04SP1 seems to be fine, and various forum posts mention there are bugs in the lastest version.
As with any firmware update or mod like this, you run the very real risk of bricking your scope if you don't follow the instructions to the letter. Be warned!!
ArduinoISP adapter
This adapter is based off of the ArduinoISP circuit from the Arduino website.
I managed to cram the circuit onto a fairly small piece of veroboard by hiding the crystal capacitors inside the socket along with some of the links to get power to both sides of the chip being programed
The circuit performed flawlessly. After burning the bootloader I dropped the freshly programed chip into the socket on my Freeduino, programed it with the blink sketch and was greeted with a blinking LED.
Now to get stuck into building the circuit I plan to use this chip in...
Gameboy PLCC EEPROM Cartridge
Some pictures of a failed project, never got it working properly and lost interest in it.
I removed the standard ROM on a Gameboy cartridge and soldered a bunch of wires in its place. I then wired in a PLCC socket with the intention of burning ROM's into a PLCC EEPROM, but the games never got any further than the Gameboy boot logo (which is used as a form of copy protection).
I still have the cartridge in with my Gameboy collection, so I might have a crack ay making it work one day.
PLCC adapter
I ordered a set of DIP-PLCC adapters off eBay so I could program a chip to test the gameboy cartridge above (my EEPROM burner has a 40pin ZIF DIP socket), but there were delays in the postage.
I was sick of waiting so thought I'd have a crack at making my own.
I drilled out the centre of an atmel MCU, made sure the drillbit broke all the connections, and started to wire up a PLCC socket I salvaged off an older PC motherboard.
Got most of the way around the chip, but I managed to wrap the soldering iron cord around the drill vice I was using to hold the chip steady, and it fell from the bench onto the ground.
The PLCC socket got a crack in it, and rather than admit the last hour of work had been wasted I finished off the wiring and tried to glue and melt the socket back together.
Of course the socket disintergrated as soon as I pressed a chip in to it...
Wireless Hori EX2 Arcade Stick Mod
I picked up a Hori EX2 arcade stick to play fighting games on my Xbox 360 a few years ago. Great unit, though it always bugged me that it was USB and not wireless.
I finally decided to investigate converting my arcade controller to wireless after having owned it for a few months.
After some googling, I found out that a few people had managed to convert the EX2 (and similar arcade controllers) to wireless by gutting the arcade controller and cramming the board out of a regular Xbox 360 wireless controller into it.
These controllers aren't exactly what most people would call throw away items at around $70 each, and it would be fairly easy to make a mistake turning both into paper weights.
It seemed like a fairly simple process, and for the bulk of the wiring it was. Unforunately some of the digital buttons on the Hori controller are mapped to the analogue triggers on the wireless controller.
I had a play with rigging up some circuitry to make the digital button presses register as a voltage level on the controller, but managed to damage some traces on the multi-layer board when desoldering the trigger pots...
I thought I'd have to start again on new board, but luckily all of the fighting games I had at the time had the ability to map buttons, and I was able to use different buttons in their place.
Did it end up working? Yep! No more tangled cords while handing controllers around and one less cable to trip over. Every game I've tried with the controller so far has had the ability to map buttons, so my stuffup with the triggers didn't turn out to be a complete disaster, it's just a minor annoyance as I have to map the buttons before we can play.
Below are some pictures on the wiring, and some pictures of the finished controller.
PIC based thermometer
I stumbled on to this website a while back, and thought it would be a nice basic project to get into PIC development.
I had planned to try program my own version, but this one worked very well and looked good so it stayed as is.
The battery was re-purposed from another Nokia phone (which I kept so I could charge the battery), and powered the thermometer for a good 2-3 months between charges.
It lasted for a couple of years but sadly it stopped working out of the blue, I think the LCD died as there was something growing/forming between the glass.
