Archive for the ‘Electronics’ Category

usbSimStepper PCBs have arrived

Tuesday, October 27th, 2009

I designed a dual stepper motor controller that interfaces to a computer via USB for use in my flight simulator. These boards will drive various instruments, such as my airspeed indicator. This is the first time I have used Seeed Studio for PCBs and I am very please so far with the end result. The total cost was right at $50 for 11 of these boards which measure about 3 inches square.

usbSimStepper01 usbSimStepper02 usbSimStepper03

 

Here is one of the boards mostly populated with parts and installed on my home made airspeed indicator.

ASI_pcb01

 

Update: There were a couple of minor errors on the board layout. Here is an updated schematic.

MJoy16 key matrix board

Wednesday, October 14th, 2009

I built the MJoy16 controller quite some time ago and finally got around to making the key matrix board that allows easy input hookup. This board is double sided and a lot more tedious to drill and populate so I had been putting it off. I once again used the toner transfer method with good results.

Cockpit 003 Cockpit 005

Cockpit 008 Cockpit 010

It took about 10 minutes to get the two papers aligned properly and then it was pretty short work to etch. A lot of soldering and drilling later and here it is:

Projects 027 Projects 028

CNC router

Tuesday, October 6th, 2009

You have to use your imagination, but this is the start of a CNC router.

Projects 004

We have a 2’x4′ sheet of 3/4″ MDF, 1/8″ aluminum angle (3/4″ and 11/4“), 5/16-18×3/4″ bolts, 1/4-20×2” bolts, 5/16-18 tap and drill bit and two boxes of nuts for the bolts.

If you aren’t familiar with CNC routers then check out this Youtube search for some videos. The wife approval factor for this project is about -1000 so job number one will have to be something really nice for her. =)

JVC stereo repair – Part 1

Wednesday, June 3rd, 2009

I received a nice little JVC stereo (Model CA-HXZ3) that someone had left behind as trash in an apartment that my parents manage. It has a 3 CD changer, tape deck, AM/FM stereo and an auxiliary input. One of the buttons on the front hints at CD recording capability. With all this geeky goodness I just had to have it. =)

When plugged in the unit immediately powers on and goes through what looks like a normal startup routine with a lot of flashing lights and beeps. Unfortunately the only sound it made was the beeps, nothing came from the main speaker outputs. I also noticed that the power button and the CD eject buttons did not seem to do anything.

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I finally took the time to tear into it this weekend and took some pictures along the way.

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Here we have a view of each side of the unit as well as the front panel by itself in the picture on the right.

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There are boards surrounding a massive transformer and a large aluminum heat sink, both cooled by a fan in the rear. I checked all of the fuses on the power board and they tested good. There were no obvious trouble signs until I removed the large board on top.

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That power amp IC on the left is supposed to be connected to the pins in the picture on the right. The top board lifted right off with no effort so all of those pins had been knocked loose. This thing appears to have been dropped. Hard!

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By this time I gave in to the persistent “Daddy, up!” coming from Maddox and let him play on the workbench for a while. An attempt to re solder the pins led only to frustration. There is not enough room to do a good soldering job so I gave up. Luckily this is a common part and $10 via PayPal later I have one on the way from an eBay store. With that part ordered I continued to check the rest of the system for obvious damage.

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The break on the left was readily apparent and you can just make out the crack by the middle screw in the pic on the right. These two tabs house the unresponsive power and CD eject buttons.

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I removed this board from the front panel in preparation for repair. A test fit showed an easily glueable clean break. Repairing the traces will be easy but time consuming. I think my first attempt will be to clean the copper on either side of the crack and attempt a short bridge. If that doesn’t work out I will run small diameter wire from the nearest pads.

This concludes part 1. I have glued the two tabs back in place and am waiting on the replacement IC. While I am waiting I will work on getting the cracked traces repaired.

Update

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I cleaned up the broken trace ends with the point of a small round needle file and then with much squinting and soldering managed to repair all the traces on both broken pieces. If my repairs survive reassembly of the unit then I am in good shape. The closeup picture is kind of a mess, I was experimenting with the macro mode of my camera. It is the best closeup shot I could get of the tiny traces.