It has taken almost 2 years but I finally did a local test on 30 Meters of the modified combo-star radio with a STM32F4 based digital codec board running the last port I could find of Codec2. There is still a lot of work to be done packaging, winding the rest of the filters, and completion of the high power sections. Must of the time was spent on independent projects and assembly of the combo-star was quite a undertaking. Although a hacked combo-star which I'm sure most of them are in the end given the home brew nature, I've got something now I can work with that is all integrated. Eventually I'll even have it in a ready to go box.
If you have trouble getting KICAD to build and haven't checked out homebrew you might want to check it out. I try to keep a current tap for KICAD.
To install first install homebrew if you haven't already:
ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"
Then tap the KICAD homebrew script to build.
brew tap shaneburrell/homebrew-kicad brew install kicad
To update/upgrade to the latest KICAD as often as you like.
brew update brew upgrade
I found it difficult to find a current build of KICAD for OSX. Below is a build that works with current OSX. Just unzip into Applications and start KICAD. If there is interest I may do more frequent builds.
I've been working on several stepper controller boards for other projects and I needed something small to do testing. The MendelMax 1.5 was a good option so I've started construction. These take a considerable amount of time to source all the parts and I purchased the majority from McMasterCarr and misumi. Both have excellent service, website, and very fast shipping.
I've been working on a XMOS CNC controller board and in the process came up with two prototype designs using two different Texas Instruments stepper driver IC's. The DRV8818 and the DRV8824. Both of these ended up being able to control the NEMA 17 steppers for RepRap and the NEMA 23 for my small CNC router .
I purchased a HP 5328a counter off ebay for a decent price. It arrived a few days later and I'd say cosmetically its a 9.9/10. After putting it on the bench and turning on the unit I released it didn't have the oven based oscillator. It did have channel C option and GPIB interface. After checking channel A I was really glad to see that things were working correctly. I moved over to test channel C. All was well I thought until I noticed that the connector on channel C seems to work intermittanly. After pulling the cover off I was pleased to see the unit was very clean inside. I removed the channel C card by taking a single screw out from the rear to remove the top cover. Removing the BNC was just a simple process of removing the nut. After taking the connector apart it was tarnished quite a bit. Some cleaning and I did apply a bit of pressure. After assembly the C channel was working perfectly.
After a lengthy stretch of research on the EL 512x256 Planar display I finally gave up trying to get a datasheet for it. If you happen to have a datasheet I'd love to get a copy. Planar didn't have one or so I'm told by there rep. After a bit of reverse engineering I was able to figure out the output to the display. I prototyped it on a large FPGA dev board but then wondered if it would be possible to find a usable LCD to fit the frame and to use something a bit more practical to do the conversion. I have gotten a few responses back from other 8935 owners that they might be interested in a conversion kit of sorts based on what I have done so far. I also wonder if the E8285A has the same display. If somebody has a E8285A I'd like to know if it has the same display because that might make it worth putting together a kit. For now I just seem to take a step further and further towards a complete solution each time I power up my 8935 and struggle to tell what input is in the lower part of my screen.
Here is a photo in case you have something similar. (Note the pilot production tag)
I have a HP 8935 E6380A service monitor that had some pretty severe screen burn. After looking around for a replacement I wanted to see how hard it would be to adapt a current LCD to the 8935. Suprisingly it was fairly easy. I had a 10.5 inch display and after probing around a bit to see what signals/power were on the A1A1 connector (400 i think) I started playing with a FPGA dev board to convert signals to something I could see on the screen. It works but doesn't fill the entire screen and its not the right size hardware. Now that I have a PLAN B and I've found a 6.5"ish lcd I can readily buy cheap, I'll troll along with the burnt display till it fails or I can't stand it anymore. I'm hoping there is a lot of interest in this to other 8935 owners and its something I can justify doing in the near future.
Some things I played with while I had the 8935 apart and the 10.5" connected:
- Inversion to have some way of preventing screen burn.
- Adding some color (Changed boarder color, changed color of spectrum analyzer portions of the screen) This isn't something that can be done everywhere. If its simply which pixels get what color it's trivial.
- Added text to the parts of the screen not used going from 512x256 to 640x480. Could add ADC to show voltages etc as extra info.
-Centered screen and added border.
I've be looking at several platforms to do DSP work in relation to a SDR and digital modems. I have a xmos demo board and some AVR32 items laying around which I needed nice DAC/ADC to interface with. The TLV320AIC23 is a nice inexpensive codec. I built a small prototype board to use the chip in development products and later I'll turn this into a module that can just be plugged in to various projects. This board can be used with a small MCU 16-32 bit to do APRS, GSMK (DSTAR), P25 and various other digital demod/mod. The board breaks of all of the TLV320 channels for both input and output.