Hi All -
I'm sure everyone is familiar with the typical 5x7 dotmatrix LED displays. Particularly the ones that snap together so you can build a larger display ...
I want something just like that, but with a much smaller pitch or size. All the ones I've seen look like they use the equivalent...
Hi All -
I have a 10kW diesel generator here that feeds into a Xantrex/Trace inverter for power backup at the house. Unfortunately, the generator is fairly simplistic in that it only has a few (lousy) analogue gauges on it, with no protection/detection circuitry at all.
I would like to build...
I'm missing something fundamental here ... I have a typical voltage divider circuit, consisting of two resistors, a 39k and a 22k, plus a 10k pot to adjust things. The 39k is the top leg for input, the 22k and 10k pot are the bottom leg to GND. When adjusted for about 25k, it will divide 12V...
Hi All -
I'm thinking about designing and building a remote car starter. I know that there are lots of different ones already out there in the market, but where's the fun and learning in going off-the-shelf ?
Most starters use relays, either external triggered from a smaller one inside, or...
Hi -
My library of test equipment is starting to grow, slowly. Odd how it does that :) Several of them have gpib interfaces, like the digital scope and so on.
What do you use as your PC control software ? Labview ? Unfortunately, that's awfully expensive for a home lab - what else is there...
Hi All -
I'm looking for a room occupancy sensor. Needs to be small, and able to detect someone entering a room from a good 8m-10m away. This is for simple interfacing to a microcontroller.
Siemens makes a really nice little microwave sensor, the KMY24, but it doesn't appear to be available...
Well dang it. Didn't quite read the datasheet closely enough.
I have a car datalogger design that uses the DG333A quad 2>1 mux switch to multiplex the 16 input signals to 8 opamps for signal scaling for the ADC. The part I didn't notice was the voltage limitation on the signal inputs ...
I'm seeing some strange results from an air-core transformer - basically two coils of 30ga wire. Perhaps someone can shed some light ?
Primary coil is 170 turns of 30ga wire that was wound on a 2" dowel. The secondary is 100 turns the same way. The two coils are sitting on the desk, the...
Hi All -
Can anyone recommend a source for a windshield rain sensor ? Preferably one that doesn't require a 10,000 unit purchase :)
I'll take pretty much any technology, resistance, refraction, whatever. I just want to retrofit an auto-trigger for the wipers on our cars ... Interfacing to a...
Hi All -
I have several UPS's here that use the typical 12V 18AH sealed lead-acid batteries. A couple of these have died, in that they light up the "replace battery" LED or similar means.
I've pulled the batteries out, but I'm sure that they're not ALL bad - there's about 10 of...
Hi -
Can someone recommend a good pci GPIB card, and preferably a source too ? What little digging I've done shows them to be ludicrously priced :(
This is to use LabView to interface to an HP oscilloscope with a GPIB interface.
Thanks -
Dean.
Hi -
I'm in the final stages of the Datalogger design for cars. I had originally wanted to include clamping diodes on all the analog inputs, using the PACDN017 smd array from CalMicro.
http://www.calmicro.com/products/data/pdf/pac_dn017.pdf
After much pushing and shoving in the PCB layout...
I know it's kind of off-topic, but I would think that this would be a good group to ask this question of.
What is a good source for project enclosures ? One that can provide a good idea/drawing/definition of the boxes, so I can design the pcb and mounting holes appropriately. Not Rat-Shack...
Hi All -
Please take a quick look at http://www.eng-tips.com/gthreadminder.cfm/lev2/6/lev3/35/pid/108 if you get a chance ...
I'm building a datalogger for in-car use, and am stuck at the A/D input design stage. I don't know analog/opamps :(
Basically, I need an opamp buffer for each input...
