Tech Forum Questions

Regarding low-power remotes, check out Linx Technologies https://www.linxtechnologies.com/en/products/remotes and https://www.linxtechnologies.com/en/products/modules

They provide receivers and keyfob-type transmitters.

After reading the question I downloaded the manuals for the two cameras in question. The FinePix 2650 manual shows it capable of using 16 to 128 megabyte memory cards.  I'm afraid 8 Gigs is more than a little out of that range. The information is not easy to find in the manual.  See page 117.

The FinePix A210 is a little more capable, but not much. On page 79 of the manual for it, the usable memory capacity is listed as 16 to 256 megs.

I have a FinePix AX200 coincidentally with an 8 Gig Micro SDHC card and the adapter that you describe. It works fine. The manual lists number of exposures for cards up to 8 Gig capacity.

This doesn't help you but it does answer your question.

The simple answer is that the memory card you are trying to use is too big for the camera[s]. I looked in the manuals available online — the max size allowed is 128 MB for the 2650, and 256 MB for the A210.

Neither camera can handle the 1 GB you're trying to use. You need to find smaller capacity microSD cards. You might try to only format 128 MB [or 256 MB] and see if that works [not sure if you can do that with XD or SD memory cards].

You have two problems. The first is SD and XD cards are not interchangeable.

Problem number 2 is the only compatible cards for your cameras per the user manuals are as follows:
 

FinePix2650
DPC-16 (16 MB)
DPC-64 (64 MB)
DPC-32 (32 MB)
DPC-128 (128 MB)
 

FinePixA210
DPC-16 (16 MB)
DPC-32 (32 MB)
DPC-64 (64 MB)
DPC-128 (128 MB)
DPC-256 (256 MB)
 

So, your SD card and adapter will not work, and your cameras will not accept a 1 GB card.

The cone shaped step drills work very well for round holes in control panels. If you use a drill press it is very easy to chamfer (debur) both sides of the hole using the start of the next step. You can actually drill it half way from each side if the panel is thicker than the step on the drill.

If you want square or rectangular hole; start with the step drill then use a “nibbler” for the desired shape. Home Depot has the Klein #70611B for about $23. There are several other brands available, including heavy duty and power operated nibblers.

A one-inch round hole can be neatly cut with a step-drill.  Many come in sizes that include 1".

Also a chassis punch can be used, although the punches are more expensive. An inexpensive kit of chassis-type punches can be found at Harbor Freight Tools.

Square holes can be cut by drilling inside the corners with a small drill, then cutting between the holes with an emery wheel on a hand rotary tool, such as a Dremel. A file smooths out the cuts. They can also be cut with a "nibbler" if the gauge of the material is thin enough. Nibblers are available from many electronics supply houses that stock tools. RadioShack used to handle them, although I don't know if they still do.

Go to Greenlee punch and you will find your answer. They have been around a long time, but their punches are rather pricey.

While it's virtually impossible to declare a "best" way to do any number of things, I'll share a couple of my favorites.

For cutting round holes in thin materials, it's hard to beat a step drill bit. These are cone shaped cutters that fit in an ordinary drill or drill press and do a great job of cutting or enlarging holes up to about 1.5 inches without mangling the material.

For square holes, I often use a nibbler tool, following up with a file to clean and square up the cut. With a bit of practice you can use the nibbler to cut all sorts of shapes.

The best way to cut a one-inch hole in plastic or metal boxes is to use a chassis punch. Greenlee makes such punches. A one-inch punch is available from Grainger (see www.grainger.com/Grainger/GREENLEE-Round-Knockout-Punch-4A738?Pid=search) as well as many electrical distributors.

Problem is that they're expensive because they're meant for cutting through fairly thick steel. The 1" device from Grainger sells for about $87.

Best bet is to look on eBay for an antique radio chassis punch. At this writing, I found a 1-inch punch offered for under $10 (plus shipping).

I would suggest you try using an instrumentation amplifier designed for Wheatstone bridge application. I recommend the INA 125. I would also recommend the TLC2543 12-bit ADC such as used with a Stamp based logger in the following link: [url=http://emesystems.com/OL2tlc2543.htm]http://emesystems.com/OL2tlc2543.htm[/url]

Good luck with your project.

The SDX01G2’s datasheet shows the specs to be rather narrow.

Consider the Freescale MPXV5004 or similar. It’s range (in and out) is far wider than the SensorTechnics model. The 5004 was used in my CPAP project simply because it was a pull from an old CPAP machine.

An audio amplifier with a graphic equalizer doesn't require a DSP or FPGA. Quickfilter Technologies (www.quickfiltertech.com) sells a variety of chips aimed specifically at audio applications. The company also has development kits and a neat GUI. No programming needed. A USB cable provides a link between a development board and a PC used to set parameters.

The Quickfilter QF3DFX chip includes a 10-band parametric equalizer and an eight-band graphic equalizer. Cypress Semiconductor's Programmable System on a Chip (PSoC) families (www.cypress.com) include filter blocks, and a graphical drag-and-drop GUI makes it easy to configure a system. These chips include ADCs and DACs, so I bet Monito could create what he wants with only a PSoC chip and a couple of audio amplifier ICs. Find a useful app note at www.cypress.com/?docID=21352, and info about a 10-band graphic equalizer at www.cypress.com/?rID=43672.

If you're generally new to audio processing, I would stick with analog for a while. It's not as cool or widely configurable as a DSP, but it usually does a pretty good job when done right. For your project, you'll probably want:

1. Input gain
2. Three-band or more *parametric* EQ
3. Output gain
4. Power amp

I included two gain stages so that the EQ's working level can be adjusted independently of both the input and output levels. This allows you to overpower the analog noise in that stage without fear of clipping and still get the output level that you want. (Professional analog mixing consoles are basically that on steroids.) The gain stages are the easiest parts of the circuit: Use a dual-gang linear potentiometer (for stereo, single-gang for mono) with an extra resistor between the center-tap and ground. This loading resistor should be roughly 10% to 15% of the pot's resistance, and makes a better audio taper than most audio pots.

The power amp can be a single IC for small speakers or headphones. They're sometimes called power op-amps. The EQ is a little different than I think you had in mind. I think you're imagining a many-band *graphic* EQ, which is easier to understand at first glance, but I think a more useful tool for you would be a *parametric* EQ. Parametric means that you can adjust the frequency of each band, as well as the gain. For example, if you have a problem at, say, 3 kHz, and you have a graphic EQ with adjacent bands at 2.5 kHz and 3.5 kHz, it's going to be hard to adjust that satisfactorily. (This is why professional graphic EQ's have up to 31 bands. Even so, they still don't work well for everything.) With a parametric EQ, you could adjust a frequency knob to put one band exactly where you need it for each problem area. A semi-parametric EQ is easier to build than a full-parametric, and just has the two knobs per band — frequency and gain. A full-parametric EQ has a third knob that adjusts the width of each band. Despite missing a knob though, the semi-parametric version is usually sufficient because it automatically adjusts the bandwidth as a function of gain. Large gain adjustments typically make a narrow spike or notch, while smaller adjustments make a wide hill or valley.

This website (www.sound.au.com) is a great resource for analog audio projects. It has circuits for almost anything you might want to do to your sound, with schematics, detailed descriptions, and usually a PCB for purchase. One minor sticking point for you might be that these circuits are designed for ±15V supplies (30V total, with signals referenced to a center-tap). If all you have is 5V, you might be able to make a switching power supply that provides that, or you might be able to adapt the circuits to run on 5V with a higher noise floor. (Actually, the noise level stays the same, but you're using a smaller signal.)