Reconn's World Forum - E-mail Bag heres where I answer emails, for people (hopefully) to glean useful info http://www.reconnsworld.com/forum/list.php?37 Wed, 08 Sep 2010 23:39:10 -0700 Phorum 5.2.9a http://www.reconnsworld.com/forum/read.php?37,514,514#msg-514 Pressure Switch info (no replies) http://www.reconnsworld.com/forum/read.php?37,514,514#msg-514
(Please reply to: phillipv at nb.sympatico.ca)

I need to identify some sort of pressure sensor(s) with which to be placed at specific anatomical read-points along the Exo-frame:

1. Inner wrist for biceps contraction
2. Outer wrist for triceps contraction
3. Mid-biceps for shoulder raise
4. Just above elbow for rear shoulder raise
5. Upper knee for hip raise
6. Rear lower-leg for hip swing back

Need to be able to set a threshold for the sensors for each position’s EoCL (Edge of comfort level). If the threshold is not triggered, the joint remains un-actuated and under the pilot’s power. Or perhaps some variant of this method that proportionately increases the actuator power with the amount of force registered by the sensor. This selective passivity will allow for a greater amount of power conservation and employ more natural stored energy release for things like the Contra-Postal walk that kind of feeds itself energy via the spinal torsions, arm swing and hip swing.

Phillip

Please reply to: phillipv at nb.sympatico.ca]]> guest E-mail Bag Sun, 07 Dec 2008 16:55:03 -0800 http://www.reconnsworld.com/forum/read.php?37,512,512#msg-512 HELP ME PLSSSS....... (no replies) http://www.reconnsworld.com/forum/read.php?37,512,512#msg-512
can you give me a schematic diagram for a transistor based power supply AC to DC

output voltage:

2.5
5.5
8
10
12

thx...i need di as soon as possible...

email me at thugsterz_15@yahoo.com]]> guest E-mail Bag Tue, 19 Aug 2008 05:46:44 -0700 http://www.reconnsworld.com/forum/read.php?37,453,453#msg-453 ic preamp circuit & ipod (no replies) http://www.reconnsworld.com/forum/read.php?37,453,453#msg-453 -----------------
from ehiunno
Quote

I see the preamp is labeled for use with an electret microphone, but the application im working on requires the amplication of a low-level source(namely, an ipod) a small amount as the headphone out doesnt put out at line-level. Could i use this pre-amp in this application?

It aslo seems to me that the circuit might create a high pass-filter with a cutoff frequency well above where i would want it (created by C1 and R2) but i may be missing something or doing incorrect math as i couldnt imagine why you would want to filter out such high fequencies for a mic. Do you have the theoretical cutoffs of any of the filters in the preamp? I need something that will amplify the entire audio spectrum.

thanks a lot,
Brielin
---------------------
my response:
Quote

hey, sorry for the delay in getting back to you.

well, firstly the forum you emailed me through is deprecated (i need to take it down and fwd. all traffic to the new forum at [www.reconnsworld.com])

looking at the circuit, I'm not sure which section you think will create a high-pass filter.. (r1 & c1? r5 & c2?)

meanwhile this schematic looks very similar to a reference audio amplifier design that national semiconductor has on their website:
[webench.national.com]

so i imagine it works well. the main difference seems to be the r1 supplying voltage to the electret microphone, which in your case you don't need. in your case you would need to remove r1 and feed directly into the pin on c1.

wikipedia (http://en.wikipedia.org/wiki/Line_level) has line voltage at about 1.228vrms which would be 1.228v*(2*sqrt(2)) = 3.47v peak-to-peak
audio electronics really isn't my thing, and I can't seem to find a definitive source about 'what voltage does the ipod run the headphones', is it larger/smaller than 3.47?

meanwhile, if you're interested in a circuit that should definitely meet your specs you should check out national semi's website. they have a tool called 'my webench' which allows you to design circuits, on the website, and simulate them to make sure they operate to your spec.

check it out at
[www.national.com]

i followed the 'audio' link under the 'design' section. meanwhile they do have samples available for some of their chips, so that may help your project out.

let me know if that works for you -- also i'd appreciate if you gave me your opinion of the new forum vs. old forum

thanks,
andrew
]]> andrew E-mail Bag Tue, 15 Aug 2006 17:59:45 -0700