Search found 93 matches

by ljbeng
Mon Aug 22, 2005 12:52 pm
Forum: General Discussion
Topic: x10 technology
Replies: 8
Views: 2484

Re: x10 technology

Make you own power line interface and send the data however you want:<p>
Philips
by ljbeng
Fri Apr 08, 2005 1:30 pm
Forum: General Discussion
Topic: 3X4 Keypad and NTE1690 DTMF Encoder
Replies: 1
Views: 852

3X4 Keypad and NTE1690 DTMF Encoder

This chip has 4 pins labeled ROW and 4 pins labeled COLUMN each has an internal 40K pull-up resistor.<p> NTE1690 <p>The data sheet says that one row pin and one column pin must be grounded to send tone. <p>A standard 3X4 grid keypad simply shorts together one row and one column when a key is pressed...
by ljbeng
Fri Feb 25, 2005 8:31 am
Forum: General Discussion
Topic: FCC Approval
Replies: 2
Views: 969

FCC Approval

Would a consumer device that uses only 3 AAA batteries, 3 push buttons and a custom LCD require FCC approval? The microprocessor is the TI MSP430F413 and the crystal is 32,768 KHz. Thanks.
by ljbeng
Wed Feb 09, 2005 5:18 am
Forum: General Discussion
Topic: Battery check
Replies: 11
Views: 2963

Re: Battery check

The main components are (2) AA batteries operating a pic micro (16f628). I don't want an led on when the batteries are new to conserve power. I do want it to come on when the batteries get low (even though this means faster battery drain). Possibly I could pulse the led on/off to conserve power. <p>...
by ljbeng
Tue Feb 08, 2005 1:00 pm
Forum: General Discussion
Topic: Battery check
Replies: 11
Views: 2963

Battery check

I need a battery test circuit with as few components as possible. I just want to test 2AA batteries in series and turn on an led if they are < 2.5V.
by ljbeng
Tue Jan 04, 2005 5:07 am
Forum: General Discussion
Topic: Who makes the best basic compiler for Microchips Microco
Replies: 8
Views: 2946

Re: Who makes the best basic compiler for Microchips Microco

I love BASIC.<p>I used to fear C.<p>Until I tried C. If you know BASIC, you can do wonders with C. I was amazed a how similar the two languages were. I taught myself C in about a week and I haven't used BASIC or Assembly since.<p>With that said, www.ccsinfo.com makes a good C compiler for Microchip....
by ljbeng
Tue Nov 30, 2004 10:13 am
Forum: General Discussion
Topic: Digital to Resolver conversion
Replies: 1
Views: 812

Digital to Resolver conversion

I have developed and tested a new position sensor for large farm irrigation equipment that indicates the position of the equipment in degrees and sends this data to our computer main control panel. It works great and sends data to the panel using RS485 serial. <p>I have some customers who want to re...
by ljbeng
Mon Nov 15, 2004 11:34 am
Forum: General Discussion
Topic: Microphone to Microprocessor
Replies: 3
Views: 1176

Re: Microphone to Microprocessor

The micro does a lot more than just react to the sound but sound is one of the inputs I need. I want it to go to the analog input so in the future I can look at the relative sound level to do other tricks.... (it's a toy dog thing for my kid. It used to have a cabled remote control with 5 functions ...
by ljbeng
Mon Nov 15, 2004 8:33 am
Forum: General Discussion
Topic: Microphone to Microprocessor
Replies: 3
Views: 1176

Microphone to Microprocessor

At some time in history, I saw a simple electret microphone amplifier that connected direct to an analog (0-5V) input of a microprocessor. Does anyone have a link or example of this drawing? I want very simple sound activation (any sound louder than a whisper) Thanks.
by ljbeng
Mon Sep 27, 2004 11:32 am
Forum: General Discussion
Topic: MSP430F412 and 3 AA batteries
Replies: 9
Views: 2751

Re: MSP430F412 and 3 AA batteries

I got a suggestion to use a DC/DC step up converter like LM2703 or MAX1674. Anyone with any experience with these? It looks like the LM2703 will use more battery current when the processor is asleep. MAX1674 looks best but I hear bad things about supply/delivery/price.
by ljbeng
Fri Sep 24, 2004 11:19 am
Forum: General Discussion
Topic: Simple Water Detection Circuit
Replies: 10
Views: 4310

Re: Simple Water Detection Circuit

Put a 750K resistor from a microprocessor input to +5. Now put a stripped wire to the processor input and lay the other end where you want to detect water. Now put another stripped wire from ground to near the other stripped wire. This works on a pic. You should see a simple high/low when dry/wet.<p...
by ljbeng
Thu Sep 23, 2004 10:09 am
Forum: General Discussion
Topic: MSP430F412 and 3 AA batteries
Replies: 9
Views: 2751

Re: MSP430F412 and 3 AA batteries

Thanks everyone. I bought a demo board from www.softbaugh.com (BLCDA4) that I am using to do the programming. It is very similar to what our final product will look like so I can test battery life and regulators with that board. Currently, it is drawing 99uA while displaying data on the lcd. We will...
by ljbeng
Wed Sep 22, 2004 5:19 am
Forum: General Discussion
Topic: MSP430F412 and 3 AA batteries
Replies: 9
Views: 2751

Re: MSP430F412 and 3 AA batteries

I should have said 3 AAA batteries (typo in previous post) The customer wants the batteries to add weight to the device. Voltage is still the same as AA. I am planning on using a TPS76933 3.3V regulator.
by ljbeng
Tue Sep 21, 2004 7:21 am
Forum: General Discussion
Topic: MSP430F412 and 3 AA batteries
Replies: 9
Views: 2751

MSP430F412 and 3 AA batteries

I need to power a MSP430F412 project with 3AA batteries. This adds up to 4.5V and the MSP has a max of 3.6V. We want as few components on this board as possible. Would you use a regulator or 2 diodes in series to drop the voltage? This board only has a custom lcd, 4 pushbuttons and the batteries. Th...
by ljbeng
Mon Aug 30, 2004 10:03 am
Forum: General Discussion
Topic: Source for 25 Watt Amp
Replies: 5
Views: 1494

Re: Source for 25 Watt Amp

The speaker is an 8 ohm, 150Watt, Horn type speaker/driver made by Selenium (sp).