To my best of knowlege, this schematic will work, it was drawn from the breadboard circuit I built. If you detect a problem, let me know and I will fix it. Here are a few tips about building any circuit.
Check every part upon receipt.
Breadboard and test things out before grabbing the solder iron or wire wrap tool
Pay close attention to polarity LED and Tant Caps have the long lead to positive.
Print out the schematic and as you make each connection, mark it out on the printout.
The subcircuits within dotted lines are optional.
The reed relay parts are for checking the response of the sensor to 100% O2
The sensor and 10,000 K pot allow the sensor output in pure oxygen to be set in the field.
PARTS LIST FOR LEDHUD
GO ON A SHOPPING SPREE
The following is a basic parts list for the LEDHUD with suppliers. I do not stock or supply parts for resale. I am a tinkerer and am not in this for any profit...I'm not a Faringi and ignore the rules of acquisition. This does not list construction tools or test equipment. Most of that is available at any of the major suppliers listed below and at your local Radio Shack.
Any construction tool box should contain a low power soldering iron, wire wrap tool and wire, a Digital Volt Meter, alligator test leads, an IC puller, and wire. I usually buy a grab bag of LEDs and resistors instead of running out each time I need one. I buy batteries in bulk from Batteries Plus, and battery holders and snaps in bags from Radio Shack.
PARTS LIST
Red LED (LONG LEAD POSITIVE TOWARD THE STAMP)
Green LED (LONG LEAD POSITIVE TOWARD THE STAMP)
Basic Stamp BS1
LTC 1298 AD Converter (NOTCH IS BETWEEN PIN 1 AND PIN 8)
LM324 Op Amp (NOTCH IS BETWEEN PIN 1 AND PIN 14)
Breadboard & Connectors
25 pin male solder cup connector
1,000 ohm resistor (2) 1/8 watt or higher
20,000 ohm resistor (1) 1/8 watt or higher
10,000 ohm resistor (2) 1/8 watt or higher
200 ohm resistor (2) 1/8 watt or higher
10 Mf Tantalum Cap (LONG LEAD POSITIVE-VERY IMPORTANT)
THE FOLLOWING IS A LIST OF SUPPLIERS I HAVE USED
Basic Stamps
Marlin P Jones
All Electronics
Jameco
Parallax
Digi-Key
Ltc 1298 AD Converter
Digi-Key
Parallax (Complete 1298 app kit with code)
LM324 op amp
Jameco
Digi-Key
Radio Shack
All Electronics
Programing cable and parts
Made up cable with the stamp start up packages
Marlin P Jones
All Electronics
Jameco
Parallax
Make your own cable
DB 25 Male chassis mount solder tail connectors
Marlin P Jones
All Electronics
Jameco
Parallax
Radio Shack
Digi-Key
Breadboard and Jumpers
Radio Shack
Marlin P Jones
Jameco
Digi-Key
All Electronics
LED
Radio Shack
Marlin P Jones
Jameco
Digi-Key
All Electronics
Reed Relay
Marlin P Jones
All Electronics
Some Radio Shacks
10 Microfarad Tantalum Cap
Jamco
Digikey
Parallax (Complete 1298 app kit with code)
Resistors
Radio Shack
Marlin P Jones
Jameco
Digi-Key
All Electronics
Supplier Web Addresses
Parallax Basic Stamp Site
Marlin P Jones
Jameco
Digi-Key
ALL ELECTRONICS,
Bargain Hunters go look through
http://www.goldmine-elec.com
Have fun shopping, it's part of the game.
Tom
