Organize and Share your Electronics the way you want. Sign-Up for a free account now. It takes only 30 seconds!

Count Accumulator for Radiation Levels (CARL)

Count Accumulator for Radiation Levels (CARL)

An add-on numerical counter that plugs into the headphone jack of 1960s vintage geiger counters such as the Victoreen CDV700 and CDV700-6B. Also works with the Lionel ENI LENi counters or any other geiger counter having a headphone output pulse greater than -5V.
The main parts of the CARL circuit include an input pulse shaper, an audio click sounder, a microcontroller that runs the counter program, and a liquid crystal display module (LCD).?
DC power at approximately 5.7V is used to power the circuit. The 1N4001 diode drops that to around 5V. The 5.7V shown on the schematic comes from the low voltage dropout regulator circuit in the companion “Hot Rod CDV700” modification circuitry. The microcontroller and LCD module are capable of operating anyhere in the 3-6V range, 5 Volts is optimal.?

The CDV700 geiger counter produces a negative going pulse on the phone output with about a -20V swing. The pulse is limited, then fed into the LMC555N CMOS timer IC, which lengthens and squares the pulse. The 5V zener diode limiter prevents the negative going headphone click signal from going below 0V (5V less than +5V), this prevents the CMOS timer input from latching up or being damaged. The squared pulse on pin 3 of the 555 is inverted by the upper 2N3904 transistor to create a low-active pulse, that signal goes to the microcontroller interrupt pin for counting purposes. The pulse is also inverted by the lower 2N3904 transistor, that signal is used to drive the mini speaker for the clicking sound. The mini speaker volume is selected by the soft/off/loud switch and two resistors.?

One could easily extend the interrupt pulse signal to a ttl-compatible input on a computer. It should be possible to feed the signal to an input on a PC parallel port, for example.

Visit Here for more.







 

More Articles to Read

Peeqo is a desktop bot that communicates through GIFs
Peeqo is a desktop bot that communicates through GIFs
Using a Programmable Input Multiplier to Minimize Integer Boundary Spurs
Using a Programmable Input Multiplier to Minimize Integer Boundary Spurs
Serial seven segment LED display shield
Serial seven segment LED display shield
G-code controlled drawing plotter
G-code controlled drawing plotter
An Arduino round word clock
An Arduino round word clock
The Sandwich-o-Matic will make your lunch automatically
The Sandwich-o-Matic will make your lunch automatically
Scalar Network Analyser Jr
Scalar Network Analyser Jr
An Arduino-controlled automated whiskey distillery
An Arduino-controlled automated whiskey distillery
The Rex800 looks like a dinosaur Terminator
The Rex800 looks like a dinosaur Terminator
Home Environment Monitor
Home Environment Monitor
Understanding the Operation of the Frequency Synthesizer in Maxim’s RF Transceivers
Understanding the Operation of the Frequency Synthesizer in Maxim’s RF Transceivers
App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor
App note: EPIC: Electro-Pyrotechnic Initiator Chip Resistor
Noisy ESP8266
Noisy ESP8266
App note: Noise analysis for high-speed op amps
App note: Noise analysis for high-speed op amps
Skill Sunday: Arrays
Skill Sunday: Arrays
App note: Infrared remote control implementation with MSP430FR4xx
App note: Infrared remote control implementation with MSP430FR4xx
Gesture Controlled Smart Home
Gesture Controlled Smart Home
Design for a Wideband, Differential Transimpedance DAC Output
Design for a Wideband, Differential Transimpedance DAC Output
Wrist thrusters let you fly through the water effortlessly
Wrist thrusters let you fly through the water effortlessly
Bertan/Spellman 225-20R HV power supply teardown
Bertan/Spellman 225-20R HV power supply teardown

Top


Shares