Hi all,

I am trying to put together this circuit from a schematic. It's a call detection circuit with an induction coil that senses the fluxuations in the EM field around a cell phone when it's receiving a phone call.

I looked at the schematic, and I *sortof* understand what's going on: RF coil passes a small amount of voltage (?) into the circuit, where it is boosted enough to pulse an LED. Eventually, I want to take this pulse into a Zigby...

Here is the schematic:

and here is what I have put together...

Any suggestions as to why this may not be working would be SO SO SOOOOOOOOOOOO appreciated!!!

<3 bree

 

Parts:
R1—————————————————100K 1/4W resistor
R2—————————————————3K9 1/4W resistor
R3—————————————————1M 1/4W resistor
C1,C2———————————————–100nF 63V polyester capacitor
C3—————————————————220uF 25V electrolytic capacitor
D1—————————————————LED 10mm ultra bright
D2—————————————————1N5819 40V 1A schottky barrier diode
Q1—————————————————BC547 45V 100mA NPN transistor
IC1—————————————————7555 CMOS timer IC
L1—————————————————-Coil sensor
B1—————————————————-1.5V battery
When a cell phone ringing, the signal detected by the sensor coil is amplified by transistor Q1 and drives the monostable input pin of 555 timer IC. The IC’s output is doubled by C2 and D2 in order to drive the ultra high LED at a suitable peak voltage. The current consumption on standby mode is less than 200uA. L1 can be made by winding 150 to 150 turn of 0.2mm, enameled wire on a 5 cm diameter former. Remove it from the former and wind with insulting tape. It can be also replace with a commercial 10mH miniature inductor, but with lower sensitivity. Use CMOS IC timer, only these device can safely operate at 1.5V supply or less.

What is the part number of the 555 timer IC that you are using?
What is the Vf and current of the LED?
Did you substitute any parts?

Your breadboard is quite spaghetti-like. You need to clean it up.

 

You also need to shorten wires dramatically. You have a situation similar to this thread...

http://forum.allaboutcircuits.com/showthread.php?t=52692

 

Thanks for the tips. I rely too heavily on jumpers...

I will try cleaning up and post again. Thanks---bree