This is a project I created several years ago and thought the members of this forum would enjoy it.
It is personal badge that is the same size as a normal business card that has the letters BOO that flashes and is powered by a CR2032 coin size lithium battery. It uses a pair of CMOS 555 timers. The one driving the PN2222 transistor has a flash rate of approximately 14mS. The other timer adjust the flash rate from less than a 10th of a scond to a little over 3 seconds. When the LEDs appear on they are in fact flashing, but the eye sees them continually on.
The circuit board is shown from the top of the board so it will have to be reversed on the bottom of the board. The switch shown in the picture is different from the parts list, as I used a sample I had in my stock.
The circuit board pattern will have to be adjusted for the switch shown in the parts list. The parts list switch has 3 terminals, only two are connected to the circuit.
The LEDs that I used are clear but illuminate in RED.
This is a parts list of the specific parts:
1. Battery Holder Renata, Mouser 614-HU2032-LF
2. On/Off switch, Alco, Mouser 506-SLS211RA04
3. 1M miniature trim pot,Vishay Mouser 72-T63ZB-1M
4. 555 CMOS TIMER, TI, Mouser 926-LMC555CN/NOPB
5. 3.3uF Radial electrolytic, Nichicon, Mouser 647-UMA1V3R3MDA
There are LEDs in each letter that are in parallel with one current limiting resistor. Schematic A(the first schematic posted) is a circuit to match the LEDs within 50mV of each other. On the circuit for the LED matcher the value of Rs is 620 ohms(Rs=2.5/ILED)
On the circuit for the LED matcher the value of Rs is 620 ohms(Rs=2.5/ILED)
I have 3 packages consisting of the CMOS 555'S, the new switch, the battery holder, and the miniature 3.3uF capacitor
that I will sell for $5.00 US dollars to USA members, postage paid.
The circuit board was home made.
It is personal badge that is the same size as a normal business card that has the letters BOO that flashes and is powered by a CR2032 coin size lithium battery. It uses a pair of CMOS 555 timers. The one driving the PN2222 transistor has a flash rate of approximately 14mS. The other timer adjust the flash rate from less than a 10th of a scond to a little over 3 seconds. When the LEDs appear on they are in fact flashing, but the eye sees them continually on.
The circuit board is shown from the top of the board so it will have to be reversed on the bottom of the board. The switch shown in the picture is different from the parts list, as I used a sample I had in my stock.
The circuit board pattern will have to be adjusted for the switch shown in the parts list. The parts list switch has 3 terminals, only two are connected to the circuit.
The LEDs that I used are clear but illuminate in RED.
This is a parts list of the specific parts:
1. Battery Holder Renata, Mouser 614-HU2032-LF
2. On/Off switch, Alco, Mouser 506-SLS211RA04
3. 1M miniature trim pot,Vishay Mouser 72-T63ZB-1M
4. 555 CMOS TIMER, TI, Mouser 926-LMC555CN/NOPB
5. 3.3uF Radial electrolytic, Nichicon, Mouser 647-UMA1V3R3MDA
There are LEDs in each letter that are in parallel with one current limiting resistor. Schematic A(the first schematic posted) is a circuit to match the LEDs within 50mV of each other. On the circuit for the LED matcher the value of Rs is 620 ohms(Rs=2.5/ILED)
On the circuit for the LED matcher the value of Rs is 620 ohms(Rs=2.5/ILED)
I have 3 packages consisting of the CMOS 555'S, the new switch, the battery holder, and the miniature 3.3uF capacitor
that I will sell for $5.00 US dollars to USA members, postage paid.
The circuit board was home made.
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