Uses a 12 key keyboard and texts like an old Nokia phone with multiple keypresses. http://www.technoblogy.com/show?2AON&fbclid=IwQ0xDSwL88ShjbGNrAvzr1WV4dG4DYWVtAjExAAEeX19OxuYe1QO8mrox71F6Zl_KCUppukTfJn3iSrHyEVT51xLwOmz2jhPHLKY_aem_is4HJCST113TNXDXWaTXGw
Archive for the ‘Schematics’ Category:
2024-09-20 Simple 1 Digit Counter, IR Beam Break
This short uses a CD4026, a 7 segment display, 9V battery, some resistors, an IR LED and a CdS photocell or phototransistor. Break the IR beam and the display advances to the next digit. https://www.facebook.com/reel/525596709839365?mibextid=9drbnH
2024-08-31 AM Transmitter, Low Power
This is an AM transmitter that this guy built. He says it’s rich in harmonics – it has no tuning nor low pass filtering and the stages are class C, no forward bias. It should have all the things used to minimize harmonics, like a low pass filter. Class C operation is used to maximize
(Read More…)
2024-08-21 Adjustable Power Supply Uses Sziklai Pair
This messy bunch of parts is a 0 to 9V adjustable power supply. The original power supply board connected the two transistors in the Darlington Configuration. The unregulated 12V input goes through a 187 ohm resistor to a 10V zener diode to give a stable reference voltage. This voltage is fed to a 2.5k linear
(Read More…)
2024-08-21 Video: Build An FM Microphone
This 2.5 min video uses a SS8050 transistor which is not very good for a 100 MHz oscillator. https://www.facebook.com/reel/347155875050146?mibextid=9drbnH&s=yWDuG2&fs=e
2024-04-20 RCWL-0516 Microwave Doppler Motion Sensor Module Schematic KO4BB
The modules use both the RCWL-9616 and the BISS-0001 but it seems the schematics are all labeled BISS-0001. The parts values are different. He gives some good information about them. They operate at 3.5 and 3.98 GHz – the ones I have were advertised at 5 GHz. Also he shows his own version that uses a
(Read More…)
2024-04-10 FM Regenerative Receiver Using MPF102 JFET
A basic one transistor regen receiver uses an MPF102 JFET to give the regenerative gain. Also uses two transistors to amplify the audio to drive an earphone. https://www.circuitbasics.com/what-are-fm-receivers/
2024-03-29 FM Crystal Set Uses Helical Resonator For Tuning
This is a long article but a very interesting project. It uses HSMS-2850 Schottky detector diodes in a discriminator. He uses WE 1200 ohm sound powered headphones. He’s Canadian. https://electronbunker.ca/eb/FMCrystalSet.html
2024-03-10 Radio Shack P-Box List, Assembly Manual, Schematic Info
This seems to be pretty much all of the kits. http://my.core.com/~sparktron/pbox.html
2024-03-09 Big Clive’s Old Tungsten Roadwork Beacon – Barricade Flasher
I built this “tungsten roadwork beacon” as Clive calls it, using the parts given in my schematic (photo below). I didn’t have a 6V, 90 mA lamp, so I simulated it by using three 20 ohm, 1/4 Watt resistors in series, which gives 60 ohms and 100 mA load with 6VDC. For an indicator I
(Read More…)
