I will see what I can do about the video, here are some shots of how it all fits together in the housing. The are other more RADAR-ish devices that really do measure the doppler effect but none of them look like they would really work, still waiting for a real radar to appear for hobbyists. It will run for at least one hour on a single charge. If you leave this on a nearby table and don’t move around too much and someone approaches the tracker starts going off and it is kind of creepy and fun. The animation and sound effects are fairly simple at this point. The aliens placement is random and the distance numbers change and are correct. When the motion detector board output goes high the aliens start appearing on the screen and come towards the bottom center in 3 waves. I didn’t want to use a Raspberry Pi a because even a Pi zero is a little too large and takes too long to boot and is power hungry and it should be doable with a micro-controller (and it is). I did a simulation of the filter characteristics in LTSpice and ended up with a voltage divider of 18k and a 1k pot with 100nf cap for the RC filter.Ĩ) PAM8403 23db fixed gain amp board – as is – the preamp board does the conditioning of the signal and volume controlġ0) “RADAR” board – this is not really radar – it is more just an RF motion detector that operates at just above 3ghz.

For some reason the makers of these tft boards like to lay them out in the worst way possible from a wasted space standpoint.Ģ) This is my go-to micro-controller board, small, cheap, quad flat pack with all pins accessible.ģ) 5v rail Bulk storage capacitor - the boost converter is tiny and needs some bulk storage on the 5v rail.Ĥ) 5v boost converter – made for drones – not the cheapest but very small and they work.ĥ) Standard 4056 based LiPo charger and protection board – modded with a 5.6k resistor in position R3 to limit the charge current to 210maĦ) Drone lipo battery – made for high charge and discharge currents, but I don’t push them that hard and keep the charge/discharge current under 1Cħ) “preamp” board – the audio amp board input is +/- 300mv and this board brings the 5v square waves coming out of the micro-controller down to max 300mv or less and also acts as a low pass filter to knock the rising edge and harmonics off the square waves and make them look more like sine waves. audio attenuation/volume control/low pass filterġ) I chose this particular TFT because the layout was just right and by cutting about a centimeter off of one side of the board you can get a centered tft panel without too much wasted space on the sides.

Aliens motion tracker sound