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Category: Tech

e-Bike Lithium Ion Load Tester

e-Bike Lithium Ion Load Tester

Using power resistors is not feasable, but AC halogen bulbs are easily sources up to 500W , so multiple bulbs can be used to vary the current 120 Vrms 500 bulb watts 28.8 bulb resistance 52 battery voltage 93.88889 watts 1.805556 amps So on a 52V battery pack a 500w halogen bulb would draw about 1.8Amps Voltage can be monitored with a simple voltage divider to lower the 52V to something suitable ( < 3v probably ) Current can be…

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HAProxy – Slowing down abuse with user friendly rate controls

HAProxy – Slowing down abuse with user friendly rate controls

There are various situations where clients can overload a website server, but you don’t want to return a 4xx or 5xx simply because the system is getting bogged down, instead it would be better to have a mechanism which tries to take the pressure off the backend server to give all clients a fair chance. Thankfully HAProxy has a couple of ways that requests can be slowed down on their way to the backend, the cleanest mechanism is to use…

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UAV parachute recovery system

UAV parachute recovery system

In the event that something goes horribly wrong while at high altitude it makes sense that things come back down under a bit of control! droneyard.com/2013/07/01/uav-parachute-recovery-system/ What i’m struggling to solve is how to design the deployment system so that it does not tangle around the props when the UAV is falling in a tumble. I’m currently imagining a tub with either spring loaded deployment mechanism or a ballistic launch system.

Programmable LED strips

Programmable LED strips

These are perfect for so many cool applications. I really want to upgrade the static red and white LED strips on my Quadcopter with these so that the whole strips and function as a white strobe as well as navaigation lights and also to show warning events, like low battery etc. 32 LEDs per meter – www.adafruit.com/products/306   60 LEDs per meter – www.adafruit.com/products/1461 Arduino code library –  github.com/adafruit/Adafruit_NeoPixel It is a shame that the newer 60 LEDs per meter…

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