Summer is coming

Discussion about deployment systems including altimeters, timers, air speed flaps, servo systems, and chemical reactions.
Tony
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Summer is coming

Post by Tony »

I connected power to the HK-Altimeter from the VCC and Ground posts on the MSP430 Launchpad (running the ServoChron II software :cl: ) and it seems to power up okay :saber: . Does anyone know of any potential problems with powering up in this manner? (I'm learning basic electronics with MSP430 and Arduino and a breadboard, :ugh: but still don't trust myself to not mess something up BO: ).
Here is the MSP430 without servos connected.
Here is the MSP430 without servos connected.
100_6659.JPG (1.54 MiB) Viewed 29 times


First Launch was beautiful, low altitude flight with a added weight of payload but high enough for full parachute deployment at approx. 3.5 seconds. It looked to be just past apogee, rocket was falling but not very fast when the parachute door popped open. :cl:

HK-A data shows a 200' apogee, but no descent. DOH: Launch detected in first 3 seconds (which makes no sense because it should have been recording data the whole time I was pressurizing) and then just stays at apogee SC: . This is supposed to be a logging altimeter, not a peak only altimeter (right? DOH: ) ...or perhaps this is not a good power source.

I'm going to make a separate small power source for the altimeter so I can use it on other rockets... the skinny ones that go so high. RAT:

A very nice day to play in Reno.
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SaskAlex
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Re: Summer is coming

Post by SaskAlex »

I'm pretty sure the VCC on the MSP430 is only 3.6V. It's probably just barely enough to power the altimeter, and the altimeter was turning on and off (Hobby King site says HK-A needs an input voltage of 3.7-8.4V). Can you power the HK-A directly with whatever you are powering the launchpad with?
Tony
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Re: Summer is coming

Post by Tony »

Launchpad is powered by a 9v battery... so dont want to go direct to HK-A ... which also powers the servos. I want to re-design it so my switch turns those off too (didn't think it out when I built the wiring harness). Also I need a new battery in my voltmeter so I can test for any Launchpad pin giving 5v... unless someone already knows.

Otherwise I just need to rig up a watch-battery pack for the altimeter, which is a project already scheduled.
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U.S. Water Rockets1
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Re: Summer is coming

Post by U.S. Water Rockets1 »

Tony wrote:Launchpad is powered by a 9v battery... so dont want to go direct to HK-A ... which also powers the servos. I want to re-design it so my switch turns those off too (didn't think it out when I built the wiring harness). Also I need a new battery in my voltmeter so I can test for any Launchpad pin giving 5v... unless someone already knows.

Otherwise I just need to rig up a watch-battery pack for the altimeter, which is a project already scheduled.

The launchpad is happy running off a single LiPo battery. That should be enough to run your altimeter too. If you run the launchpad from a 9V battery then you have to use the 3.6V VCC on the board to run your servos. If you do that it is probably likely that the servo moving put enough drain on the 3.6V supply to shut off your altimeter.

The LiPo setup is better for this because the altimeter will be connected to the LiPo directly, and will not be on the low voltage side of the voltage regulator, which is limited to about 500mA total power. The LiPo can put out a lot more amps than the regulator.
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