DIY Altitude Chamber

[Stogey]

Winter can be a good time to do stuff.
This winter three of us decided to learn about the electronics, characteristics, limitations, and capabilities of a couple different altitude recorders.
On the test bed: Jolly Logic's AltimeterThree, PerfectFlite's StratoLogger SL100, and EggTimers Quark.

The JL3 and SL100 are fully assembled and just about ready to fly out of the box, the EggTimer Quark requires assembly (at the component level - our build video is in work).

We wanted to comprehend the drogue deployment, main deployment, and altitude recording of the SL100 and Quark. The JL3 provided us with a device to compare the results along with readily accessible metrics (graphs and spreadsheets).

We discussed strapping a few Ms onto a lawn chair and going up with the computers to witness the apogee events and main chute events; we scrapped that idea when the wives began supporting the effort.
A moment of clarity came to Scott while in the shower... why not use the Food Saver with the marinating containers, put the devices inside and 'launch' them in our defacto altitude chamber!?

The rest is history... for your viewing pleasure; a test of the Quark & JL3, followed by a test of the SL100 & JL3, and finally, the Quark, SL100, and JL3 along for the same ride.

Quark and JL3
https://youtu.be/mepctW1FLaI

SL100 and JL3
https://youtu.be/aZWsy8mDUYM

Quark, SL100, JL3
https://youtu.be/e_KTH2DmwM0

 

[BDB]

Very interesting. I thought the Jolly Logic system calculated altitude using an accelerometer, not via barometric pressure. But it looks like I was wrong. Thanks for doing this.

 

[RocketFeller]

Very interesting. I thought the Jolly Logic system calculated altitude using an accelerometer, not via barometric pressure. But it looks like I was wrong. Thanks for doing this.

I believe the accelerometer equipped computers need to be oriented in a certain direction, which wouldn't work the way the Jolly Logic just hangs out.

 

[Stogey]

It (Jolly Logic AltimeterThree) does a bit of both...
Sampling Rate: Barometer: 31 times/second; Accelerometer: 244 times/second

Here's a Flight Graph from the AltimeterThree iOS App, below the image I have copied and pasted some of the data from the data dump:




Time Press Altitude Xacc Yacc Zacc TotalAcc
Pa feet
0.00 83485.00 -2.00 0.49 0.84 0.13 0.98
0.05 83487.00 -1.00 2.49 2.66 0.45 3.67
0.10 83572.00 0.00 7.66 9.46 4.20 12.87
0.15 83498.00 1.00 6.01 6.96 3.65 9.90
0.20 83479.00 2.00 5.26 6.63 2.77 8.90
0.25 83472.00 4.00 6.26 6.27 2.85 9.31
0.30 83466.00 7.00 6.13 6.63 3.22 9.58
0.35 83455.00 10.00 6.05 6.49 3.19 9.43
0.40 83450.00 13.00 6.07 6.31 3.27 9.35
0.45 83441.00 19.00 6.27 6.48 3.25 9.59
0.50 83424.00 24.00 6.47 6.50 3.55 9.83
0.55 83406.00 29.00 6.32 6.39 3.29 9.57
0.60 83389.00 34.00 6.44 6.48 3.25 9.70
0.65 83373.00 41.00 6.44 6.51 3.34 9.75
0.70 83352.00 47.00 6.02 6.51 3.39 9.49
0.75 83325.00 55.00 5.64 6.09 3.26 8.91
0.80 83301.00 63.00 5.55 5.82 3.41 8.73
0.85 83276.00 71.00 5.38 5.93 3.53 8.75
0.90 83243.00 80.00 5.31 5.82 3.53 8.63
0.95 83215.00 89.00 5.12 5.81 3.43 8.47
1.00 83181.00 99.00 4.80 5.32 3.27 7.88
1.05 83149.00 109.00 4.85 5.08 3.02 7.64
1.10 83120.00 119.00 4.83 4.83 2.86 7.41
1.15 83085.00 130.00 4.91 4.98 2.62 7.47
1.20 83052.00 142.00 4.76 4.61 2.42 7.05
1.25 83016.00 154.00 4.90 4.38 2.27 6.95
1.30 82977.00 166.00 4.87 4.38 2.10 6.88
1.35 82941.00 178.00 4.67 4.39 1.83 6.67
1.40 82900.00 191.00 4.24 4.57 1.76 6.48
1.45 82854.00 205.00 4.23 4.32 1.52 6.24
1.50 82812.00 218.00 3.99 4.06 1.78 5.96
1.55 82766.00 232.00 3.70 3.95 1.93 5.75
1.60 82719.00 247.00 3.55 3.79 1.89 5.53
1.65 82673.00 262.00 3.67 3.47 1.64 5.31
1.70 82627.00 277.00 3.70 3.21 1.60 5.15
1.75 82583.00 293.00 3.56 2.96 1.52 4.88
1.80 82536.00 309.00 3.39 2.88 1.18 4.61
1.85 82484.00 325.00 3.08 2.77 1.06 4.28
1.90 82430.00 341.00 2.87 2.67 0.80 4.00
1.95 82381.00 358.00 2.64 2.53 0.68 3.72
2.00 82320.00 375.00 2.57 2.26 0.55 3.47
2.05 82266.00 393.00 2.29 1.65 0.41 2.85
2.10 82213.00 411.00 1.80 1.31 0.34 2.26
2.15 82158.00 429.00 1.29 0.86 0.07 1.55
2.20 82103.00 448.00 0.77 0.41 -0.24 0.91
2.25 82039.00 466.00 0.57 0.14 -0.40 0.71
2.30 81982.00 486.00 0.26 -0.04 -0.60 0.66
2.35 81920.00 504.00 0.08 0.01 -0.52 0.53
2.40 81857.00 524.00 0.38 -0.27 -0.01 0.47
2.45 81794.00 543.00 1.24 -1.15 0.10 1.69
2.50 81741.00 562.00 -1.26 -0.79 -1.01 1.80
2.55 81684.00 581.00 0.06 -1.14 -2.53 2.77
2.60 81617.00 600.00 -1.01 -0.12 -1.13 1.53
2.65 81562.00 619.00 -0.55 -0.20 -0.87 1.05
2.70 81504.00 638.00 -0.50 -0.23 -0.86 1.02
2.75 81451.00 656.00 -0.50 -0.17 -0.82 0.98
2.80 81398.00 675.00 -0.52 -0.13 -0.78 0.95
2.85 81339.00 693.00 -0.54 -0.12 -0.71 0.90
2.90 81278.00 712.00 -0.55 -0.14 -0.74 0.93
2.95 81225.00 730.00 -0.50 -0.15 -0.73 0.90
3.00 81168.00 748.00 -0.46 -0.20 -0.77 0.92
3.05 81116.00 766.00 -0.48 -0.19 -0.73 0.90
3.10 81056.00 784.00 -0.49 -0.08 -0.67 0.83
3.15 81005.00 802.00 -0.51 -0.08 -0.67 0.85
3.20 80946.00 820.00 -0.50 -0.11 -0.69 0.86
3.25 80892.00 837.00 -0.47 -0.16 -0.64 0.81
3.30 80841.00 855.00 -0.48 -0.16 -0.65 0.82
3.35 80792.00 872.00 -0.49 -0.14 -0.72 0.88
3.40 80737.00 889.00 -0.44 -0.15 -0.64 0.79
3.45 80686.00 906.00 -0.43 -0.17 -0.61 0.77
3.50 80633.00 924.00 -0.49 -0.15 -0.56 0.76
3.55 80579.00 940.00 -0.45 -0.08 -0.54 0.71
3.60 80533.00 957.00 -0.43 -0.10 -0.64 0.77
3.65 80479.00 973.00 -0.40 -0.14 -0.70 0.82
3.70 80423.00 990.00 -0.41 -0.17 -0.67 0.80
3.75 80382.00 1006.00 -0.42 -0.11 -0.52 0.68
3.80 80328.00 1022.00 -0.41 -0.13 -0.49 0.65
3.85 80281.00 1038.00 -0.43 -0.10 -0.49 0.66
3.90 80234.00 1054.00 -0.40 -0.07 -0.50 0.64
3.95 80193.00 1070.00 -0.38 -0.11 -0.56 0.68
4.00 80146.00 1085.00 -0.40 -0.12 -0.49 0.64
4.05 80097.00 1101.00 -0.33 -0.13 -0.56 0.66
4.10 80048.00 1116.00 -0.34 -0.06 -0.59 0.69
4.15 80001.00 1131.00 -0.35 -0.04 -0.53 0.64
4.20 79955.00 1146.00 -0.39 -0.05 -0.49 0.63
4.25 79910.00 1161.00 -0.30 -0.09 -0.46 0.56
4.30 79867.00 1176.00 -0.36 -0.09 -0.46 0.59
4.35 79822.00 1191.00 -0.35 -0.07 -0.48 0.60
4.40 79778.00 1206.00 -0.34 -0.08 -0.52 0.62
4.45 79734.00 1220.00 -0.33 -0.10 -0.49 0.60
4.50 79695.00 1235.00 -0.26 -0.11 -0.52 0.59
4.55 79645.00 1249.00 -0.29 -0.06 -0.51 0.59
4.60 79601.00 1263.00 -0.33 -0.04 -0.40 0.52
4.65 79561.00 1277.00 -0.33 -0.05 -0.37 0.50
4.70 79518.00 1291.00 -0.32 -0.04 -0.40 0.51
4.75 79475.00 1305.00 -0.32 -0.11 -0.40 0.52
4.80 79435.00 1319.00 -0.29 -0.10 -0.38 0.49
4.85 79399.00 1332.00 -0.28 -0.11 -0.43 0.52
4.90 79359.00 1346.00 -0.26 -0.07 -0.49 0.56
4.95 79314.00 1359.00 -0.31 -0.07 -0.44 0.54
5.00 79271.00 1372.00 -0.30 -0.01 -0.43 0.53
5.05 79238.00 1385.00 -0.24 -0.05 -0.44 0.50
5.10 79200.00 1398.00 -0.28 -0.03 -0.45 0.53
5.15 79160.00 1411.00 -0.28 -0.01 -0.33 0.43
5.20 79122.00 1423.00 -0.28 -0.08 -0.34 0.45
5.25 79089.00 1436.00 -0.26 -0.10 -0.41 0.50
5.30 79045.00 1449.00 -0.21 -0.08 -0.38 0.44
5.35 79014.00 1461.00 -0.24 -0.08 -0.44 0.50
5.40 78978.00 1473.00 -0.24 0.01 -0.41 0.48
5.45 78935.00 1485.00 -0.26 0.01 -0.38 0.46
5.50 78899.00 1497.00 -0.23 -0.02 -0.36 0.43
5.55 78866.00 1509.00 -0.24 -0.08 -0.36 0.44
5.60 78828.00 1521.00 -0.20 -0.10 -0.38 0.44
5.65 78794.00 1533.00 -0.21 -0.13 -0.33 0.41
5.70 78762.00 1545.00 -0.17 -0.06 -0.39 0.43
5.75 78724.00 1557.00 -0.23 0.00 -0.36 0.43
5.80 78688.00 1568.00 -0.21 0.03 -0.31 0.37
5.85 78659.00 1579.00 -0.21 -0.01 -0.31 0.38
5.90 78627.00 1590.00 -0.21 -0.05 -0.33 0.39
5.95 78590.00 1601.00 -0.20 -0.04 -0.39 0.44
6.00 78558.00 1612.00 -0.19 -0.04 -0.27 0.33
6.05 78522.00 1623.00 -0.18 -0.04 -0.33 0.38
6.10 78496.00 1634.00 -0.17 -0.03 -0.33 0.37
6.15 78464.00 1645.00 -0.18 -0.01 -0.32 0.36
6.20 78430.00 1655.00 -0.19 -0.04 -0.33 0.38
6.25 78401.00 1666.00 -0.20 -0.02 -0.28 0.35
6.30 78369.00 1676.00 -0.18 -0.02 -0.30 0.35
6.35 78335.00 1686.00 -0.18 -0.03 -0.32 0.37
6.40 78308.00 1697.00 -0.13 -0.02 -0.32 0.34
6.45 78276.00 1707.00 -0.15 0.01 -0.33 0.37
6.50 78248.00 1717.00 -0.16 0.01 -0.35 0.38
6.55 78224.00 1727.00 -0.12 -0.05 -0.35 0.38
6.60 78192.00 1737.00 -0.13 -0.06 -0.31 0.34
6.65 78158.00 1747.00 -0.12 -0.03 -0.33 0.36
6.70 78132.00 1756.00 -0.15 0.01 -0.31 0.34
6.75 78103.00 1766.00 -0.15 0.04 -0.31 0.35
6.80 78076.00 1775.00 -0.09 0.02 -0.34 0.35
6.85 78047.00 1785.00 -0.13 0.04 -0.31 0.34
6.90 78016.00 1794.00 -0.14 0.02 -0.24 0.28
6.95 77990.00 1803.00 -0.14 0.00 -0.24 0.28
7.00 77966.00 1812.00 -0.15 -0.02 -0.27 0.31
7.05 77937.00 1821.00 -0.10 -0.04 -0.27 0.29
7.10 77914.00 1830.00 -0.07 -0.05 -0.30 0.32
7.15 77885.00 1839.00 -0.07 -0.04 -0.31 0.32
7.20 77857.00 1848.00 -0.06 -0.03 -0.32 0.33
7.25 77840.00 1856.00 -0.07 0.00 -0.32 0.33
7.30 77813.00 1864.00 -0.09 0.02 -0.35 0.36
7.35 77788.00 1873.00 -0.08 0.00 -0.33 0.34
7.40 77757.00 1881.00 -0.08 -0.02 -0.33 0.34
7.45 77738.00 1889.00 -0.09 -0.01 -0.28 0.29
7.50 77716.00 1897.00 -0.05 -0.01 -0.25 0.26
7.55 77693.00 1905.00 -0.05 0.01 -0.29 0.29
7.60 77666.00 1913.00 -0.09 0.05 -0.26 0.28
7.65 77642.00 1921.00 -0.05 0.04 -0.27 0.28
7.70 77620.00 1929.00 -0.08 0.00 -0.21 0.22
7.75 77601.00 1936.00 -0.07 0.00 -0.26 0.27
7.80 77576.00 1944.00 -0.05 0.00 -0.28 0.29
7.85 77556.00 1951.00 -0.06 -0.08 -0.27 0.28
7.90 77537.00 1959.00 -0.05 -0.06 -0.20 0.22
7.95 77511.00 1966.00 -0.04 -0.05 -0.23 0.24
8.00 77490.00 1974.00 -0.03 -0.07 -0.24 0.25
8.05 77467.00 1981.00 -0.05 -0.01 -0.27 0.27
8.10 77444.00 1988.00 0.01 0.04 -0.37 0.37
8.15 77425.00 1995.00 -0.03 0.05 -0.33 0.34
8.20 77400.00 2002.00 -0.01 0.05 -0.35 0.35
8.25 77382.00 2009.00 -0.02 0.03 -0.35 0.35
8.30 77364.00 2016.00 -0.01 0.02 -0.30 0.31
8.35 77345.00 2022.00 0.00 0.04 -0.29 0.29
8.40 77325.00 2029.00 0.00 0.04 -0.26 0.26
8.45 77305.00 2036.00 -0.02 0.03 -0.25 0.26
8.50 77288.00 2042.00 -0.04 0.00 -0.23 0.23
8.55 77272.00 2048.00 -0.05 0.03 -0.18 0.19
8.60 77251.00 2055.00 -0.04 -0.01 -0.16 0.16
8.65 77235.00 2061.00 -0.05 0.04 -0.16 0.17
8.70 77213.00 2067.00 -0.04 0.03 -0.14 0.15
8.75 77195.00 2073.00 -0.04 0.04 -0.16 0.17
8.80 77174.00 2079.00 -0.04 -0.04 -0.19 0.20
8.85 77161.00 2085.00 -0.02 0.04 -0.20 0.21
8.90 77142.00 2091.00 -0.02 -0.02 -0.23 0.23
8.95 77130.00 2096.00 0.01 -0.01 -0.21 0.21
9.00 77112.00 2102.00 0.01 -0.02 -0.25 0.25
9.05 77098.00 2107.00 0.01 -0.01 -0.25 0.25
9.10 77078.00 2113.00 0.02 -0.05 -0.25 0.26
9.15 77061.00 2118.00 0.01 -0.09 -0.22 0.24
9.20 77047.00 2123.00 0.04 -0.08 -0.22 0.23
9.25 77036.00 2129.00 0.02 -0.08 -0.18 0.20
9.30 77024.00 2134.00 0.00 -0.03 -0.19 0.20
9.35 77003.00 2139.00 0.03 -0.01 -0.20 0.20
9.40 76989.00 2144.00 -0.01 0.01 -0.19 0.19
9.45 76974.00 2149.00 0.00 0.01 -0.19 0.19
9.50 76960.00 2154.00 -0.01 0.05 -0.24 0.24
9.55 76945.00 2158.00 0.01 0.06 -0.25 0.25
9.60 76929.00 2163.00 0.03 0.05 -0.27 0.27
9.65 76917.00 2168.00 0.01 0.06 -0.26 0.27
9.70 76905.00 2172.00 0.02 0.05 -0.25 0.26
9.75 76894.00 2177.00 0.03 0.04 -0.25 0.26
9.80 76880.00 2181.00 0.04 0.03 -0.23 0.23
9.85 76868.00 2185.00 0.05 0.04 -0.26 0.27
9.90 76856.00 2189.00 0.04 0.04 -0.24 0.25
9.95 76845.00 2193.00 0.04 0.02 -0.25 0.25
10.00 76833.00 2197.00 0.03 0.03 -0.22 0.23
10.05 76821.00 2201.00 0.03 0.02 -0.22 0.22
10.10 76808.00 2205.00 0.03 0.02 -0.23 0.23
10.15 76797.00 2209.00 0.04 0.05 -0.24 0.25
10.20 76789.00 2212.00 0.03 0.07 -0.25 0.26
10.25 76781.00 2216.00 0.03 0.08 -0.21 0.22
10.30 76765.00 2219.00 0.04 0.06 -0.23 0.24
10.35 76756.00 2225.00 0.03 0.06 -0.23 0.24
10.40 76748.00 2226.00 0.05 0.05 -0.23 0.24
10.45 76739.00 2233.00 0.04 0.05 -0.25 0.26
10.50 76734.00 2237.00 0.04 0.06 -0.23 0.24
10.55 76721.00 2245.00 0.06 0.05 -0.24 0.25
10.60 130845.00 2249.00 8.75 2.54 3.44 9.74
10.65 76610.00 2254.00 -0.57 1.64 1.43 2.25
10.70 76767.00 2258.00 1.53 1.85 -3.10 3.92
10.75 76531.00 2261.00 -0.63 0.13 -1.34 1.49
10.80 76667.00 2265.00 -1.65 2.99 -2.16 4.04
10.85 76479.00 2269.00 1.14 1.36 -1.47 2.31
10.90 76637.00 2273.00 -3.97 14.14 -10.41 18.00
10.95 76581.00 2278.00 0.27 0.06 -4.87 4.88
11.00 76604.00 2280.00 -0.20 1.43 -3.61 3.89
11.05 76608.00 2286.00 -0.38 7.52 -2.63 7.98
11.10 76586.00 2285.00 0.47 3.97 -0.61 4.04
11.15 76598.00 2287.00 -0.67 0.67 -1.55 1.82
11.20 76562.00 2283.00 1.09 5.98 -0.77 6.13
11.25 76535.00 2284.00 0.08 4.04 1.07 4.18
11.30 76542.00 2284.00 0.70 4.18 1.09 4.37
11.35 76538.00 2285.00 1.05 5.63 0.55 5.75
11.40 76572.00 2286.00 0.86 5.35 0.35 5.43
11.45 76598.00 2286.00 0.76 4.66 -0.04 4.72
11.50 76614.00 2286.00 0.91 4.85 -0.33 4.95
11.55 76603.00 2286.00 0.87 4.30 -0.48 4.41
11.60 76586.00 2284.00 0.64 2.97 -0.26 3.05
11.65 76574.00 2283.00 0.15 1.88 -0.34 1.92
11.70 76568.00 2282.00 -0.14 1.19 -0.49 1.30
11.75 76585.00 2282.00 -0.02 1.48 -0.33 1.52
11.80 76579.00 2282.00 -0.01 1.24 -0.39 1.30
11.85 76593.00 2283.00 0.12 0.73 -0.81 1.09
11.90 76593.00 2283.00 0.26 0.56 -0.65 0.89
11.95 76574.00 2283.00 0.38 1.54 -0.13 1.60
12.00 76576.00 2283.00 -0.11 0.40 -0.06 0.42

 

[John Beans]

Don't forget to update the AltimeterThree app on your phone.
Go to the app store and search for "AltimeterThree" (all one word) and install the latest version.


Some of these analyses will not work in a vacuum chamber (like ejection detection), but you'll appreciate them for actual launches, and it's got a special "Chute Release" aware descent rate feature that shows tumbling/drogue descent rate and a second landing descent rate.

 

[Stogey]

John -- thanks for the reply.
I'm running the most current software - none of the additional features are displayed since this was a simulated flight in a DIY altitude chamber (e.g., no G forces, nothing on the accelerometers, etc.)

 

[Stogey]

Note to anyone watching... the little DIY altitude chamber experiment paid for the time and energy.

We bought three Egg Timer Quarks, one for two adults and one teenager, moderate soldering skills for the adults, and a new experience for the youngin.

We built one Quark - tested, all was right (startup, tones, continuity on LEDs [simulated ematch], and firing of drogue/main charges [again LEDs simulated the output])
Built the next Quark - tested, all was right
The last Quark was assembled, startup was good, good tones, continuity on LEDs, and ready for launch signal. When we did the altitude chamber test, the apogee event did not occur (the LED did not get super bright like the other two tests), however, the main chute event (approx. 500' AGL) did occur.
We're troubleshooting the possibilities (EggTimer customer support has provided rapid responses) and hope for full resolution.

The key to this, I asked the youngin - "Imagine if that was in your rocket, and the drogue chute did not fire"; he immediately realized the value of the simplistic test.

So, proof of concept - at least on a barometric level. We'll have to trip the accelerometers through an actual launch!

 

[John Beans]

John -- thanks for the reply.
I'm running the most current software - none of the additional features are displayed since this was a simulated flight in a DIY altitude chamber (e.g., no G forces, nothing on the accelerometers, etc.)

Which version is shown in Settings (the gear menu in the app)?

 

[Stogey]

Which version is shown in Settings (the gear menu in the app)?

App: 3.1.5012
AltimeterThree: 2.28

 

[BDB]

So if the JL Altimeter 3 uses a barometric sensor to detect altitude, do I need to put a vent hole in the rocket if it is enclosed in the payload section of a LPR kit? Maybe that explains the weird data from my son's Estes HyperBat.

 

[cerving]

So if the JL Altimeter 3 uses a barometric sensor to detect altitude, do I need to put a vent hole in the rocket if it is enclosed in the payload section of a LPR kit? Maybe that explains the weird data from my son's Estes HyperBat.
View attachment 311027

That spike is where your motor's ejection charge went off, since it's external to the electroncs it will show up as pressure spike. Totally normal for recording baro altimeters.

 

[John Beans]

So if the JL Altimeter 3 uses a barometric sensor to detect altitude, do I need to put a vent hole in the rocket if it is enclosed in the payload section of a LPR kit? Maybe that explains the weird data from my son's Estes HyperBat.
View attachment 311027

Yes, you do need venting. The payload looks likes it's not airtight (or you wouldn't have shape to your graph at all), but it does look somewhat distorted.
And a couple of the analyses were knocked off (including ejection detection and apogee). Showing the acceleration components can help complete the story of what really went on. Some sort of acceleration led to the determination of ejection there during coast, but from the altitude graph it's obviously not an actual ejection (rockets can coast upward to that extent after coming apart).

Start by showing Total Acceleration (which combines all directions), see what that tells you, and then consider just showing the component that is in the direction of flight (usually Y if the long dimention of the altimeter is aligned with the rocket). You should be able to figure out when actual ejection was.

That spike does look like it coincides with ejection, but whether it's a direct pressure spike or an "air hammer" caused by acceleration of air in a closed container I can't say. Most of those spikes get filtered out, but this one didn't for some reason.