Hi there - two issues:
1) The ultrasound sensor reading sometimes jumps between the actual distance and strange readings (e.g. at 1.5m away, it might show 1.5m, but sometimes will jump to 0.8 or 3.7... 0.8 being the most frequent 'bad reading').
2) The ultrasound sensor reading sometimes is offset by a constant number upon startup (e.g. at 1.5m, it shows 2.2m, a constant offset of ~0.7-0.8m... at 1.7m, it shows 2.4m, a constant offset of ~0.8m).
There are enough features and SLAM quality is good.
Edit - I thought it was due to the props, but even with them off there is still 1) the constant offset issue of ~0.83, and 2) the weird jumping issue.
Edit 2 - A different time, the constant offset was by ~1.50. Nothing was in front of the Slamdunk upon startup.
Edit 3 - I ran "sudo diagnostic":
01-linux-version ok [system] Linux version
02-memory ok [system] Memory close to 2GB
03-linux-thermal ok [system] Linux thermal zones availability
04-cpu-governor ko [system] CPU governor
05-linux-sanity ko [system] Linux sanity
20-magnetometer ko [sensors/i2c] Dev ID of AK8963C magn on /dev/i2c-0 (Result: 0x0f)
21-barometer ko [sensors/i2c] Ping MS5607 barometer on /dev/i2c-0
22-codec ok [sensors/i2c] Ping ADAU1772 codec on /dev/i2c-0
25-ultrasound ko [ultrasound] Ultrasound Result: KO Distances: ""
30-camera ko [camera] Cameras acquisition
31-camera-freq ko [camera] Frequency Result: ms (33.33 ms) diff=-inf%
32-camera-conn ko [camera] Camera connection: Left is unknown and Right unknown
40-imu ok [imu] IMU Result: 15935 lines (16000) diff=0.41 %
Perhaps this issue coincides with my other issue - http://forum.developer.parrot.com/t/slam-axes-orientation-offset-error-on-startup/5445