FAQ

Which devices is the MMC app compatible with?

Any phone that supports Bluetooth Low Energy (BLE), such as:

Apple:
iPhone 4S, iPhone 5/5C/5S, iPad (3rd gen & 4th gen), iPad Mini (Apple devices require iOS 5 or later)

Android:
HTC One, One X+, Droid DNA, Samsung Galaxy Nexus, Galaxy SIII, Galaxy S4, Note II.

Is there a safety/security concern regarding accidental ignitions?

As far as malicious/accidental launches from interference or other phones, it will protect against that. BLE has encrypted PKI authentication. The app will let you set an identifier for your phone.

The key safety mechanism overall is that you don’t plug the firing cable in till you’re ready to launch. There is a master switch as well on the case in addition to an LCD indicating status of the system. Ultimately there is always a chance that the hardware or firmware will fail. The only completely reliable safety is the lack of connectivity (physical cable going to the igniter being disconnected).

Keep in mind that the current leading model rocket launchers do not have this as a safety feature (the removable launch cable). While the key-in-launcher system is perfectly safe in practice, with our version you can plainly SEE that the thing is disconnected and can’t fire. That beats a child holding the launcher isn’t jamming something into the keyhole. We feel our system can be more secure if used properly.

Is it possible for me to write my own software interface to it (either do my own app or via Ardruino/rPi)?

As for “hacker” accessibility, we are fine with publishing schematics and the BLE protocol we use. In addition, we figure we’d keep the female headers – the ones we had in the prototype – in the production version, as well as keeping the BLE (male) programming header in place. These allow testing/troubleshooting for us, as well as last minute reprogramming. Hackers can use these to reprogram the BLE module itself or monitor/control it.

Do any warranties apply?

We are nice guys and will definitely help out. Contact us with whatever problems you have encountered.

What is the range possible between my smartphone and the MMC?

We are using Bluetooth Low Energy (BLE) which has a nominal range of 160 ft (50 m). This project is aimed squarely at the “sunday afternoon with kids” “Estes rockets” market. Hope this helps put things into perspective. Our target audience is NOT the HPR crowd.

Is it possible to have interference issues?

In terms of radio noise triggering the device, that is impossible. The mobile device communicates with our MMC launch box using the Bluetooth Low Energy (BLE) protocol. The BLE module in the launcher contains an embedded microcontroller that controls and monitors the launch circuitry. The only way that the launcher will fire the igniter is if it receives a properly formatted, authenticated bluetooth protocol message. This is definitely NOT a “see this radio frequency, turn on a switch” type device. See http://en.wikipedia.org/wiki/Bluetooth and http://en.wikipedia.org/wiki/Bluetooth_low_energy for more background information. By way of analogy, there are no circumstances under which rubbing a 9V battery on your HDMI cable would put your picture on the TV or interference on your WiFi causing you to accidentally receive a copy of Microsoft Office. This is the same thing.In terms of accidental or malicious launching by third parties, the mobile device and launcher are associated using BLE pairing and bonding. Launch (and other) messages are encrypted and authenticated. See http://en.wikipedia.org/wiki/Bluetoo…ng_and_bonding for more background information. No one else can fire your rocket.

What are some other safety mechanisms?

The cable running from the launch box to the igniter is removable at the launch box end. We are using a simple and easy to remove connector. The safety protocol is that you only plug the cable into the launcher after you have attached the clips and walked away.The launcher detects and reports the following conditions, which are indicated on the launch box with LED’s, and also on the app immediately (which is great for instant troubleshooting): 1) launch cable disconnected, 2) launch cable connected but igniter connection open (broken), and 3) igniter short circuited (wires touching somewhere). For those who want the technical details, this is accomplished with Four-terminal sensing. See http://en.wikipedia.org/wiki/Four-terminal_sensing for background information.

Are the hook clips good enough for my igniters?

The current requirement to reliably fire an Estes igniter with no perceptible delay is approx 1.5 Amps. The igniter fire time is less than one second. The hook clips used in the project are rated for 5.9 Amps (continuous duty).

Are these model rockets re-usable?

The model rockets we supply are reusable. You can send them up for multiple launches. You just need extra engines and igniters.

What are “A” Engines and Igniters?

An “A” sized engine represents the physical size of the engine and the amount of power it has to launch. A/B/C engines are all the same size. B engines are twice as powerful as an A and C engines are twice as powerful as a B (so four times more than an A). This is needed sometimes for heavier/larger rockets, or if you want to launch a lot higher.The A engine kits provided as perks are ideal for beginners. You could launch in a football field sized area. The higher you go with stronger engines, the more space you need to have due to wind potentially carrying your model rocket back (it has a parachute that ejects near the height of the launch).Our beginner kit includes 3 engines and igniters so you can launch 3 times. It is very inexpensive to buy more engines if you really like it to launch your rocket some more. You can decide if you want to go with B or C sized engines which will also fit in the model rocket we supply. You can also use the MMC and launch pad to launch other model rockets. You will have what you need, so this gets you started in a great hobby.