Hi All- there are a number of terrific devices available to the rocketeer these days, each with unique attributes, and with worthy price-points. I'm not a new vendor (I'm a BAR), I'm not an EE, I'm just a dude with limited funds to spend on a hobby who has a couple of alternate designs to test out. The concepts work on breadboard, and I'm looking to scale up through a micro-startup firm like seeedstudio. This means I have to buy a minimum of 5 boards, which I'm happy to do, but I'd be even happier if I could gauge interest in the final products. I'm sure there are better ways of conducting Voice Of the Customer Research, but I'm not looking to retire, just hoping to pique the interest of a few intrepid explorers. When I prove that the designs work, I will be hoping to commercialize the overrun- this is between 5 and 10 boards, depending on how they pannelize.
Anyway- Up for your consideration are the following two prototypes- even if you wouldn't accept one if it were a door prize, I would like your opinion and feedback!
1) Programmable timer - there are a few of these out there, so what makes mine unique? It's field programmable and indicated by switch position- no rotary potentiometers to leave you guessing (no PC needed) to any interval from 1-256 seconds (4"16sec). This is a huge range, and so can provide redundant apogee charge (set it to the motor burn time +1 sec to avoid multiple charges), it can also provide intermediate drogue deploy (if your motor charge/altimeter drogue charge fails, this can be set to deploy a period of time after expected drogue- if motor eject or altimeter eject worked, this is a cheap insurance policy!). Another use, however, is it's ability to operate as an air-start timer for clusters and staged configurations. Unlike other timers I've seen, this one is strictly linked to Gs, and the threshold can be customized. Other timers use reed switches, that can be fooled with g-force, or, worse yet, start timing from power-on- we all know that's a recipe for disaster!)
2) Visual Cues- the circuit requires positive Gees for >0.5 second to acknowledge flight. This kicks off the timer. After that, the G switch could fall off, and the cycle would complete (but just handling the rocket on the table is unlikely to trigger a false positive launch (see Section 3 for more)! While on the pad it includes such niceties as "power LED" to show it's powered on, "continuity LED" to show that the ejection charge is connected, and, once it lands, it features a special latched circuit that holds the FIRED LED on, so you know it's safe to approach. This output can be coupled with a siren to help you find your rocket, if desired!
3) Audible Cues- We all know that when working on a rocket, particularly complex ones, we can get tunnel vision! When in that mode of work, having visual cues to warn the user are not effective, so my design includes a beeper that is activated with the timing circuit. It beeps once per second once the G-switch circuit is activated. IF you should be unfortunate enough to have wired up your ejection charge, without safeing the circuit, the beeper will indicate that a discharge is pending- this is also useful to test out the circuit prior to launch by counting the beeps and knowing that your charge will fire!
Also up for consideration is a magnetic activation switch- this allows you to arm/acknowledge/safe virtually any electronics system without physical contact. What does this mean? Instead of having a rotary switch to arm your altimeter, you have a decal over an area of the tube on which you apply a magnet (provided, but also available from almost any fridge in a pinch!). The status of the switch may be indicated via LED , which shines through a thinned area of the cardboard tube/poly nose. The stronger the magnet, and the brighter the LED, the less modification you have to do. The unit may ship with a neodymium magnet that will work through 1/4" of non-ferrous material. I say "may" because I have neither inventory nor a business plan to retire on this. What I can say is that it will likely be significantly less expensive than the other magnetic switches on the market. My hope is to gauge interest, and even if there is no interest, I'm happy let folks know that it's possible to improve it. What sets this apart critically is that it is all solid-state, there are no moving parts like you'd find in a reed switch, so G-force in any direction would have no impact on the switch.
Combined, these two improvements can deliver safe dual deploy to motor-eject low and mid-power rockets, or provide redundancy for motor eject/ main deployment of small high power rockets.
Anyway- Up for your consideration are the following two prototypes- even if you wouldn't accept one if it were a door prize, I would like your opinion and feedback!
1) Programmable timer - there are a few of these out there, so what makes mine unique? It's field programmable and indicated by switch position- no rotary potentiometers to leave you guessing (no PC needed) to any interval from 1-256 seconds (4"16sec). This is a huge range, and so can provide redundant apogee charge (set it to the motor burn time +1 sec to avoid multiple charges), it can also provide intermediate drogue deploy (if your motor charge/altimeter drogue charge fails, this can be set to deploy a period of time after expected drogue- if motor eject or altimeter eject worked, this is a cheap insurance policy!). Another use, however, is it's ability to operate as an air-start timer for clusters and staged configurations. Unlike other timers I've seen, this one is strictly linked to Gs, and the threshold can be customized. Other timers use reed switches, that can be fooled with g-force, or, worse yet, start timing from power-on- we all know that's a recipe for disaster!)
2) Visual Cues- the circuit requires positive Gees for >0.5 second to acknowledge flight. This kicks off the timer. After that, the G switch could fall off, and the cycle would complete (but just handling the rocket on the table is unlikely to trigger a false positive launch (see Section 3 for more)! While on the pad it includes such niceties as "power LED" to show it's powered on, "continuity LED" to show that the ejection charge is connected, and, once it lands, it features a special latched circuit that holds the FIRED LED on, so you know it's safe to approach. This output can be coupled with a siren to help you find your rocket, if desired!
3) Audible Cues- We all know that when working on a rocket, particularly complex ones, we can get tunnel vision! When in that mode of work, having visual cues to warn the user are not effective, so my design includes a beeper that is activated with the timing circuit. It beeps once per second once the G-switch circuit is activated. IF you should be unfortunate enough to have wired up your ejection charge, without safeing the circuit, the beeper will indicate that a discharge is pending- this is also useful to test out the circuit prior to launch by counting the beeps and knowing that your charge will fire!
Also up for consideration is a magnetic activation switch- this allows you to arm/acknowledge/safe virtually any electronics system without physical contact. What does this mean? Instead of having a rotary switch to arm your altimeter, you have a decal over an area of the tube on which you apply a magnet (provided, but also available from almost any fridge in a pinch!). The status of the switch may be indicated via LED , which shines through a thinned area of the cardboard tube/poly nose. The stronger the magnet, and the brighter the LED, the less modification you have to do. The unit may ship with a neodymium magnet that will work through 1/4" of non-ferrous material. I say "may" because I have neither inventory nor a business plan to retire on this. What I can say is that it will likely be significantly less expensive than the other magnetic switches on the market. My hope is to gauge interest, and even if there is no interest, I'm happy let folks know that it's possible to improve it. What sets this apart critically is that it is all solid-state, there are no moving parts like you'd find in a reed switch, so G-force in any direction would have no impact on the switch.
Combined, these two improvements can deliver safe dual deploy to motor-eject low and mid-power rockets, or provide redundancy for motor eject/ main deployment of small high power rockets.
