Show us your PicoAlt battery mounts!

[lalligood]

I purchased a PicoAlt PICO-P1 (peak only) altimeter several months ago but I haven't used it yet because I haven't come up with an easy to implement method of mounting it in my rockets. At best, I've gotten no further than merely contemplating some ideas about what batteries to use & how to mount them in my rocket. I feel like I've hit a mental block (or has it turned into trepidation?!) about using this tiny alt in a rocket...

Would anyone be willing to share (text or pics are more than welcome) on what batteries they are using & how they have them attached to the unit as well as how it's mounted in their rocket(s), please?

Thanks for the help & for sharing

 

[jsdemar]

Originally posted by lalligood
Would anyone be willing to share (text or pics are more than welcome) on what batteries they are using & how they have them attached to the unit as well as how it's mounted in their rocket(s), please?

I flew a PicoAlt AA1 last week in a BT-50 rocket. The altimeter and battery holder were mounted on a piece of 1/32" ply that slid into the payload section. The length was cut to fit snug against the nosecone and bulkhead. I used a 12V type 23A (N size) battery. To get it to reliably fire an e-match, I put a 1000uf capacitor across the battery.

For the PicoAlt P1, you need 4.5V to 5.5V (it doesn't have a regulator). A 6V Lithium battery will fit in the same battery holder. But, you'll need a diode in series to drop the voltage to below 5.5V. That battery is a little overkill and will last a long time. Otherwise, use a stack of 3 tiny 1.5V coin cells (no diode needed) or two tiny 3V coin cells (use a diode in series). There are all sort of battery holders options out there, but not available at radio shack. The other option is to add a voltage regulator. The 78L05 in a TO-92 package (search Digikey) would work fine with a >=6V battery.

-John

 

[ultrasonicTim]

Here's my contribution. I use a stack of two 1225 3V lithium coin cell batteries. The holder I think I got from Mouser online. I put the center post (-) of the battery holder straight through the board of the PicoAlt and soldered it in place. I clipped the back lead (+) of the battery holder and soldered a wire from the top side of the clip down to the board of the PicoAlt. Because the wire is so short I added a piece of shrink wrap tubing over it because the wire insulation would melt off when I was trying to solder it in place. I use a short piece of plastic drinking straw slipped over the clip to turn the unit off. I've used this altimeter with small Estes LPR type rockets up to high power L2 rockets on I & J motors. Probably the most extreme trip it took was in my PML Explorer running an I218R (over 20G's to 3378ft). It has been pretty successful for the most part but the clip is susceptible to flexing causing the unit to lose power (this has only happened 1 time IIRC in close to a dozen flights). I put this inside a small piece of body tubing with a small "breather" hole drilled in it. One end is capped with a piece of balsa transition glued in place and the other is held in place with an old nose cone or balsa transition with masking tape to secure. I would typically clip this in place on the nose cone or on the shock cord where the parachute mounts.

 

[ultrasonicTim]

Just another perspective.

 

[ultrasonicTim]

And the last one...

The batteries don't last a really long time because they are quite small and the altimeter draws a decent amount of current. Find a good battery supplier online and they are not that expensive (under a buck a piece).

Tim

 

[falingtrea]

You could also use something like this:

Nicad pack

I have always been a little leary of battery holders in a rocket, unless you can align the holder so that acceleraction or decceleration will not cause the battery to disconnect.

 

[jsdemar]

Originally posted by falingtrea
You could also use something like this:

Nicad pack

I have always been a little leary of battery holders in a rocket, unless you can align the holder so that acceleraction or decceleration will not cause the battery to disconnect.

This is a very tiny board... only needs a couple of coin cells, like shown in the previous messages. That NiCd pack is heavier than the rocket I flew the alimeter in! Connectorized packs are a good idea in general though, for bigger rockets. Also, tie-wraps work great to keep 9V batteries in their holders.

Originally posted by ultrasonicTim
Here's my contribution. I use a stack of two 1225 3V lithium coin cell batteries.

Did you use a diode in series with + side to keep the voltage below 5.5V?

John D.

 

[ultrasonicTim]

John,

Yes, I did put in the diode. That's what's under the shrink wrap. Until you mentioned the diode in your post, I had completely forgotten about it.

Tim

 

[konoctipirate]

I did exactly the same thing. Bought the altimeter, had it sit around for a few months while I pondered how to mount and use it interchangeable across multiple rockets.

The following solution fits nicely into a film cannister which then becomes the bay.

So my solution to the conundrum of Pico P1 altimeter mounting was , after much head-scratching, to take a tongue depressor stick , cut out a hole big enough for the altimeter, and to carefully epoxy the altimeter into the hole. I bought a simple battery holder (N1 I think) from Radio Shack and cut out the middle part so I was basically left with two spring holders. I chose about the smallest watch batteries I could find that would get to the right voltage and then positioned the 2 parts of the battery holders so that there was good spring load either side of the 3 batteries. Oh, and I wired a switch inline too. The batteries are secured with tape around the two parts of the battery holder.

Total weight: 0.3 oz
Length: 2 inches
Width: 3/4 inch
Diameter: < 1 inch

You could make the diameter even smaller by lengthening the stick you use and mounting the switch next to the battery holder so the whole thing would go in smaller diameter rockets.

I've just built a rocket with a PML intellicone. I've glued a film cannister lid to the aft end of the ebay in the nose cone. The altimeter pops into the cannister and snaps onto the lid. Bingo.