Tracker on the cheap (cheep, cheep!)

Discussion in 'Rocketry Electronics and Software' started by sooner.boomer, Jan 10, 2019.

Help Support The Rocketry Forum by donating:

  1. Jan 10, 2019 #1

    sooner.boomer

    sooner.boomer

    sooner.boomer

    Well-Known Member

    Joined:
    Mar 21, 2011
    Messages:
    2,344
    Likes Received:
    48
    I'm parsimonious. Frugal. Penny-pinching. Oh Hell, I'm cheap. I hate losing rockets (like I said, I'm cheap). So, I'm trying out a bodged-up tracker in hopes of getting something for a little of nothing. It might not work, but then I'm not out a lot of money. What I've ordered are a 433 MHz alarm Window/Door Sensor transmitter https://www.goldmine-elec-products.com/prodinfo.asp?number=G4568 and a 433 MHz Super-Regen 433 MHZ Receiver https://www.goldmine-elec-products.com/prodinfo.asp?number=G22483 . I've got a 400MHz Yagi I built a long time ago using brass rods and a piece of PVC. I plan on attaching the receiver directly to the antenna, and adding on a minimum-parts LM386 amp and speaker (will probably need to fiddle with shielding). The transmitter may need additional circuitry to make it give a continuous "squawk" but that can be done with a 555. The transmitter runs off of a 9 v. battery, so it won't be the smallest tracker. The receiver runs on 5 v. so another 9 v. battery and a small 3-pin regulator should do the job there. I'm thinking I'll wire the power to the receiver through a momentary contact push button switch to conserve power (I'm the worst at leaving stuff turned on...). Not sure exactly how I'll test range w/o actually launching. Maybe a kite? Or I might be able to talk someone into putting the transmitter in their office window in one of the taller buildings on campus.

    I'll get back as soon as I've tested and let you folks know how it turns out.
     
  2. Jan 10, 2019 #2

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Supporter TRF Sponsor

    Joined:
    Feb 3, 2012
    Messages:
    2,898
    Likes Received:
    155
    How are you going to send your ham callsign? I also doubt that it has much range... it was designed to be used for very short distances (probably under 50'), its output is probably under 10 mW.
     
  3. Jan 10, 2019 #3

    billdz

    billdz

    billdz

    Well-Known Member

    Joined:
    Feb 11, 2017
    Messages:
    768
    Likes Received:
    10
  4. Jan 11, 2019 #4

    neil_w

    neil_w

    neil_w

    Balsa enthusiast TRF Supporter

    Joined:
    Jul 14, 2015
    Messages:
    4,645
    Likes Received:
    224
    Location:
    Northern NJ
    Enticingly cheap, but I was under the impression that 2G service is unavailable in many places nowadays?
     
  5. Jan 11, 2019 #5

    billdz

    billdz

    billdz

    Well-Known Member

    Joined:
    Feb 11, 2017
    Messages:
    768
    Likes Received:
    10
    ATT has discontinued 2G service but T-Mobile and its MVNOs still have it. I've been using the $5 a month Speed Talk SIM card with no difficulties. The $17 K8 works but I prefer the MD-601, costs a little more ($31) but I like the app better. See https://www.fasttech.com/product/7219000-md-601-mini-personal-gsm-gprs-gps-tracker-locator

    For larger rockets, as long as your launch site has cell service, you can't beat an old Android phone (under $40 on eBay) placed inside the rocket with the Insane Rockets app and a free FreedomPop SIM card. That gives you GPS tracking, altimeter, and flight data, with no monthly fees. See https://www.insanerocketry.com/help/help.html
     
  6. Jan 11, 2019 #6

    sooner.boomer

    sooner.boomer

    sooner.boomer

    Well-Known Member

    Joined:
    Mar 21, 2011
    Messages:
    2,344
    Likes Received:
    48
    Don't need ham ticket/callsign. This is a very low-power type-accepted transmitter. The main idea behind this is 1) to build something (emphasis build). 2), no, I don't have a working cell phone service, or a cell phone I can stick a SIM card into. If you want to donate one... 3) not counting any new batteries I might have to buy, I'll have less in this project than in a Big Mac Combo Meal. 4) this is an experiment. It might not have sufficient range to be suitable. This is an experiment. I'm helping the odds with a Yagi. I don't know if the receiver is any good. This is an experiment. I also have a hand-held scanner (somewhere...) that can do the 400MHz range. I may turn the thing on and cause the world to collapse into a black hole. This is an experiment. Be prepared.
     
  7. Jan 12, 2019 #7

    DaveW6DPS

    DaveW6DPS

    DaveW6DPS

    Well-Known Member

    Joined:
    May 28, 2013
    Messages:
    81
    Likes Received:
    15
    I do have a ham license and suggest it if you plan to experiment with radio stuff. There are a number of licensed and unlicensed services sharing the 70cM bandwidth, and I don't agree with your assessment that this project would not need specific certification or a ham license.

    I have done a similar build. I got the idea from another site, where the ham built a receiver like you are talking about.

    You might get some useful ideas here:
    https://www.qsl.net/w6dps/70cm_mini_transmitter.html

    https://handyham.blogspot.com/2017/06/simple-70cm-fox-hunt-reciever.html
     
  8. Jan 16, 2019 at 1:12 PM #8

    RKeller

    RKeller

    RKeller

    Well-Known Member

    Joined:
    Jul 31, 2014
    Messages:
    981
    Likes Received:
    4
  9. Jan 16, 2019 at 5:07 PM #9

    cerving

    cerving

    cerving

    Owner, Eggtimer Rocketry TRF Supporter TRF Sponsor

    Joined:
    Feb 3, 2012
    Messages:
    2,898
    Likes Received:
    155
    Unfortunately it's on the 70cm band which not a license-free band in North America. You'd need to have a ham license, and even with one it's not technically legal because it has no provision for transmitting your call sign. If it sent out the call sign in Morse code as the beacon it would be fine... it looks like there's some kind of processor controlling the RF module, so it might be possible to hack the software to make it do that.
     

Share This Page