Bug / Tracking Transmitter

Status
Not open for further replies.

hugoender

New Member
Hello all,

I would like to make a very simple and preferably small transmitter on perfboard/prototype board (I do not have the materials to make PCB's).

Now while most of the circuits I find online are for FM transmitters, I am open to any other methods of tracking that you guys might have. For the FM transmitters, I found this to be the coolest/easiest one since it does not require a pcb: **broken link removed** . However, the LM3909 is discontinued. Can a 555 IC perform the same operation as that LM3909?

Any ideas will be helpful, but remember, I want simple, non-pcb, and somewhat small. Thank you.

Edit: Also, if there is a way to minimize the error in making a hand made inductor out of wire that would be great. By this I mean, I would prefer to have a variable inductor that I can just put a screwdriver to (like a potentiometer) and modify it's value to get the desired frequency
 
Last edited:
The very old LM3909 IC doubles the 1.5V to 3.0V for the transmitter to operate.
A 555 IC has a minimum supply voltage of 4.5V.
Try using a 6V battery and a 555 turning the transmitter on and off.

The transmitter uses a trimmer capacitor for tuning. It is adjusted with a plastic screwdriver.
 
Krumlink said:
the 7555 can run off of 2VDC.

**broken link removed**
Click to expand...
But its minimum output high current is only 2mA when its supply is 5V and its current is much less when its supply is less. The transmitter needs more current.
 

What about using the TLC555? Here is the datasheet: https://www.electro-tech-online.com/custompdfs/2008/06/tlc555.pdf

This IC is from Texas Instruments and can operate at as low as 2VDC. I cannot seem to find how much current it can source/sink at 2VDC from the datasheet. It says it can sink over 100mA and source over 10mA but those are probably not the numbers for a Vdd of 2V. If someone can tell me where on the datasheet this information is found (and what they call it) I would greatly appreciate it.

If the TLC555 still cannot provide the current needed, is there another IC that does what the LM3909 does (double the voltage)? I don't mind operating a 555 on 6V but if I don't have to then I'd prefer not to (to minimize size). Thank you guys for your responses.
 
I looked on the datasheet for the LMC555 that spec's only with a 5V and higher supply.

The datasheet for the TLC555 has spec's for a 2V supply and the output voltage drops to only 1.5V when its load current is only 300uA which is next to nothing.
The transmitter needs much more current.

I think the range of the transmitter depends on its supply voltage.
With a 2V supply its range might be across the street (30m).
With a 6V supply it might be 200m.
with a 5V supply it might be 400m.
 
why does 5 V give more range than 6 V ? I think you got your figure switched

remember hugo that as distance doubles the power will be quartered when its three times the distance the power will be 1/9
 
audioguru said:
The datasheet for the TLC555 has spec's for a 2V supply and the output voltage drops to only 1.5V when its load current is only 300uA which is next to nothing.
The transmitter needs much more current.
Click to expand...

Where did you see 300uA? Could you please let me know what page and what area of the page you are getting this from because I cannot seem to find it. Is it the Idd (supply current) that tells you how much current it outputs? If so... the data sheet says 250uA at 25degrees and 400uA for full range (these are max values).
 
Thunderchild said:
why does 5 V give more range than 6 V ? I think you got your figure switched
Click to expand...

Are you talking to me? I don't know what you mean with this. I would think that the higher the voltage the longer the range.

Thunderchild said:
remember hugo that as distance doubles the power will be quartered when its three times the distance the power will be 1/9
Click to expand...

Yes, the power is inversely proportional to the distance squared. I graduated with a bachelors in electrical engineering so I have the book knowledge, now I just need the practical knowledge (which is only acquired by doing... which is why I am here )
 
There are several tables given on the data sheet. One table list test conditions @Vdd = 2 volts. the other tables 5v etc.
 
Mikebits said:
There are several tables given on the data sheet. One table list test conditions @Vdd = 2 volts. the other tables 5v etc.
Click to expand...

Yeah, I guess my question is which value on that table is the current that is present at the output of the IC (how much current does it source/sink)? Or does it always source 10mA and sink 100mA as long as the voltage source is between 2-15VDC?
 
On the page with the spec's for a 2V supply, it lists the Output Voltage with 300uA sourcing current (output high).

The output current from a Cmos IC depends on its supply voltage.
The output low current with a 15V supply is a minimum of 100ma with a max allowed current of 150mA.
The output high current with a 15V supply is at least 10mA with a max allowed current of 15mA.

The 2V page shows the minimum output high current of 300uA.
Didn't I repeat this on another website?
 
Yes, the power is inversely proportional to the distance squared. I graduated with a bachelors in electrical engineering
Click to expand...

I am really surprised that someone with a EE cannot read a simple spec from a data sheet.
 
Mikebits said:
I am really surprised that someone with a EE cannot read a simple spec from a data sheet.
Click to expand...

Well, like I said before, book knowledge != practical knowledge. I wish my college would have made practical application of the learned material a requirement but unfortunately they didn't and so now I am trying to learn it on my own.

Yes, it is a simple data sheet, and it is easy to read numbers, I would just rather have someone tell me exactly which value on the table corresponds to the current source/sink of the IC instead of just going with what I think is the correct value and not being sure. If you solve a problem and you think the answer you got is correct when indeed it is not, then all you have done is learned the wrong way of solving that problem.

Besides, having a degree has nothing to do with how much you know or how smart you are. It only decides how much you are going to get paid
 
I am interrested in building a tracking device that tells me when someone is in the proximity. around two mile range is what im looking for.
 
i was thinking of using a gameboy colour as the screen for the tracker , but how do i make the tracking device its self? Maybe i could pull apart an old walkietalkie and use its componenets?
 
Last edited:
jessiejames666 said:
I am interrested in building a tracking device that tells me when someone is in the proximity. around two mile range is what im looking for.
Click to expand...
The "someone" must have a transmitter with about a 1/4W output. You must have a sensitive receiver and omni antenna. The indication will change when an obstruction is in between.
 
jessiejames666 said:
i was thinking of using a gameboy colour as the screen for the tracker , but how do i make the tracking device its self? Maybe i could pull apart an old walkietalkie and use its componenets?
Click to expand...
It is extremely complicated to show tracking on a screen. A walkie-talkie is extremely simple.
 
Tracking transmitter

I also am trying to build one of these. does anyone have any schematics on how to do this? Any information is much appreciated. Thanks
 
Status
Not open for further replies.

Similar threads

P
  • Question
Project or Book with 2 Watt VHF transmitter for tracking
Replies
16
Views
2K
preWarp
P
D
  • Question
Bluetooth integrated FM transmitter project
Replies
19
Views
4K
audioguru
S
  • Question
512Hz Mini Transmitter
Replies
17
Views
5K
danadak
M
Someone knows if there are a Bluetooth audio emitter module [Just Emitter/Transmitter] that works with all devices including apple AirPods .
Replies
6
Views
12K
mcbrown
M
B
Calling all Makers, Segway Music Stand Distance Tracking
Replies
2
Views
1K
Pommie
P
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…