The Inventor’s Allotment

Excuse the terrible pun in the title there. I’ve found something that Lucy and I will definitely be trying in some form, at some point…It involves creating a flexible mould and then growing a gourd inside it so that it grows into the shape of whatever you’ve modelled.

Portrait Gourds Grown in Molds

I’ve been doing some work on the data-link front. This was my plan to transfer data from sensors on the allotment to our house using radio transmitters and receivers. First off I contacted a company called Radiometrix. They had a nice looking transceiver module with a 10km range (perfect as we’re only 1km from the allotment) which I emailed them about to ask the price. I got a reply saying that the module I’d enquired about wasn’t legal for use in the UK yet due to the frequency it operates on. They then said if I supplied my business’ contact details that they would send me a quote and tell me what other modules might suit my application. I replied with my contact details but saying that I wasn’t a business…I’ve still not heard back from them, oh well.

After being dismissed by Radiometrix because I’m a lowly member of the public and not a Limited Company, I managed to track down alternative radio gear on good old eBay. The seller has a large range of very cheap kit. The ones that really caught my eye were this transmitter and the matching receiver. The transmitter supposedly has a range of 4000m, more than enough to bridge the gap between the allotment and our house. With a bit of luck and a decent antenna setup the receiver should be able to pick up the signal.

To start off with I’ve ordered one transmitter and one receiver to test the modules out. The seller on eBay offers flat rate postage of $4 no matter how many items are ordered, making it pretty cheap to do multiple orders should I need to get more bits. The total for my order including postage and the Paypal currency converting fee came to £11.40, much cheaper than one of the Radiometrix transceivers I imagine.

The modules don’t feature any kind of encoder chips so I was planning to implement software based Manchester Encoding on a PIC 16F88 chip to make the data transfer reliable. When the modules arrive I’ll post the results of any testing.

I’ve not made anything electronic for the allotment yet, but I thought I’d better document some of my ideas to justify the blog title, and so I don’t forget them…so anyway, here goes:

• Solar power for the shed -
  • Some solar panels on the roof will either run small items directly or will charge batteries for use when the weather’s bad. I may run some LED lighting, power the radio or maybe run some PIC based electronic circuits.
• Solar soil heating -
  • Using old cooling pipes from a fridge I’ll make a solar water heater which then circulates the hot water through pipes laid under the soil to make it toasty warm. I might not need to do this one, but the idea appeals to me. This solar heater is similar to what I have in mind.
• Data logging -
  • Using one-wire temperature sensors from Maxim/Dallas IC and possibly light, humidity and water sensors, I’ll create a data-logging system to monitor various environmental statistics.
• Wireless data link -
  • Our house is only 0.5616 miles from the allotment, as the crow flies, so a wireless link of some kind is not out of the question. Depending on what kind of link I can get working I’d probably use it in conjunction with the data logging system to send back information from sensors.
• Wireless voice communications -
  • I bought a cheap pair of ‘walkie-talkie’ type radio transceivers a while ago. They claim to have a 3km range (line-of-sight) and although it’s quite crowded between here and the allotment, it’s less than a kilometer away so I have some hope of it working. I’ll test that at some point soon. It’d be good to be able to hassle Lucy while she’s down there slaving away.
• Greenhouse climate control -
  • To keep the temperature in the greenhouse stable I plan on making a solar powered climate control system. This would consist of a temperature sensor and maybe a humidity sensor linked to a servo motor which will open and close a hinged hatch in the roof. When the temp rises beyond a preset level the hatch will open and when the temperature falls the hatch will close.
• Automated watering system -
  • This will monitor soil moisture and air temperature then water plants based on the readings. It may be solar powered where possible and the water will come from butts that have collected rain. It will water at night to minimise water loss by evaporation.

Those are just some of my ideas at the moment. I’ll update my progress as I go along and write up new ideas whenever I think of something that’s half-decent. I’m not aiming for 100% practical ideas, some things I’d just like to try out to see if they can be done and for the experience of doing them.

I can’t wait until I have some more free weekends, then I should be able to put some of my plans to the test.